How to: 4R70W Transmission Rebuild Diary

[Glacier991]

Foreward to this Diary:

I have only been building transmissions now for about 4 years or so. I do not claim to be a pro, expert or genius about this topic. Yet, I have been wrenching for 30 years now and at one time did work for FORD. (Seems like another life). I have built engines, component parts, done A/C, Ignitions, suspensions, etc ...and even have a piece of my metalworking handiwork sitting on another planet. (Another fun story).

I started into auto trannies because of a sense of curiosity.... and what I found on the internet insofar as help for those needing it was concerned made me slightly angry. Those who build transmissions seem to LOVE to impose an air of mystery and mystique about them and try to make folks think only "the chosen few" can actually rebuild them. BULLSH*T. I have even seen folks "pretending" to be helpful pull back their help when it was most sorely needed under the guile of, "Oh well, a valiant try, poor dumb amateur, but now you need to come to ME!"

I know a lot about how automatic transmissions work and how to build them. Yet, I possess no "trade secrets" or "proprietary information" as some foolishly claim to possess. If I discover/learn something along the way.. I will share it - and I am constantly learning. My goal is to see those of you who try ...succeed, not fail and serve as a warning to others (as I see elsewhere.) To assist you, I not only share my knowledge freely, I also loan tools when those are needed. I will steer you to the best buys for parts and help you avoid the scams...I believe that for the ones who have some good automotive skills and want to try - You CAN do it.

Sure, rebuilding an auto transmission is not for someone who can barely change their oil... and in fact probably not for 90% of shade tree mechanics....but I see folks capable of awesome things afraid of auto trannies when they could easily do them. I even see people on other sites who are in the business of AT rebuilding, either as a main profession or a sideline trying to scare folks off from trying to build their own.... feathering their own nests - the same folks who claim to have "trade secrets". GIVE ME A BREAK fer chrissakes. For example - clutch clearance is not a "secret" - "ohh I use .037, instead of .028 to .045." Kill me if you have to tell me.

Also...the amount of material to remove from a clutch piston so you can add extra plates to that clutch and still make it all work, is MATH, not "proprietary information". GET a CLUE guys!

So, I decided to do the Diary series. So far dozens have successfully rebuilt their own automatic transmissions using the Diaries and other reference works, but were inspired here. If you are an advanced amateur, and can pay attention to detail (AT's are all about detail), you can do it.... no matter what "THEY" say. I am here to help. I am not in the automotive trades, nor do you need to be.

I hope my Diary can give you a bird's eye view of the process, and even if you do not decide to "do it yourself", you will have a much better sense of what an automatic transmission is all about. Enjoy.

Glacier



BACK TO WHERE THIS THREAD STARTED:
("Once Upon a Time Long Ago.....")


Alright, there IS a slight tease built in here in that I am a few weeks away from really getting into this. I have slowly been acquiring parts - new pump, new mechanical diode, shells and drums, steels and rebuild kits, brand new valve body, kevlar bands, spiral retainers, new torringtons, new updated accumulator pistons, etc.... so once I get going it will happen pretty fast...

I am starting this thread now for a couple reasons. First, If anyone has ideas they want to throw in, or things they want to know about or see in this rebuild, now is the time to speak up. Secondly, and sadly, I have no use for this trannie once it is built, so if someone wants to have a "build to suit" hi-perf 4R70W this can be your trannie, and I can build it to your specs....

Either way I will try and duplicate or add to what I did with the 4.0 Liter A4LD trannie, only this time with a much more hi perf trannie capable of some significant mods (oh and for the 5.0 V-8 engine). Stay tuned.

ps. those of you that have experience with mod's to this trannie please share with me.

pps. Oh, and...I did previous Diaries sometimes in what was more or less stream of consciousness. Years later when i need to refer someone to something specific, it is a pain. This Diary I am setting up differently. There may in the end be 20 or so separate threads making it up, but it WILL be easier in the future to go to your own particular area of interest. So, on that note...this may be a good place to post and update links to the other threads in this Diary. I'll try and post links at the end of each thread to the next, but maybe ONE place for the whole set would be a good idea... so here goes (this thread will be updated constantly until I have them all in when I finish)

