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How to: The Borg Warner 4405 Transfer Case Rebuild Diary

Prefix for threads which are instructional.


EF Tranny Guru
Moderator Emeritus
February 8, 2003
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City, State
Sacramento, CA 95827
Year, Model & Trim Level
1992 XLT
I am going to try and put this entire thread together much as I did the 4R70W Diary, so those just needing basic info do not have to sift through a lot of chatter throughout the thread. I will create and link another comment thread for those comments - which is here:

and until at least the first half of this Diary is done, lock this thread. (unlocked for now as the first half is done)

Much of this initial info came from the FORD manual, with some edits. While the initial part might not make a lot of sense to some, once the pictures start coming in I hope to try and explain what this all means in 3d nuts and bolts inside the TC. I always think theory of operation is essential to any component you are working on, and this is no exception. This first stuff is important to understand how this TC works though and I recommend reading and at least trying to comprehend it... even without pictures. I admit it is not easy.


The Borg-Warner Control Trac 44-05 transfer case was used in the Explorer (4WD) vehicles starting in 1996. The transfer case transfers power from the transmission to the rear axle, and also to the front axle when electronically activated.

Mechanical Operation

In the 4X2 mode, torque from the transmission is transferred to the input shaft which, in turn, drives the rear output shaft that drives the rear axle assembly. Though the input shaft and the rear output shaft are independent of one another, there is a mechanical gearing interconnect that locks them together as a unitary assembly during normal operation. That through power from the transmission is transmitted to the back wheels for a 4X2 engagement. Shifting to 4WD is done electronically by energiizing the electromagnet, which in turn actuates a very interesting electromechanical ball ramp clutch assembly. (More on this later)

The electromechanical ball ramp clutch assembly drives the drive sprocket after the generic electronic module (GEM) activates the clutch coil. The drive sprocket turns the chain which rotates the front output shaft and front driveshaft. In other words the input shaft and output shaft are locked, and the eledctromagnet actuates the gearing (through a clutch) that adds the sprocket attached to the chain drive, which then adds the front output shaft to the equation. (Confusing enough?)

The high-low shift is accomplished when the reduction shift fork moves the reduction collar to lock the planetary gear set to the output shaft. Torque from the input shaft is then transmitted through the sun gear, which then turns the front planetary gear set front planet The front planetary gear set front planet which is now engaged provides transfer case speed reduction.

Transfer Case Functions

There are three modes on the transfer case, Auto, 4WD Low, and 4WD High. Neutral is only available as a dealer installed option.

C-Trac Function

This is the interesting part. The C-Trac transfer case transmits torque to the front wheels through an electromechanical shift assembly after a predetermined change in speed between the front and rear driveshafts is detected. These driveshaft speeds are determined by two Hall effect sensors which send a signal to the generic electronic module (GEM). If the GEM detects a change in speed between the front and rear driveshafts, it activates the transfer case clutch coil with a varying current to minimize the change in driveshaft speeds.

Low Range Function

In 4WD Low Range, the transfer case electromechanical clutch locks the front and rear driveshafts for maximum 4WD traction. The transfer case motor also rotates the shift cam to move the reduction fork to the 4WD low range position. This low range shift is accomplished through a planetary gear set which changes torque to the driveshaft from 1:1 to 2.48:1 ratio.

This is the transfer case being rebuilt in this thread.


The all-wheel drive (AWD) transfer case is a two-piece aluminum, chain driven, viscous clutch type unit. This produces a system in which all-wheel drive is always activated. All-wheel drive transfer case is automatic and has no external controls.

The viscous clutch is a non-repairable, torque distribution device. The internal construction of the viscous clutch consists of alternating plates that are connected to the front and rear outputs of the transfer case. The viscous clutch is filled with a high viscosity fluid which flows through slots in the plates. The resistance to shear causes the plates to transmit torque at the needed ratio. The ratio that torque is transmitted at is approximately 35% front and 65% rear.

A front differential compensates for the difference between the inner and outer wheels. However, when one driveline component travels farther than another, there will be driveline or torsional windup that must be released.


Torque is transmitted through the input shaft to the planet carrier assembly. Torque flow continues through the gear ring to the rear output shaft. Torque also flows from the planet carrier assembly to the sun gear shaft, which is splined to the drive sprocket. The drive gear is connected to the driven sprocket by the drive chain. Torque continues through the driven sprocket to the front output shaft flange. The viscous clutch provides the connection between the gear ring and the sun gear shaft.

