06 Rainier leaking front diff

[SoundBass]

Hi all! I have reaped a lot of info on this forum, and thought I'd register to ask questions.
My Rainier is leaking bad from the LH side of the front diff because the bearings are toast causing the CV shaft to wobble as one moves it (RH side is fine).
I bought this vehicle 2 years ago, but noticed a problem one year ago when my wife and I travelled for over 6 hours. We had got off the interstate and pulled into a plaza and made a slow, sharp turn, along with a wobble/lunging (best description I can come up with). Immediately, I thought it might be the front diff. Now, a year later, we are at a local parking lot, and the same story, only this time there is dry metal grinding/scraping. The next day I checked the level only to find rusty "grease". I topped up with 75w90, and it is quiet and behaving (for now). I figure that the gears are shot, and the bearings are toast(perhaps the case is too). I have an 04 Rainier and was hoping to use the front diff from it but the problem is that it has 4.10 gears and the 06 has 3.73.
Reading on this forum, I thought that there should be a cause to the bearing wearing out, so I jacked up the front end and spun a wheel....which caused the opposite wheel to turn backwards. The front driveshaft wouldn't rotate, so I chocks on front and rear of the rears wheels, put my foot on the brake, put the tranny in neutral and slowly released the brakes. I tried to turn the front driveshaft again, but it won't. I jacked up the RF wheel of the 04 Rainier and it turned a full rotation freely.

Question 1: am I correct in concluding that the transfer case is locked in?

Question 2: do I have to pull the (dis)connect on the RH side of the oil pan, and the intermediate shaft, before pulling the diff?

 

[Mooseman]

Hi and welcome!

1. No. The transfer case in these AWD trucks (except the TB SS) have part time AWD. Front wheels aren't engaged until it senses rear wheel slip.

2. Yes.

And if you wait a little, @m.mcmillen will be doing a write-up on how to remove the front diff and an easier way than the "normal" way out the top.

If you want to use the 4.10 front diff, you'll also have to use the 4.10 rear diff. Unfortunately, the 04 doesn't have the proper individual rear wheel sensors that the 06 requires for proper ABS and Stabilitrak operations. You could swap the gears out of the 04 and put them in the 06's caseif the are both the same size gears (8.0 or 8.6). Your speedo will be off until you get the PCM reprogrammed or tuned.

 

[SoundBass]

Hi and welcome!

1. No. The transfer case in these AWD trucks (except the TB SS) have part time AWD. Front wheels aren't engaged until it senses rear wheel slip.

Thanks for the welcome!

Sooo, my encoder motor is likely stuck? Front wheels off the ground, engine off, trans in neutral, rear wheels chocked and on the ground.....front shaft does not turn.

2. Yes.

Thanks.

And if you wait a little, @m.mcmillen will be doing a write-up on how to remove the front diff and an easier way than the "normal" way out the top.

Looking forward to it!

If you want to use the 4.10 front diff, you'll also have to use the 4.10 rear diff. Unfortunately, the 04 doesn't have the proper individual rear wheel sensors that the 06 requires for proper ABS and Stabilitrak operations. You could swap the gears out of the 04 and put them in the 06's caseif the are both the same size gears (8.0 or 8.6). Your speedo will be off until you get the PCM reprogrammed or tuned.

Nope, not going to change ratios. I might use the case from the '04 and put new guts in it....don't know yet.

 

[Mooseman]

Sooo, my encoder motor is likely stuck? Front wheels off the ground, engine off, trans in neutral, rear wheels chocked and on the ground.....front shaft does not turn.

Probably if it won't turn. Easy way to check is to pull the encoder motor.

 

[SoundBass]

Cool I will do that next week.

 

[Mektek]

Oil leaking out is not necessarily a death sentence for the front diff. As long as the 4wd is not being used there's very little load on the components and the small amount of oil that remains is adequate.
Mine was empty for several years, and when I got it I replaced the outer seal and refilled it and it's OK. No doubt there is some wear and tear after 235K mi, but the new flexible seal compensates enough for the movement that it isn't a problem.
Before you go to the major repair, try the simpler, cheaper job first.

And cv axle wobble could be caused by a bad axle - you should check that too.

 

[m.mcmillen]

@SoundBass here is the promised writeup.

Trailblazer, Envoy, 9-7X Front Differential Replacement Instructions

I have noticed lately that there has been talk of replacing the front differential with some. As these vehicles age, the likelihood of the front differential needing to be replaced will be going up, so I thought I'd share how I have replaced a couple of these, and it works pretty well. For...

gmtnation.com

 

[SoundBass]

@SoundBass here is the promised writeup.

Thanks for that! It seems like a lot less work than the GM way, or even pulling the alternator and A/C compressor. along with the brackets.