Part 2 -Output Shaft, Ring Gear and Hub (and a discussion of extension housings as well)
http://www.explorerforum.com/forums/showthread.php?t=157283

Part 3 - Torrington bearings and Thrust Washers (including selectives)
http://www.explorerforum.com/forums/showthread.php?t=157376

Part 4 - Servos and Accumulators
http://www.explorerforum.com/forums/showthread.php?t=157428

Part 5 - Direct Drum and Hub
http://www.explorerforum.com/forums/showthread.php?t=157440

Part 6 - Bands (2 of em)
http://www.explorerforum.com/forums/showthread.php?t=157481

Part 7 - Main Planetary and Sun gear
http://www.explorerforum.com/forums/showthread.php?t=157487

Part 8 - Case Support
http://www.explorerforum.com/forums/showthread.php?t=158559

Part 9 - Reverse Shell and Sun Gear
http://www.explorerforum.com/forums/showthread.php?t=158566

Part 10 - Forward Clutch
http://www.explorerforum.com/forums/showthread.php?t=158888

Part 11 - Reverse clutch
http://www.explorerforum.com/forums/showthread.php?t=159597

Part 12 - Transmission assembly up to the Intermediate clutch
http://www.explorerforum.com/forums/showthread.php?t=160569

Part 13 - Intermediate Clutch
http://www.explorerforum.com/forums/showthread.php?t=159423

Part 14 - End Case (pump) Clearance - Selecting the Right Selective
http://www.explorerforum.com/forums/showthread.php?t=160708

Part 15 - Pump Modification & installation
http://www.explorerforum.com/forums/showthread.php?p=1462794#post1462794

Part 16 - Output Shaft Speed Sensor installation
http://www.explorerforum.com/forums/showthread.php?t=161096

Part 17 - Parking Pawl Installation (coming soon)

Part 18- EPC solenoid installation (coming soon)

Part 19 - Shift lever and seal installation (coming soon)

Part 20 Digital transmission range sensor installation (coming soon)

Part 21 - Valve Body - Part 1 - upgrades (In progress)
http://www.explorerforum.com/forums/showthread.php?t=186732

Part 22 - Valve Body- Part 2 - Separator plate and installation (coming soon)

Part 23 - Pan install and button up of transmission. End of Project (in my dreams)

Part 24 - Parts listing with part numbers, cost, and where to buy (coming soon)

Part XX - A Discussion about Friction Material (not sure where it will finally go so for now it is the only double X rated thread on the site!)
http://www.explorerforum.com/forums/showthread.php?t=158669

General Q & A on this Diary: http://www.explorerforum.com/forums//showthread.php?t=161450

Changes to the 4R70W in 2004: http://www.explorerforum.com/forums/showthread.php?t=188119

 

[V8BoatBuilder]

Subscribing for updates.

 

[CDW6212R]

I think that the magic in building an AOD, through the 4R70W, is to get the latest model core to start with. Ford constantly improves lubrication, valve body calibrations, and the solenoids.

In AOD's, the reverse band usually will last the lifetime of the transmission, including all rebuilds. The factory part is cast iron as I recall. A kevlar piece might gain some lifespan for the drum though. There are different pins that can be installed to tighten up the bands.

If you can get Kolene steels and blue frictions at a reasonable price, try them.

I don't know if there is something better, but the last I heard, the MarkVIII direct drum had the most clutches. Various companies sell thinner direct clutches.
There is debate about whether eight or nine thin clutches is actually more reliable than six or seven normal thickness clutches.

Do remember for performance use, to get the three OD "A" servo parts from a Supercoupe. There is also an aftermarket(even larger) OD piston, etc.
Regards,
DonW

 

[Glacier991]

Don, thanks. I was going to see about Alto clutch pack upgrades and kolene steels. Is there a way from the casting number to decipher the place (read vehicle) the valve body was ideally manufactuiurered for ? I plan to mod the VB, but would be curious. Did this transmission (in all of it's variations) go through the stamped steel to cast iron thing with the forward drum or OD? Appreciate your info!

