Transfer case motor problem?

[quasarsky]

putting the vehicle into 4 wheel drive high and slowing down removes the noise. so it definitely must be motor trying to go into 4wd when slowing down for whatever reason? yes no? lol sorry i'm a newb!

 

[gijoecam]

How can you tell it's the motor? Doesn't the vehicle have to be rolling for it to make the noise? Does someone hang underneath the vehicle when it's happening? I'm not understanding how the mechanic came to that conclusion. All your descriptions point elsewhere. The TCS motor is not running when it's in 4auto or 4high. It only runs when <i>shifting</i> into and out of 4low.

For the last time already: THE MOTOR DOES NOT MOVE IN 4AUTO OR 4HIGH. ENGAGING 4 HIGH IS DONE BY LOCKING THE TRANSFER CASE CLUTCH COIL. THE MOTOR ONLY MOVES WHEN ENGAGING AND DISENGAGING LOW RANGE.

With that in mind, how can it be the shifter motor? What's leading your mechanic to it? There's either a piece of the puzzle you're not sharing with us, one your mechanic is not sharing with you, or it's not the motor.

(I don't mean to sound like a jerk.... sorry if I come across that way... it's completely unintentional)

-Joe

 

[quasarsky]

well what else would sound like an electric motor whirring really fast coming from underneath the vehicle? if i slow down with the brakes but still have a lil bit of pressure on the gas until about 40 or 35 mph and then just use the brakes i don't hear the noise. if i slow down from 50 with no slight pressure on the gas, if i slow down with just brakes i hear the noise. (could it be the electric pump that pumps gas into the engine???) my rotors aren't totally smooth but my lil brother said they look fine. his rotors are in the same shape as mine. i would say its rotor noise or a abs problem but no error codes came up when hooked to a scan tool.

having the vehicle in 4wd high while slowing down with just brakes also does not cause the noise.

so you are saying engaging the transfer case clutch coil is the only thing that puts it into 4 wd high? and this is only controlled by the dash switch correct, or what locks it? so its either the transfer case clutch coil being triggered incorrectly by something, or the drive computer is messed up somehow, or something is grounding out causing the noise ?? all i am positive of is that its an electric motor sound whirring really fast coming from underneath the vehicle. and there's only one motor down there i know of, the tcs. i'll get it replaced in 2 weeks (my lil brother can't do it this weekend). first he'll check for a ground short. nah u didn't sound like a jerk. this problem is just so frustrating . it drives perfectly fine, even with the noise. i just knwo the noise can't be a good thing lol

 

[gijoecam]

See post #7 above.... and #11.... It's not the TCS motor. Don't waste your time or money.
Even if the motor was able to freewheel, you'd never hear it over the road noise at 55mph, and if the motor could freewheel AND was trying to turn, it would not shift from 4high to 4low and back when you want it to.

It's not the motor. You've got the classic symptoms of a bad u-joint or bad pinion bearing.

-Joe

 

[badgett]

Remove the transfer case shift motor. It can't whine if it's not there. Then you will know for sure. It's simple to remove. With it removed you can also tell what position the transfer case is in.(4high or auto) I'll bet the transfer case is in between the two marks. Hince the noise. If it is, turn the shaft manually with some vise grips to one or the other.

 

[quasarsky]

ok i got this information from a ford service manual dvd. found from these forums :-D. does any of this info help?

thanks gijoecam but i've asked the mechanics if its pinion or bad u joint. they said no. i will have my lil brother look at the ujoint at least (pinion if he knows how).


it does sound like from this information that the perhaps the noise i am hearing is the front driveshaft trying to engage. all the information says there are decelration sensors that detect the varying speeds of parts of the vehicle (hence when i hear it only by slowing down, if it was the pinion or ujoint i'd hear it all the time right??). i'll read this information further later. i gotta get to bed!


Transfer Case —Automatic Four Wheel Drive (A4WD)

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 km/h, the brake depressed, and the transmission must be in NEUTRAL.

The front/rear driveshaft speed sensors (Hall effect) are mounted to the transfer case and detect the speed of the front and rear driveshafts. This input is used by the generic electronic module (GEM) primarily to control A4WD operation.

The throttle position output signal is provided to the GEM from the powertrain control module (PCM). This signal is used by the GEM in controlling the A4WD clutch.