The AWD is not being rebuilt in this diary.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Initial note: Some changes occurred in 98 when the Vehicle Speed Sensor was moved from the transfer case to the rear differential. For that reason a 1998 4405 will not provide a necessary VSS input to a 97 or 96.\ model year vehicle.

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The following is a much more detailed description of how the Control Trac 4405 operates:

Automatic 4 Wheel Drive (Control Trac) Features and Operation

The A4WD system is an electronic shift 4x4 system that allows the operator to choose between three different 4x4 modes. The operator can switch between A4WD and 4WD HIGH modes at any speed. To engage or disengage LOW range, the vehicle speed must be less than 5 kph, the brake depressed, and the transmission must be in NEUTRAL.

A4WD (C-Trac)

In A4WD, the generic electronic module (GEM) varies the torque split between front and rear drivelines by controlling the transfer case clutch. Under most conditions, the GEM activates the transfer case clutch at a minimum duty cycle (percentage of time the clutch is turned on) which allows for a slight speed difference between the front and rear driveshafts which normally occurs when negotiating a corner on dry pavement. When the rear wheels are overpowered, the GEM detects this slip condition, and the duty cycle to the transfer case clutch is increased until the speed difference between driveshafts is reduced. In this manner, the GEM can redirect 4 to 98% of engine torque to the front wheels when the rear wheels lose traction, yet still allow operation in the A4WD mode on dry pavement.

Feature inputs:

l 4WD mode switch.

l Transmission range (TR) or digital transmission range (DTR) sensor.

l Vehicle speed sensor (VSS) switch.

l Front/rear driveshaft speed sensors.

l Contact plate position inputs A, B, C, D.

Feature outputs:

l Solid state clutch relay (pulse width modulated signal: grounded when relay is on, battery potential when relay is off).

l A4WD indicator (ground when activated, open circuit when deactivated).

Shifting Between A4WD and 4x4 HIGH

Shifts between A4WD and 4x4 HIGH can be made at any speed. Listed below are the inputs and outputs needed by the GEM to execute a change between any of these modes.

Feature inputs:

l 4WD mode switch.

l Contact plate position inputs A, B, C, D.

Feature Outputs:

l 4x4 shift motor relay outputs.

l Solid state clutch relay (pulse width modulated signal; grounded when relay is on, battery potential when relay is off).

l Cluster indicators (ground when activated, open circuit when deactivated).

Shifting Into/Out of LOW Range

When shifting into or out of LOW range, the GEM requires that the vehicle speed is less than 5 kph, the brake is applied, and the transmission is in NEUTRAL.

Feature inputs:

l 4WD mode switch.

l Contact plate position inputs A, B, C, D.

l VSS sensor.

l Brake input (battery voltage when brake is depressed, open circuit when not activated).

l Transmission range (TR) sensor (ground when transmission is in neutral, open circuit otherwise).

l Start/clutch depressed input.

Feature outputs:

l 4x4 shift motor relay outputs.

l Cluster indicators (ground when activated, open circuit when deactivated).

4WD Mode Switch

The 4WD mode switch is a rotary switch which allows the vehicle operator to choose between A4WD, 4 HI, and LOW range positions.


The generic electronic module or GEM controls the operation of the 4x4 system.

Vehicle Speed Sensor

The vehicle speed sensor (VSS), mounted on the rear of the transfer case, informs the GEM of vehicle speed.

Front/Rear Driveshaft Speed Sensors

The Hall effect sensors are mounted to the transfer case which is used to detect the speed of the front and rear driveshafts. This input is used by the GEM primarily to control A4WD operation.

Transfer Case Shift Motor Sense Plates

The shift motor sense plate, an integral part of the electric shift motor, informs the GEM to the position of the transfer case.

DTR Sensor, TR Sensor

This sensor, located on the left side of the transmission, informs the GEM when the transmission is in the neutral position.

Electric Shift Motor

The electric shift motor is mounted externally at the rear of the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the A4WD, 4HIGH, and LOW range positions.