 

[boominXplorer]

as far as i have gone into the 4r70 is though the valve body to install my baumann. Now I am having tranny toubles again. Is this one going to be 2wd?

 

[Glacier991]

well the core is a 96 2WD. I'll need to see what I'd need to do to make it 4WD or even if all that is possible. I know the A4LD like the back of my hand..the 4R70W I am still reqading up on, so any advice, thoughts or info may help me jumpstart it. If the 2WD/4WD/AWD aspect is outputshaft/tailhousing related (as I assume), I'd let a potential buyer decide what he/she wants.

 

[tmsoko]

Check out the first article in the list at this link, the Ford OD Transmissions 101

http://www.tccoa.com/articles/tranny/index.html#

Written by Jerry Wroblewski and very detailed. Should be about all the jump start you need.

 

[Glacier991]

thanks, a terrific link. Here is another. With those 2 and some common sense this should be a fun project. There will be some decisions to make along the way, and I'll tell you I am not necessarily of the school that more plates and thinner steels are the best thing since sliced bread and don't come at a big price in heat production/lack of dissipation.... anyway here is the other link I mentioned:

http://www.mn12performance.com/mn12-techinfo/trans-tech/4r70w_rebuild.html

I'm hoping to take these great links and tie a photo piece into them for a step by step.

(btw... those links together are pretty incredible: ain't the net a great place?)

 

[CDW6212R]

I'll read those myself soon. Thanks Todd for any information, I want to learn anything that I can.

If you haven't yet discovered this, I believe ideally you'd like to use the valvebody that comes with a transmission, so the calibration matches everyting for that model and year.

2WD/4WD is just a matter of changing the output shaft, and tailhousing.

I'll be building a 97 AWD model soon myself. LOL

 

[Glacier991]

Good Don, maybe we can collaborate.

 

[Glacier991]

Ok, I'm feeling guilty. I started this now and haven't posted any pictures. Last time in the A4LD Diary OperaHouse complained that there were no naked trannie pics in 2 full pages of posts. So I cannot post any trannie pics, yet, but let's explore a NEW valve body.

I bought this on E-Bay, brand spanking new....pretty in pink... this is the top (or installed, bottom)

flipped - the separator plate... virgin...

Of those round things? Reinforcement plates.... hmmm wonder why the gaskets blow out on the 5R's? Possible mod ideas Brain?

Ok, so how new is it? Is this a clue?

Here is what I know as the manual valve (on the A4LD/4R/5R)

The 4R70W has 2 shift solenoids, they are paired in a single unit... I'll resist calling it a "pack".... looks like this...

the TCC solenoid is seemingly "tiny".. it sits nearby

So where is the EPC? It fits in the case! and NOT the VB. I'll show you some pictures of it and the harness next.... (Operahouse, you ok now? <g>)

I have a harness and all the solenoids, plus the temp sensor... been click testing it on the tester... trying to compare it to new.... but I do not have a NEW EPC solenoid... and FORD did make a change. Need to find out if mine is pre or post change. It click tests pretty good... the TCC is the weakest.... more pics of thos to come. And soon the valve body Mods (ON A NEW VB!)

 

[Glacier991]

Well guess what... sharp eyes may have noticed the suffix AB on the above parts. My old ones are all AA... First generation...some would not even fit (the "pack, for example") on this latest VB.... here we go (OperaHouse, you watching? <g - I love to tease/taunt my friends who have teased me>) First up.... the shift solenoid pair.. old above the new on their valve body.... notice the AA on the uppermost solenoids... and also notice their tabs would NOT fit the VB....

Here is the AB designation and full part number on the new....