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

The digital TR sensors are located on the LH side of the transmission; these sensors inform the GEM when the transmission is in the neutral position.

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.

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.

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

System Function

Hall effect sensor monitors input and output shaft speed.

In the A4WD (C-Trac) system, the GEM varies the torque sent to the front driveline by controlling the transfer case clutch. At rest and under cruising conditions, the GEM activates the transfer case clutch a minimum duty cycle (percentage of time the clutch is turned on), which allows for the slight difference between the front and rear driveshafts which normally occurs when negotiating a corner on dry pavement. Under any of the following conditions, the GEM will increase the duty cycle in order to prevent or control slip:

Slip is detected (by using the Hall Effect Sensors)
Heavy acceleration.
Very light or zero throttle at speeds above 25 km/h (40 mph)
Feature inputs:

4WD mode switch.
Digital TR sensor.
Vehicle speed signal (transmitted from the ABS module).
Front/rear driveshaft speed sensors.
Throttle position information from the PCM.
Contact plate position inputs A, B, C, D.
Feature outputs:

Solid state clutch relay (pulse width modulated signal: grounded when relay is on, battery potential when relay is off).
A4WD indicator (ground when activated, open circuit when deactivated).
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:

4WD mode switch.
Hall effect sensors.
Contact plate position inputs A, B, C, D.
Feature outputs:

4x4 shift motor relay outputs.
Solid state clutch relay (pulse width modulated signal; grounded when relay is on, battery potential when relay is off).
4x4 HIGH cluster indicator (ground when activated, open circuit when deactivated).
When shifting into or out of LOW range, the GEM requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.

Feature inputs:

4WD mode switch.
Contact plate position inputs A, B, C, D.
Vehicle speed signal (transmitted from ABS module).
Brake input (battery voltage when brake is depressed, open circuit when not activated).
Digital TR sensor (ground when transmission is in NEUTRAL, open circuit otherwise).
Start/clutch depressed input.
Feature outputs:

4x4 shift motor relay outputs.
Cluster indicators (ground when activated, open circuit when deactivated).
Solid state clutch relay (pulse width modulated signal; grounded when relay is on, battery potential when relay is off).

 

[quasarsky]

it seems like slip is being detected for whatever reason and the noise i am hearing is the driveshaft trying to engage 4wd. ?? according to the new information i got. weird! i'm learning about cars lol .

 

[quasarsky]

Under any of the following conditions, the GEM will increase the duty cycle in order to prevent or control slip:

Slip is detected (by using the Hall Effect Sensors)
Heavy acceleration.
Very light or zero throttle at speeds above 25 km/h (40 mph)

Ha! this must be it. thats why when i use brakes it doesn't trigger it. cause its not slipping enough for it to be detected. now i just have to figure out what exactly is messed up lol

 

[quasarsky]

i mean how can i go 70 mph and not hear the noise if i slow down with the brakes or while i am accelerating to 70 mph or any speed? this has to be it! since i hear the noise at 30-35 it must be pretty messed up. perhaps its the gem switch thats messed up.

 

[gijoecam]

First, a u-joint or pinion bearing can and do make exactly the noises you describe under the exact conditions yours is doing it. I can't say definitively that it's your problem without hearing the noise, but as you've described it, that's my best guess. Even though they are rotating at all speeds, neither problem will make noise all the time.

Just trying to follow your logic: If the GEM was mistakenly calling for 4wd engagement only when you're decelerating, and you're convinced that's the case, then why would locking it into 4high make the problem disappear? You stated earlier that if you lock it into 4 high, the sound goes away, didn't you?

Finally, once again, IF YOU ARE CONVINCED IT'S THE TRANSFER CASE MOTOR, UNPLUG THE DAMN THING AND TAKE IT FOR A DRIVE!!!!! TAKE THE WHOLE MOTOR OFF FOR THAT MATTER, AND TAKE IT FOR A DRIVE!!

With no power to it, it cannot, under any circumstances, move the shift rod, WHICH DOESN'T MOVE TO ENGAGE 4HIGH ANYWAYS!!!