4x4 Shift Motor Relay

The 4x4 shift motor uses a module containing two relays which, under the control of the GEM, shifts the transfer case shift motor between A4WD, 4HIGH, and 4LOW modes.

Solid State Clutch Relay

The solid state clutch relay is used to activate the A4WD clutch within the transfer case.


4405 Disasembly

The disassembly portion of this thread starts here. :D

I thought I would start with a couple of views of a 4405. This isn't the one I am rebuilding, and is missing the shift motor, but otherwise 4405's generically look like this:


This is the front side. The splined shaft is the input, and the round connector hooks up to the driveline to the front wheels. They turn together only if the clutch is engaged inside the transfer case.

Here is another view, showing the backside:


The output shaft can be seen in this picture (and again there is an absence of a shift motor). The output shaft is separate from the input shaft. They are connected only when the shift motor moves the "hi-low collar" (As FORD calls it. I'd rather call it the "sliding shift gear".)

Now before you work on one of these let me make a suggestion...CLEAN IT!
Engine degreaser works just dandy.


Try not to get it into the vent hole. Otherwise anything on it is fair game. (for the record before I power washed it I DID plug that vent hole. )

I coated it using a foaming degreaser and let it sit for about 30 mins...


After I plugged up the vent hole I used a pressure washer and it was all nice and clean to work on. A word of advice here. If you like to get your Explorer in deep water, run a line from this vent up into the engine compartment where it will always be above water.

One last thing before we take it apart.... drain all the old fluid out... there are two plugs, a fill and drain, I don't care which one you remove... the drain one really is only the "drain" once it is installed. Either is fine. Here is the drain plug:


With the case out, things can be difficult to remove because the case moves as you try to unscrew them. An air powered tool can make this a snap - the hole on the plug is the same size as a 3/8's socket.

So, case drained, cleaned, blown dry and ready to go - time to get to work! :salute:

Reminder: If you have questions, comments or want to throw rocks at me, do it "here":

I found that a couple of 2x4's sitting on top of one another at the one side of the case and a 3/4 inch piece of wood to protect the input shaft (and my work table) at the opposite end made the case sit more or less level on my bench with the rear case side up. First up was to remove the nut from the output shaft. I had PB Blaster'ed it the night before. I was concerned that I did not have anything handy to keep the shaft from turning as I tried to undo it. If I had it in a vehicle, I think I'd bust this loose before I took it out (hint).

Anyway I put the air gun to it, and it spun loose easily


(for those with good powers of observation you will notice the gun is the Harbor freight "Earthquake". It is a great little gun for the money and can put out some torque.)

Anyway it broke free first try and I backed it up to the point of off. The green stuff is either some type of thread locker or something built into the nut to accomplish the same thing. makes me wonder if it is a reuseable nut w/o thread locker.


This is the point that FORD suggests you take a marker and make some orientation marks on the input shaft and this flange so they go back together in the same position. This is suggestive of the notion that they are balanced at some point in the manufacturing process - something I have a hard time believing. I also don't think it is all that critical, but, for the record, FORD wants you to. (I didn't).

The flange didn't yield to my efforts to just use my hands to pull it off. I thought to myself - "I bet that sucker is really on there"... so I got out a puller..


I didn't need it. If I had used a hammer to tap around the edges I am sure I would have gotten it loose. It wasn't on the shaft all that tightly...


Look into the bore.... see that yellowish thing?


That is the gear for the vehicle speed sensor. That means this is a 97 or earlier because in 98 they eliminated that in the TC and put it on the rear differential. (I have done my homework!)

Splitting the Case

The case halves are held together by 17 or so self tapping screws (so when you remove them if you see little slivers of metal, relax, it is normal.) They use Torx bits... like there


I found that the impact gun was a nice tool to break them all loose, then I could use the smaller butterfly gun to spin then all out..


finally I used my fingers to remove them from the case...


With all the screws off, it is time to split the case. before we do, let me remind you - this is magnesium. Great stuff... light, strong (it will also burn! - gawd forbid - a magnesium fire is something you will never forget) but it is fragile. Take care with the case. The case has several "bosses" or ears on it, to assist you in splitting it. I ws going to use a hydraulic spreader and then I thought better of the idea, because...a) this is a magnesium case, and b) who else has one of those around....