But wait, you can't just go out and buy a new one and replace it, why ? The connector is different (so it is all OLD style, or all new short style on tye harness... you will replace all with new or none, in other words.... let me show you... AND in the process, show you good engineering vs less good. Before I start this, I'll remind you that solenoids are activated by grounding a circuit, not by powering it. On the old "pack" connector, you could see common power (+) and then each solenoid 1 or 2... like thus

on the new style "pack" connector:

(better pic coming)

The old style connectors were more encosed.. or had longer connector flanges may be a better way to say it... here is the TCC.. old

versus new:

Side by side

Once again AA versus AB

I do not have an "AB" EPC (yet) but here is the original one...an "AA"

and the snout end...screens and 0- rings

more to come, stay tuned....long road ahead.

 

[V8BoatBuilder]

Chris... Post 1999 the 4R70W wiring harness was a printed circuit board, pre 1999 it was still a wiring harness with plugs and wires.

Nice find on the valvebody... that was made on my birthday!

 

[Eneurb]

They actually call the wiring a "lead frame".

 

[Glacier991]

Ok.... in Feb I said a couple weeks. It is August. I'm getting close now.... I am doing my homework on the 4R70W..... should have a donor soon, but picked up a case to inspect.... want to share that with you... here it is valve body side up

Quite interesting in comparison to the A4LD and 5R55 series. The servos are all inside the valve body.... no heat shield issues. So let's go around and see what we got...

Let's start with the 2-3 accumulator... small, the big one above is the low/reverse

moving forward the low reverse servo... BIG

and forward of that the OD servo... surprisingly small..

and to it's right, the 1-2 accumulator

lastly.. IN THE CASE, we have the EPC solenoid....and it is an AB model!

Notice the SIZE of the fluid passages! AT the rear we have the parking pawl stuff... there is a steel rod that fell out, I have it, but for pics I replaced it with a skewer...

and lastly, since this is a one piece case... to get to the TC drain plug (yeah these have one) there is a rubber plug on the bellhousing portion

 

[Glacier991]

Now inside. Amazing how small the geartrain cavities in automatic transmissions are, and how similar... let's peek into the 4R70W's

Two things struck me... the size of the band anchors, and the thin-ness of the back case web...

That thing sticking up on the left is the tip of the low reverse servo.

Cases came in 2 flavors, a 2 bolt starter (the A) case and the 3 bolt (the B case)
This is an A, used in Explorers

Here is a better view of the anchors...the paired set is the low/reverse (look very much like the A4LD/5R55), the single honkin one is the OD

Ok time for some help. I have the manual that purports to explain this case tag... but I cannot decipher it, anyone help? I know that the PK numeric in the upper left is the model number, and two lines below that is the serial number (this is repeated in the bar code underneath and below it) but the 8H?. My info says "for example" a .6 sideways meant the transmission was for a 4.6 litre engine. The upright 8H means? V-8? 4WD ? and the F87P-7000? I'm curious...I know from the fact there was an AB version of the EPC solenoid in the case this is newer than older....probably 98

Now the taps? I think there are 4 pressure taps... I hope I am right... here they are... 3 up front

and one in back

lastly the rear.... notice the marks in the rear bore, I will investigate that

When you see this case again it will have been degreased, pressure washed, bores scrubbed, fluid lines blown clean, bolt holes tapped and cleaned and the case sandblasted and painted.

Ok...Next up... clutch sets, planetaries, one way clutches and "mechanical diodes" and of course, bands etc. GUTS. Stay tuned. be patient with me.

 

[V8BoatBuilder]

Sweet! Been waiting for this info.

Thanks Chris!

 

[410Fortune]

These ones have to be rebuilt too? Say it aint so!

hahahaha hopefully only once and hopefulyl only every 150+ K miles....

Geesh.

U = the man, I know all these tranny tech guys love your rebuild diary's, I just look at them with my jaw on the floor, valve body is about as deep as I go, still. hahaha

 

[V8BoatBuilder]

These ones have to be rebuilt too? Say it aint so!

Let's hope not! I'm at 130k miles, and still going stuper strong. Knock wood. The Baumann kit was a terrific addition to the trans.

But, knowing how to do a rebuild when the time comes is fantastic.

 

[410Fortune]

of course. I have a 96 4r70W with 180K miles, it still drives good, although it does hesitate a bit from N to D, but it still doesnt miss a beat on the road!