Under any of the following conditions, the GEM will increase the duty cycle in order to prevent or control slip:

Slip is detected (by using the Hall Effect Sensors)
Heavy acceleration.
Very light or zero throttle at speeds above 25 km/h (40 mph)

Ha! this must be it. thats why when i use brakes it doesn't trigger it. cause its not slipping enough for it to be detected. now i just have to figure out what exactly is messed up lol

What would using the brakes have to do with it?? If anything detected slip while using the brakes, it would be the ABS, not the Control Trac, and it would be pulsing the ABS, not activating the traction control. Two separate systems active at two different times.

i mean how can i go 70 mph and not hear the noise if i slow down with the brakes or while i am accelerating to 70 mph or any speed? this has to be it! since i hear the noise at 30-35 it must be pretty messed up. perhaps its the gem switch thats messed up.

Driveline components do just that. There are certain frequencies that they will make noise, and certain frequencies that they will not. Certain frequencies will cause a vibroation, others will run smooth. It's a dynamic system, and each component will generate its own set of excitations.

I surrender.... Do whatever you want... I'm throwing in the towel on this one.

 

[quasarsky]

Just trying to follow your logic: If the GEM was mistakenly calling for 4wd engagement only when you're decelerating, and you're convinced that's the case, then why would locking it into 4high make the problem disappear? You stated earlier that if you lock it into 4 high, the sound goes away, didn't you?


Because it doesn't need to call for 4 high, because its engaged lol. Does that make sense?? lol. Thanks for your help. I just hope I get this mystery fixed. So many things it could possibly be . I will post the final outcome once its found and fixed. Thanks to all .

 

[rmmiller2050]