I wanted this to be a diary anyone could use, more or less.... so I inspected tha case and found a place where my handy old hunting knife might be judiciously driven in between the case halves as a wedge... light force does it, and VOILA, the case started to open up.

This pic shows the bosses, and also the knife. The screwdriver was NOT DRIVEN IN BETWEEN, but used ONLY to gently go around the case and pry up.



On the subject of up... it is important that you bring the rear half of the case STRAIGHT UP on disassembly.... there is a small locator rod in the helical cam assembly you can break if you do not.

Here is the case, SPLIT ! :eek:


Looking at this picture, you can obviously see the chain drive that will cause the front wheels to become driven, making 4x4....on the left the top stuff is all about the electromagnet that operated the clutch, which is that "finned" looking thing underneath. When the electromagnet commands it, the clutch locks up and provides 4WD, or in the case of this tranfer case, it can partially lock up to supply as much or as little front wheel engagement to break free if the rear wheels are slipping (see the intro to this diary if that is confusing to you).

The two shafts sticking up are the slider shaft for the shift fork (this TC's MAIN problem child) and the engagement rod for the helical ramp that moves the shift fork.

Of course in the background is the rear case half we just removed.
Only a few things remain in the case rear half once split. A "blind hole" ball bearing for the front output shaft rear half to ride in, the electromagnet (can you say brown wire?) and the speedo gear and a spacer and oil seal and a couple nifty Hall effect sensors. (oh yes, and the shift motor on the back as well) Sounds like a lot but it really isn't. Set it aside for now. We're gonna delve into the GUTS !!! (calling Dr. Casey! - "I said Bud Light not".... well you know the rest_)

We will start by removing the clutch stuff so we can take out the driven gears and the chain. The top most piece is part of the electromagnet actuator... this is one of the most fascinating parts of this entire transfer case. I will come back later and post some more on this, but the electromagnet does its magic through a ball and ramp gizmo that is ingenious (I think it was first developed by NASA but I might be wrong - still if not, I am happy thinking it was NASA - so don't pop my ballooon). Let's remove this top piece


Turn it over and see what is under it. look at the top underneath and you will see 3 shaped ramps.... identical to the thing under it... and 3 steel balls...


When the electromagnet energizes, these balls travel up the ramps and press the clutch together. Cool or what? Here is a view of the balls and ramps


This is also a piece that is prone to break...if it does, NO 4X4.

We continue.. the top plate of the clutch pack..


And then what I will call, for lack of a better term, an accordian spring



interesting, eh ?

Then a snap ring... more like a circlip actually...


With that out, the entire clutch will come up the shaft and out...


With that out, this side is clear....


But the other side still has one piece... what FORD calls a tone ring.... used for the hall effect sensor to measure shaft speed... we will remove it.... there is a right and wrong way to install this so pay attention to how this comes out!


notice which side goes IN towards the gear!


Now carefully take both gears with the chain attached and pull it straight up and out of the case. Set it aside. (no pics to accompany this as it took 2 hands)

We're deep into the guts now.

Reminder: If you have questions, comments or want to throw rocks at me, do it "here":

With the chain out we continue.... on the one side sits the pump (with the chain out you can now more clearly see the shift fork and the helical ramp mechanism as well)


The other side is just the output shaft to the front shaft


I did not photograph it, but remove the snap ring you see and it easily slides out the other side....

So let's remove the pump. Before I do I want to note that this pump is not a serviceable item. If you had an internal fragging, replace it. Cost ? $40. BUT the filter.... well I am getting ahead of myself... first I present, the pump!


With that out, I can now remove the main output shaft. Ladies and gentlemen, the output shaft! (heaviest thing in the transfer case I think)


This next picture is one of the most important in this entire thread. With a red arrow I have shown where the shift fork rides in the helical cam. Now remember this is only half of the case, and the shaft may have moveed a little due to the ovalling of the bores in the case... but there is not a lot of engagement of the roller on the fork that engages this cam.

The blue is where the fork attaches to the hi-low collar (the thing that shifts between high and low range) and in our case here as you will see, our culprit...


In our transfer case, the Fork has lost all of one nylon guide pad (blue arrow) and MOST of the other side too (red arrow)




Causing one to wonder WHY ? Let's inspect the hi low shift collar


Another, closeup


That fracture tore away at the nylon inserts... there are little shreds of white nylon all through this transfer case !