 

[SoundBass]

Well, I pulled the encoder motor, and the front driveshaft now spins when one front wheel is off the ground. I could freely rotate the gear that the motor turns but it wouldn't cause the transfer case to lock up. I put a pair of pliers on it and turned it clockwise a little more, and the driveshaft then became engaged. I found a link from back in 2012 or 2014 that shows that I had to turn it so that a roller would go up a cam. http://offroadtb.com/transfer-case-operation-nvg-226-np8/
So, everything seems to operate correctly. I even tried to turn it as far as possible clockwise, but it still easily came back to the neutral position.
I pulled the encoder motor apart and checked for broken teeth, but there were none, so I lightly added some new grease and reassembled it. Turns out, it's a Dorman. I bench-tested it with a battery, and it works in both directions. I then reinstalled it. Vehicle seems smoother now.
It's a little frustrating because I didn't FIX anything; only made sure that it (TC) is now in neutral. I saw on another thread that it was suggested that the shift rail (#10 in the diagram) may be binding, or the TC oil should be changed because the clutch pack may be sticking. I don't know the history on this vehicle, yet the oil level is up and is a nice blue colour.
I am tossing the idea around to add a couple of LEDs, one hooked backwards to the other, to the TCCM output wires to give an indication of motor activation and direction. Also, considering running a volt meter (DVOM) to the sensor wires to see of there is a problem.

 

[TJBaker57]

Also, considering running a volt meter (DVOM) to the sensor wires to see of there is a problem.

It just so happens I recently posted some pics and a couple videos where I did just this at the end of this thread...

TC Motor

TC motor connected but not installed. Turned switch from 2WD to 4WD, motor turned more than I would have expected (120deg ?) lite on 2WD stayed steady, lite on 4WD blinked. Flashed long enough that I didn't think it would stop. Turning back to 2WD, motor backed up a bit, but then went forward...

gmtnation.com

 

[SoundBass]

Thanks! Since mine is AWD, it makes it's own decisions, and I just want to see what is going on.

 

[Mooseman]

Argh. Dorman is junk for anything electrical. I'd be seeking a replacement.

 

[TJBaker57]

Since mine is AWD, it makes it's own decisions, and I just want to see what is going on.

My curiosity is peaked. I haven't access to service literature for those. Does the encoder motor not have a position sensor then?

 

[Mooseman]

Yes it does.

 

[TJBaker57]

Aha! So in theory one could still monitor the shift motor position/location even though there are no user selectable modes. Granted, it would take some experience and or testing to turn those observed voltages into something potentially useful in diagnosing a trouble. I wonder if the encoders in these also suffer the wear-in of the resistive material that the 4WD models do.

I see the electric shift motor brake is no longer needed in these AWD models.

 

[SoundBass]

I replaced my front diff following m.mcmillen's way but it took me way too long! The RH CV shaft wouldn't come so I removed the inter-connect, brought it to the bench and drove the stub out.
There was not enough room to remove the diff through the bottom so I reinstalled the front diff-bolt and hooked the ratchet strap to it, and after pulling the bottom over the diff basically fell out.
Here is a picture of the failed bearing. The LH shaft support bearing is toast also.

 

[SoundBass]

Part of my lengthy time also included difficulty inserting the LH shaft. I had replaced both diff seals but they were the same part number (for the RH side of the diff.) It took me a while to figure this out, but, I got the correct seal for the LH side, installed it, and the shaft slipped right in.

 

[SoundBass]

Here is the link to m.mcmillen's thread on how to pull the diff out the bottom

Trailblazer, Envoy, 9-7X Front Differential Replacement Instructions

I have noticed lately that there has been talk of replacing the front differential with some. As these vehicles age, the likelihood of the front differential needing to be replaced will be going up, so I thought I'd share how I have replaced a couple of these, and it works pretty well. For...

gmtnation.com

 

[TollKeeper]

Whats the story on your 04 Rainier? Is it just a parts truck?

 

[SoundBass]

Yes, it is now. A month ago I bought another '04 Rainier, which also happens to be the same colour as my '06 Rainier...white. The burgundy '04 supplied a bunch of parta so that the white '04 could pass a safety check(for licenseing). The burgundy '04 was in an accident and was written off.

 

[SoundBass]

Well, here I am back again. Last week I noticed that on a quick, sharp turn (one full steering wheel rotation or more) the vehicle would slow down, be difficult to move, would sort of lunge. Today, I chocked the back wheels and engaged the Ebrake, put the trans in neutral, and jacked up a front wheel and tried to spin it but it wouldn't go more than a slight rotation. I pulled the TC motor and noticed that it seemed to be in the "engage" position. I pulled the encoder sensor off of it's location, rotated the inside circle while measuring the resistance (900 ohms, and rising to 1,400 ohms). Seems fine to me. Using a couple of jumper wires, I tried to run the motor but it would only move about one tooths worth and stop...did it in both directions. Thankfully, I have my old '04 Rainier, and took the encoder motor from it. I ran the motor until it seemed to be lined up correctly with the shaft, and then installed the motor, and went for a drive around the block. It still acted up. Removed the motor, reclocked, moved the TC shaft to the 2WD position and tried again.Used the info that I found here.... https://gmtnation.com/forums/threads/4wd-glitch.21144/#post-600150 ... which linked to this >>>>>> https://gearsmagazine.com/resources/issues/130543208322118000.pdf Same story. 3rd times a charm, but this time I removed the #8 fuse before going around the block. No problem now, except that the dash light is on.
I am considering putting in a single pole, double throw switch inside the vehicle to power the motor in and out of AWD, when I want. Also, I am wondering if the TCCM has a stuck relay, or MOSFET or SSR, or somesuch. Any ideas?
Would the TCCM from my old 04 Rainier work in the '06 Rainier without problems?
TIA.
Adding all this to this thread just in case someone else needs this info.