folks I just went thru this bullshitteree with my 95 eddy with 4405 BW T/C(the odd harder to find one that costs beforeoraftertaxwholeshitloads to repair. Mycar aslo has the vacuum shifted front axle (spicer 35?) thus no outer hubs to enage.
My symptoms:
-rarely used 4wd hi or lo
-car started to disengage and emit ascending whirring noise when i backed out of gas at highway speeds( I was pretty sure it was disengaging but would reenage as soon as i reapplied foot)
- soon after this it started to hunt a gear onstart -up to not want to even go in gear and then soon after disengaged when i tried to pass car under full throttle. on a camping trip. in far southeast Oklahoma. at nite. in the dark . with bigfoot and worse - hillbillies-known to inhabit the area-and not seen a car in freaking miles.
Once we got her home:
T/C was in bad shape : shift fork ears that engage low gear were practically worn off , the nylon liners totally ground to dust. (thus the disengagement when slacking the drive train ) Typical of BW 1345. & 4405 T/C the oil pump reaction ear had worn thru the case boss and the pump spun...no pumpy/no looby....pump body (aluminium) had melted and seized to mainshaft, maaybe a log time ago thus the worn out shift fork, bushings clutch pack etc. 300.00 bucks worth of repair parts it is good to go again .
re the current issue with quasarsky's rig: The TCS does not turn fast enough even with no load to make much noise. I suspect all of his e-gadgets are fine and that his box is self destructing just as mine and all BW T/C of this series will (my car has 190k on it) . I bet his rig quits shifting soon. He needs to check metal content of T/C lube. Mine looked like liguid silver. here is the sequence of events operationally speaking when you turn de funny leetle nob on de dashingboard:
2wd: TC clutch inactive, thus no chaindrive engagemetn, no front output shaft engagement plus DS front axle is turning the DS side and spider gears and possibly the PS inboard axel /side gear and possibly the front pinion and driveline- depending on frictional loads. My car?: the front driveline does not seem to be rotating at all- but in reality the front DS wheel is driving the DS axle is driving the DS sidegear /spider set in the front differential and has got to be doing some combination of spinning the PS side inboard axle and ring/pinion. I expect that with this axle the rotation is spent in driving the spider and side gears and not turning the front driveshaft /transfer chain and gears due to inertia/friction.
4wdauto: T/C clutch is on (yes Pulse width modulated - not constant voltage/current fed to it--controlled by GEM responding to throttle pressure and , I think, the front and rear driveshaft speed sensor signal differential) . Once in 4wd auto the TC clutch/chainset becomes constantly engaged and the front diff is powered. The signal difference between the front and rear driveshaft speed sensors when exceeds a certain limit causes the vacuum powered engagement of the PS inner axle to the PS outer axle thus locking up the front driveline and securing power to both PS and DS front wheels.
4WD LOW: TC clutch in play (possibly same duty cycel control as in 4WD auto)
front axle shift motor constantly engaged- full time 4WD is obtained because diferential between speed sensors is not used to signal engagemetn of front axle shift motor(the signal may be used to modulate duty cycle?). TC shift motor moves shift shaft and shoves hi/lo gear rearward out of planetary to get yer low gear reduction.
This a nutso system with the vacuum engaged front axle.
if quasarsky is seeing no prob in 2wd and experiencing his noise in only 4wd auto (or in his car it may be he has the other axle with hubs so it would be 4wd hi) and getting no sign of engagemetn to 4WD Lo then here is my exact diagnosis:
1. I think his TC is kaput for failed oil pump, at least his shift fork is very worn- could present same symptom
2. Advice to trouble shoot ( so much truoble you wanna shoot yourself-thats where that word came from i guess);
remove TCSM , and place shift shaft in 2wd hi , rotate TCSM so it is aligned to engage shift shaft in 2wd position and reinstall motor (so shift shft does not move ) but do not reconnect wiring..then go drive and do the high speed back off the gas thing several times and see if the funny noise happens. you are essentially trying to make the hi/lo gear disengage when you slack the drive train at higher speeds( minimum of 50 mph). If this occurs then you have proven the hi/lo gear is backing out of the planetray due to wear of the shift fork- maybe even a broken fork. What you ar doing is isolating the 4wD function from the hi/lo range shift function
3. To prove that the 4wd auto (or high) works reconnect TCSM (after leaving neg wire of car's battery disconnectd for at least 15 minutes) and just jack up the rear DS wheel and shift control into 4wd hi/auto and give it enough gas to spin the rear wheel (carefully/slowly) . This should force the engagement of the front axel shift motor in less than 1/4 turn of the rear wheel. You will feel the front wheel /axle try to go places. Clunks and bumps are normal noises. If this happens you have just verified yer TC shift motor / front & rear hall sensors /front axle engageing mechanisms/TC clutch and transmission shift position sensor(PRND switch) are all working together correctly.
3. to prove 4wd lo mechanisms work (not the TCSM motor or GEm controller) take TCSM off and place shift shaft (rotate ccw to stopping point) reinstall motor but do not reconnect wires. Turn control nob to 4wd low positoin . Run +12 volt 12-14 gage wire from battery or nearer power source to large brown wire that goes to rear of TC housing (this is TC clutch power feed---just one larger brown wire --not to confuse with the three wire bundle feeding to rear speed sensor. ) This locks you mechanical shifting mechanism in to lo range position and applies clutch which will get power to front axle and rear axle and thus 4wd lo. On my car with the vacuum shifted axle the GEM must ignore the speed sensors and apply vac to the front axle shift motor. Go drive the car and tunr tight circels if it makes lotssa clangin and bucks around and goes lik e it is in a really slow gear tehnyou have sucessfully engeged 4wdlo. the humpign and bucking and claangin is due to torssional wrap up especialyif you are aon dry pavemnt and youhave full uninterupted power to TC clutch, which the GEM would noramlly cycle to allow torsion bind to dissipate. DONT do this any longer than it takes to convince you you have front axle lo range engagement. You coul be succesful with this maneuver and stillhave a very badly shot shift fork in teh TC. If you cant get 4wd lo like this it can mean :
worn or broken shift fork ( fails to retract hi/lo gear rearwrad far enough)
TC clutch shot (check ohms to case from brown wire- i forget the spec)
Front axle (spicer 35) vacuum shift motor inoperative- could be bad soleniods/fuse
maybe the transmission shift posiiton sensor is bad- this comes into play when shifting to 4wdlo and is not isolated in this test.
try the above , hope it makes a little sense and dont keep any loaded guns around

 

[gijoecam]

Keep in mind that the 95 case internals and function are a little bit different than the 98 he has. We still haven't heard back as to what the problem turned out to be.

I started a thread last week called Control Trac Technical Discussion that had some *new* discoveries in it for us.... might want to check it out and chime in if'n you've got some time....

-Joe

 

[gijoecam]

Just trying to follow your logic: If the GEM was mistakenly calling for 4wd engagement only when you're decelerating, and you're convinced that's the case, then why would locking it into 4high make the problem disappear? You stated earlier that if you lock it into 4 high, the sound goes away, didn't you?


Because it doesn't need to call for 4 high, because its engaged lol. Does that make sense?? lol.