So for us, we now know what went wrong in this case (I have the advantage of knowing nothing else was wrong)

The back end of our high low collar has some gearing that is used to mesh into the input shaft "business end" to produce HIGH and LOW range. Let's look at ours..... (note: there are machined in little "ramps" in this part, which makes it difficult to tell damage from design and manufacturing)


I'll need to wait new to compare, but looks like maybe someone was impatient and did not stop prior to trying to engage LO range? NOW DO YOU SEE WHY THEY SAY DO IT IN NEUTRAL AND AT A STOP????

Anyway a quick look down into what's left after we removed the high low collar....


I'll come back to this shortly....meanwhile...

The Helical Cam, or Ramp

The helical cam or ramp assembly is seemingly pretty stout. Check yours carefully though for fractures and if you fragged the TC, you may want to replace it... cost ? about $40 (lots of $40 items in this TC). Here is is... this is rotated by the shift motor to produce low range and 4WD


That little pin on the end is why you want to remove the front case at the time of the split straight up.. it is brittle, fragile and easily broken if bent. These CAN get chewed up in extreme cases in the ramp area. And also, DO NOT DISASSEMBLE THIS PART ! It comes out, maybe gets cleaned, and goes back in. Period.

Reminder: If you have questions, comments or want to throw rocks at me, do it "here":


Ok with all this out.... the rear case half only has left in it the planetary and a bearing for the front output shaft.... let's remove that first...

First an oil seal....




Exposing a ball bearing.... let's go remove that. I have a 12 ton press, and the Rotunda tool set for the BW 1354 has a nifty piece that will get a lot of use in this tranny.... so to the press, using this tool....


Popped right out.. now mind you I had the interior case WELL supported during this operation! THIS IS A MAGNESIUM CASE... BE CAREFUL !

The tool and bearing...


Now the planetary..... and my sad tale of woe. I screwed up here and damaged the case.... not that it matters much since I will be using a newly machined replacement, but still.. I hate it when I do something DUMB. I did something dumb here.... let me serve as a warning to others.
The rear planetary will not willingly leave the case. Something is holding it in. A snap ring... Sooo I see a snap ring, and remove it...


It was late and I was tired (warning number one, do not work when you are tired and it is late). The planetary has a bearing, and it still seemed stuck, so I took it to my press.... well it popped free all right, but along with part of the case as well... you see, the snap ring I was supposed to release was UNDER the planetary, not on top. I removed a snap ring designed to hold the ring gear in the case!!! Had I *THOUGHT* before I acted, it would not have happened.

Here is the planetary and the snap ring I missed.



But the planetary sits upside down and it is dark underneath... here is what you are looking for....


Well, anyway by brute force it is out.... so let's take it apart.... to start with let's remove the bearing.... while it will not come off by hand, it is not hard to get off... I used a couple of pry screwdrivers to remove it ... you only see one because I had to use one hand to take the picture...


Here is the bearing coming off...


underneath it is a spacer/collar


Notice the side that goes up! The other side shows where the i interior gear carrier rides against it...


So here they are apart, the planetary (heavy sucker) and the input shaft/sun gear....


Next up.. we will examine the sun gear teeth to see if this should be replaced or not....

Input Shaft end gearing


The input shaft terminates inside the transfer case as a sun gear arrangement and engages the high low collar for locked 4X4 engagement. These teeth are machined at an angle, and designed to engage on the fly.... hence the ramped design to help them mesh I assume... let us look at this input shaft (new is $110) and see if these are ok... I solicit input and thoughts... better yet someone buy me a new input shaft to compare ?

Ok, no takers.... let's look... I'll post a series of pictures





I am thinking this is ok..... seeking knowledgeable input on this one....

The astute observer may have noticed in the prior thread there was a bushing missing in the end of the input shaft housing. NO ? well...Ok, there was.

I have what call a "fingernail test" for bushings. Your fingernails are highly ennervated. (lotsa nerve endings in other words) and if you push your fingernail across a surface, the fingernail nail will signal any irregularities in the surface rather easily. I fingernailed this bushing and WOW, it was bad, so I pulled it....

Here is that pictures.... (the tool was about $20 from harbor Freight)


And the bushing came right out, rather easily I might add... here it is out...


Compared to new, it is ucky. (The 1354 uses the same bushing so I have one to compare...)