 

[TJBaker57]

pulled the encoder sensor off of it's location, rotated the inside circle while measuring the resistance (900 ohms, and rising to 1,400 ohms).

Did you ever run those wires you were going to run to monitor the encoder signal voltage?? You can tap into them at the TCCM or the X101 connector. Easier to have them already inside the cabin though.

 

[Mooseman]

Would the TCCM from my old 04 Rainier work in the '06 Rainier without problems?

Yes.

The problem with your switch solution would be that it won't hold in the AWD position. You would push the button and it would engage the front wheels but would slowly return to the 2wd position. There is no brake in the encoder motor like in the 4x4 version to hold it there.

I wonder if your TCCM is engaging your front wheels continuously because of a difference between the front and rear wheel speeds. I've seen a couple of members have this problem because they had slightly different tires front/back or one pair was more worn than the other.

 

[SoundBass]

Did you ever run those wires you were going to run to monitor the encoder signal voltage?? You can tap into them at the TCCM or the X101 connector. Easier to have them already inside the cabin though.

Not yet. Thanks for the idea of doing it inside the vehicle.

Yes.

The problem with your switch solution would be that it won't hold in the AWD position. You would push the button and it would engage the front wheels but would slowly return to the 2wd position. There is no brake in the encoder motor like in the 4x4 version to hold it there.

I wonder if your TCCM is engaging your front wheels continuously because of a difference between the front and rear wheel speeds. I've seen a couple of members have this problem because they had slightly different tires front/back or one pair was more worn than the other.

Shoot, I thought I had a bandaid repair.

All the tires are the same and were new at the same time, with equal distance on each.
Oh! I just remembered that I have a few codes, and was wondering if they might have an impact on the TCCM.
C0050 RR wheel speed sensor
C0455 steering wheel position
C0244 PWM del torque fault
My son had looked into these whilst we were on a drive from Port Huron, MI to Hudson, SD, and back, a couple of weeks ago. Apparently they could be inter-related (power source, I believe?)

 

[TJBaker57]

To me those codes don't seem related to your 4WD issue. They seem like they would affect the traction control and ABS systems.

The TCCM uses its own propshaft speed sensors for 4WD operations so the C0050 shouldn't matter to the 4WD system.

And your bandaid solution would require a DPDT switch not a SPDT to be able to reverse the motor direction.

 

[TollKeeper]

With it being an 06, and having a YAW sensor, it will also use the ABS sensor inputs for the AWD system (Stabilitrac).

They are all related. I imagine once you get those fixed, you should be good.

 

[TJBaker57]

With it being an 06, and having a YAW sensor, it will also use the ABS sensor inputs for the AWD system (Stabilitrac).

They are all related. I imagine once you get those fixed, you should be good.

Interesting!! How does the TCCM become aware of this input? I see no wiring between the TCCM and EBCM.

 

[TollKeeper]

I read an article on it a couple weeks ago, but I will be damned if I cant find it.

From memory (which is faulty!), its all a shared data path, in regards to speed, steering wheel input, wheel speed, even temperature, and a few other inputs, to use a predictive methodology in what it expects to see happen.

On a buddys 07 Envoy I recently repaired.. He had a bad ABS sensor, which turned on the stabilitrac, ABS, and a MIL light.

I was able to get his MIL, ABS and stabilitrac light to turn off with the replacement of the wheel bearing, but his Stabilitrac light turns back on because of a bad clock spring. Since the clock spring is not related to the YAW sensor, I was confused.

He was going to have a independent shop replace those sensors. I hate working on steering columns!

 

[TJBaker57]

My 02 Trailblazer doesn't have ony of these things but my 05 Yukon does. I imagine the systems are at least somewhat similar.

 

[SoundBass]

.

And your bandaid solution would require a DPDT switch not a SPDT to be able to reverse the motor direction.

Yes, you're right. I thought about that on a 130 mile round trip today, and realized that.

Had no problem with the fuse pulled so far.

With it being an 06, and having a YAW sensor, it will also use the ABS sensor inputs for the AWD system (Stabilitrac).

They are all related. I imagine once you get those fixed, you should be good.

My Stabilitrac does come on when I get on it when entering a freeway (such a nuisance).
I guess I will look into C0050 code first.

 

[TollKeeper]

So under normal driving the Stabilitrac light is not on?

Its only when a accumulation of lights on that it should be creating the TC bind. You dont have the Stabilitrac, with ABS, light on, so that negates that.

Sounds like you should focus on the TC.

But I would still get those codes corrected.

 

[SoundBass]

Normally, the Stabilitrac light is off.

Thanks TollKeeper.