But MECHANICALLY, there is no difference!!!! For the umpteenth time, THE SHIFT MOTOR DOES NOT TURN WHEN IN 4AUTO OR IN 4HIGH, OR WHEN SHIFTING FROM 4AUTO TO 4HIGH!!!!

Is it me, or does that look like English?? Am I typing in tongues again??? I hate it when that happens!

 

[IZwack]

But MECHANICALLY, there is no difference!!!! For the umpteenth time, THE SHIFT MOTOR DOES NOT TURN WHEN IN 4AUTO OR IN 4HIGH, OR WHEN SHIFTING FROM 4AUTO TO 4HIGH!!!!

Is it me, or does that look like English?? Am I typing in tongues again??? I hate it when that happens!

Sorry for being so late to chime in..

GIJOECAME is correct - the shift motor does not move when switching between AUTO and 4HI.

The image above outlines the shift motor's possible positions - of which there are three of them ("N"eutral is not one of the positions available from your dash switch). When the vehicle is in AUTO of 4HI, the shift motor is always pointing at "H".

If you think that the 4wd system is trying to engage when your vehicle is slowing down, then leave the dash-switch to AUTO and disconnect the shift motor (it has a huge connector) and take it for a full day's drive (you're usual drive to work or whatever) - see if it still makes that noise. Note that when you disconnect the shift motor, the 4HI and 4LO lights will blink but dont worry about that.

When the vehicle is lifted up in the air and the transfer case switch on the dash is in AUTO, the front wheels will still rotate as there is some "drag" in the transfer case.

It has been suggested before, by GIJOECAM, that this whirling may be differential related - I am thinking the same thing. I would disconnect both driveshafts and check for any latteral play in both differentials. This whirling sound could be a pinion bearing/race and/or the pinion gear not properly engaging the ring gear on the "coast" side of the teeth. The latter is usually caused by a worn out pinion bearing. This happened to my brother's '97 Explorer's rear differential and over time, it developed to a clunking when the gas pedal was released while in motion. We removed the differential from its housing and changed the pinion's bearings and races (there are two) - solved the problem.

If it is not a differential issue, the next thing I would check is the transfer case's bearings. The transfer case's casing is usually a magnesium alloy (a soft metal) and, over time and applied stress, the holes that the output shafts' bearings seat into elongate and start becoming more like ovals instead of perfect circles. So check for any latteral play on the transfer case's output flanges (the front isnt really a flange, its more like a cup because of the CV joint).

 

[quasarsky]

duplicate post - second one below lol

 

[quasarsky]

Okay!

Well it wasn't the transfer case motor nor was it the bearings or differential or anything like that!

It was the fan motor for the heat/ac blower. LOL. Well at least I was somewhat right. It was a motor lol

My lil brother checked the engine and saw a greened threaded copper wire going to the a/c thing that was broken off. It looked like a ground. He hooked it back up but we were still hearing the noise, so either the ground was so corroded it wasn't working right, or the motor was messed up from not being grounded. We disconnected the power for the motor, but left the resistor plug in (nothing to resist since no power, should be okay right?) and I haven't heard the sound since. We took it on 5 test drives last night and after we unplugged the blower motor on the 6th drive we didn't hear the noise anymore. I drove 1 1/2 hours home and no noise. I'm still getting enough heat though its just not blowing in. I don't think there's any long term negative effect from not plugging it in. Someone tell me if its otherwise.

Why I would hear the blower motor noise when I was slowing down, I have no idea? I find that highly strange. But I haven't heard the noise since, so I am pretty sure we found the culprit.

OH and I didn't feel like hooking the old transfer case motor back up since the new one is on there. Anyone want to buy a used transfer case motor for $40 bucks shipped? it's not in the best looking shape but it works fine lol

 

[IZwack]

a happy, highly unexpected ending

 

[quasarsky]

hey IZwack, do uthink it was the bearings in the blower motor that were going bad? or the motor itself? i'm still boggled why i wouldonly hear it when i slowed down.

 

[BrooklynBay]

The blower motor probably turns a little slower when you are not stepping on the accelerator pedal, because your voltage drops slightly. Try turning on all of your lights, radio, defrost, wipers, and heater. Your voltage will be even lower. Once you start to accelerate, your voltage will go up, and provide more power for the blower to turn a little faster. It's not a big difference in voltage (maybe under a volt), but it' sjust enough to make a difference.