The one of the right has the scoring. Could it be re-used? Probably but why if I have a new one?

Once I know whether or not I am re-using this input shaft I will press a new bushing in pace.. using, yep.. that Rotunda 1354 tool! (and my press).

(ps. I have 2 Rotunda BW 1354 tool sets to sell...... PM me if you want one.)

[Edit] Ok I have decided to reuse this one. Here we go. So I mount the new bushing on the tool, like so..


Then mount it under the press....


and press it home... like so


end result?


Now, the old one ws seated deeper.. so before i use this I will check for proper depth... I can use a different drive to press it in further if need be, but the tool was designed to seat it a certain distance inside.

So we have one part "refurbished" for re-use.

Reminder: If you have questions, comments, input or just want to throw rocks at me, do it "here":

Well the major guts are all out. Time to clean up the remaining case half. (the front we already removed the bearing and I mangled the removal of the planetary - so that half is *done*, so to speak.) The rear half has a few things we need to remove... starting with the electromagnet.

This has the only torrington bearing in the entire transfer case....


Under it we see a snap ring holding the bearing on the bore...


It is easier to remove if we move it into this position


And with the snap ring out and some gentle pushing from behind we can remove the bearing...

As we turn the case over to push though.... we have a few things to attend to on the other side.... an oil seal needs to come out...




Under this is the vehicle speed sensor gear and a tone ring....first the vehicle speed sensor gear...



and then a tone ring for the hall effect sensor to measure shaft speed (you can see the sensor sitting close to the ring in this picture if you look closely..


we remove the tone ring...


and what is left is the bearing.


This was not a tight fit... the end of a hammer handle worked well to work it out and loose so I could turn the case back over and remove it by hand..


looking into the bore past the electromagnet we can see the hall effect sensor...


So we turn the case over and remove a single bolt....


and the sensor pulls out...


Oh, you have heard of the "brown wire"? This is the wire that engages the electromagnet.... here it is...we will remove it from the wiring bundle since we need it disengaged to remove the electromagnet...


It fits into the connector, so we need to remove it... this sounds harder than it is... first we remove a locking device... I used forceps, needle nose pliers would be fine...


With that out, I used a small needle punch to push the little, I mean LITTLE, holder finger back and slid the brown wire out...


Here is the entire brown wire...


Notice the bolt on the case with the washer under it. That washer is aluminum. There are three of those holding in the electromagnet.... remove them and as you finish support the electromagnet...


once they are out remove the electromagnet, carefully feeding the brown wire through the case..


Here is where the brown wire ends up...


The rear case half still has a hall effect sensor and the shift motor... let's remove those and the disassembly is DONE.

First the shift motor... three bolts...


There may be some silicone holding it, I had to knock mine a few times with a light hammer to remove it.

Next under the shift motor is another hall effect sensor... a single bolt...


and out..


Oh I also took the time to remove the plugs for filling and draining fluid...


The rear case half is now empty!


(okay, there is a bearing there. Once my blind hole puller arrives maybe I'll give it a go.... otherwise the person who gets the case as a core can remove it.... I am replacing it with new anyway)

[Late Edit: My blind puller set arrived.... so look what happened when I used it:


Someone PM'd me asking what a blind hole puller set was. Let's look. It consists of different sizes of "collets". These expand when a screw is turned into them, and hold items. Here is the business end in the bearing I just removed:


Obviously this is the hidden side we can now see. It inserted unexpanded, like this...and a few twists and it was firmly installed in the bearing bore ready to pull


The slide hammer on this one is smallish... I need to see how to modify it to use a heavier slide hammer - up from the 2-1/2 lbs. Here is the assembled item with the slide hammer

and one last one


When you need one of these, nothing else will work. So now we have removed ALL the bearings.


Reminder: If you have questions, comments or want to throw rocks at me, do it "here":

Comparing New To Old

Well my new Hi Low collar, or range shifter, or whatever you want to call it, arrived today. Interesting comparison to the old broken one.

[Edit: I found a huge disparity is prices for TC parts. I found the best prices overall on this site:]

Now the fracture that disqualified the old one not withstanding.... the difference in the gearing was instructive...

Here is the old and new one side by side (old on left)... [pointing out fracture on the old one in red and the wear on the gears in blue for those of you sight impaired folks.]


And here is the gearing on the new one.... backside/down/into/side, if you will:


And here are two pics of the old one's gearing teeth... this ain't broken here, just WORN...



Now remember, my young friend inherited this TC.... so do not blame him for this wear.... (and he owes me big time for this defense).

So, we have significantly improved the situation insofar as this shift collar is concerned, beyond the fracture.

Next up? the FORK assembly and pads....

OK, I'll be posting the rebuild shortly. I will be using the machined case halves from Omega machine and Tool here in Sacramento, and their modified shift fork. You can read about them here:

Borg Warner 4405 Rebuild Diary - Assembly

Sorry for the delay....I finished the rebuild and uploaded the pics a while back... just needed some time... and just found it.

Ok.... last we left it, I was recommending the OMEGA Machine reman's case halves. I picked them up. Here is what they do:

The rod that the shift fork slides up and down on tends to oval out the bores on each end. So they clean up the bore holes and sleeve them in Bronze for a solid and realigned rod:

Here is one case half:


And the other:


The pump apparently has a tendency to move in the case, and they attempt to remedy this (a minor fix in my mind's eye):


Lastly, the bearing on the output shaft tends to put a lot of sideways ovalling pressure on its bore and they fix this as well with a bore ansd sleeve replacement:


The last Omega fix is a longer engagement "stub" on the shift fork. Old versus new:


Look at the engagement of the old... see how much extra room was left over?


The new fills that in with a roller:

All in all the Omega fixes are reliability boosters and in my opinion well engineered and worth the money (about $350 including tax).

Reassembly - Guts

Ok... you have seen the changes available is the case halves. use your own judgment and balance the cost. This Transfer case is being built using the Omega case halves and the shift fork upgrade. (If you only want to upgrade the Fork it is about $60.)

Reassembly is more or less just a reverse of the disassembly half of this thread.

The shift fork gets new pads:




and of course we will be using the new "shift collar" or whatever whomever wants to call it.

To start I replaed all the bearings in the case halves - easy enough.

Now we will start with assembling the planetary..


we add the shaft assembly


and a spacer... twp pics to show the proper way to put it on...



Next the bearing:


This assembly goes back into the case. the shift collar and fork and pump all mount on top. You need to hold the snap ring open when you install it. I found a gasket scraper (which looks like a one inch head on a regular screwdriver) worked dandy. ANyway here it is back in with the other mentioend items in place on top of it:


Notice the shift fork shaft and the shift motor shaft.


On top of this we drop the clutch and gears for the chain:


The clutch needs to be carefully checked to make sure the bearing in the back is in the proper place. The clutch should look like this:


the other gear looks thus:


the pump pickup anchors in the case side....and a magnet goes in on top:


in the end the magnet secures the pickup:


the pump tab rests in the case cutout for it:


I did not photograph it, but now you add a thin bead of black silicone sealant on the mating flange and add the case top half..... slowly tighten it.... and then go around and tighten to spec.

Guts are IN!

Now it is time for seals and flanges. The outer case bores have metal clad seals that need to be added. Again I did not photo this but it is pretty rote and self explanatory. (My apologies - I will add more pix next time).

Now we add the output flange.... this one is interesting.... the flange mounts of the shaft..and a rubber bushing goes in (see it centered here in the above pic?)

Next we add a washer:


then a nut, that gets tightened to 250 ft lbs! Best finished in the vehicle.


The shaft for the shift motor gets a seal added:


I am sure there is some special tool for this, but you can drive it down with most anything if you are careful. I used a pin punch...all around the edges gently and evenly...


An o-ring seal goes on the "snout" of the motor.... you need to add a bead of silicone seal to the mount... I used blue because it is what I had....


I engaged the shift motor and bolted it in to place.

All that was left was the speed sensor....which on this model was on the TC (later models moved it to the differential case)


That's it.

I apologize for the lackof usual pics.... I was under a lot of pressure this summer and taking pics extends the time for work by 3 or 4x. I'll come back later and add morebut this should give you a good idea of what the reassembly is all about!

job well done glacier 991!

please let me you were you are purchasing your parts from because every were I 've looked they seem to be alot more than you say in the thread
again thanks for taking the time to post the information on the 4405 tc

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I bought my parts from in Spokane Washington.