Shuddering and Shaking on '03 TB A4wd

[lanman78]

Hello All!! I have read several posts here and am happy to be a new member.

I have been having a strange problem lately. When I am driving usually less than 30 MPH under slow acceleration, I sometimes get a loud shuddering coming from somewhere in the front-end. This shuddering can be heard and felt very distinctly. The only way to get it to stop is to slow to a slow roll on the side of the road and the problem subsides. 3 of the last 4 times have been in A4WD, but the last time was in 2WD. Any help would be greatly appreciated!!!

lanman78

[the roadie]

3 of the last 4 times have been in A4WD, but the last time was in 2WD. Welcome! Are you on dry pavement? If so, what benefit do you feel you get from running in A4WD? You might have clutch binding or an incipient failure in the transfer case - how many miles on it and have you ever changed the fluid?

[bullethole]

Had something similar at 60k. Only did it in awd. Changed the transfer case fluid and it went away.

[lanman78]

Most of the roads in the areas where I drive regularly switch from dry pavement to loose gravel. I find that it usually is easier to just leave it in A4WD rather than switching back and forth. My TB has 70k miles and I bought it 6 months ago. I haven't changed the fluid yet (I guess I assumed the dealer did that when they "went through" the vehicle prior to sale), but I will try that first thing tomorrow and see if that resolves it. Thanks "the roadie" and "bullethole" for the posts. You have been very helpful!

[the roadie]

...I guess I assumed the dealer did that when they "went through" the vehicle prior to sale...Too late now, but if I was buying a used vehicle and the sales scum claimed that sort of thing, I'd demand to see a copy of the work order and checklist that they performed.

"Going through" a vehicle could imply they did nothing more than search the seats and ashtrays for left-over coins and bubblegum. :D :D :D

[MTPockets]

Yes, like roadie says, you can almost guarantee the selling dealership did nothing aside from *maybe* an engine oil change. I'm a little over the top on this :crazy:, but on an '03, I would change every fluid possible at this point. BTW- your transfer case needs GM's auto-trak II oil. No aftermarket equivelants exist at this point.

Joel

[MichEnvoyBoy]

Hello All!! I have read several posts here and am happy to be a new member.

I have been having a strange problem lately. When I am driving usually less than 30 MPH under slow acceleration, I sometimes get a loud shuddering coming from somewhere in the front-end. This shuddering can be heard and felt very distinctly. The only way to get it to stop is to slow to a slow roll on the side of the road and the problem subsides. 3 of the last 4 times have been in A4WD, but the last time was in 2WD. Any help would be greatly appreciated!!!

lanman78

EXACTLY the problem Im having on my 02 Envoy with 89,000 miles. It as always occurred to me in 2HI so Im assuming it has nothing to do with the drivetrain. Plus it sounds to be coming from the right side of the truck.:confused:

[lanman78]

I have discovered the problem (at least the cause of the problem) I drove the vehicle to see if changing the transfer case fluid would do the trick. The noise still existed, just not at loud. I checked the front axle oil level and to my surprise, the oil smelled extremely bad and was a little low. I drained it and refilled it. I noticed that the oil was milky looking and would have to say that water had gotten its way in. After the change, no more shuddering or racket can be heard. The long term damage is my only concern for now.....

[MTPockets]

The front and rear diff oils, like any gear oil do smell horrible right out of the bottle. Either way- it's a good plan to swap out of the drivetrain oils at this point. Check the vent hose just above the fill port on the front diff. Make sure the hose didn't pop off. You will get water in there if the hose is off. Also make sure the vent hose is not plugged. Save that old front diff oil in a clear bottle to present to who ever you purchased from!!

Joel

[lanman78]

Here is an update on the shuddering problem:

I changed all the oils and all seemed well for about 500 miles. Then the same thing started happening again. A local mechanic suggested the encoder and sensors needed replacing. He believes the problem to be the encoder not being able to control the shifting in and out of 4x4. He might be right, but it just doesn't sound like the vehicle is trying to shift into 4x4 when it happens. Maybe it is a coincidence, but when I go over a bump or around a bumpy curve, it seems to be a lot more likely to happen. Can anyone tell me what else might be involved? Is there anything other than just gears and bearings in the front differential...such as some sort of limited slip or something? Any help at this point would be appreciated....

[Jozuah]

Hello All!! I have read several posts here and am happy to be a new member.

I have been having a strange problem lately. When I am driving usually less than 30 MPH under slow acceleration, I sometimes get a loud shuddering coming from somewhere in the front-end. This shuddering can be heard and felt very distinctly. The only way to get it to stop is to slow to a slow roll on the side of the road and the problem subsides. 3 of the last 4 times have been in A4WD, but the last time was in 2WD. Any help would be greatly appreciated!!!

lanman78

hey, if this happens again look at the 4WD selector on the dash and see if the light is ON at all,, if its not then you will possibly notice the N for neutral VERY dimly lit. it this is the case that exact thing was happening to me also.
Xfer case dropped out of gear at 70 MPH on I-480 to HWY-6 for you local drivers. and i had to stop and switch the thing back to 2WD . i talk to the place (not mentioned) i got the fluid changed and we found that they used DexIII instead of autotrackII. they sent ti to the dealer for me and changed the fluid there after flushing the Xfer case with what seemed like 10 gallons of fluid (till it wasent red any more) its back to normal and i havea guarenteed Xfer case till 100K from the iffy-lube place that did it *hint*
check the light when this happens again OR every time you start the truck.
Josh

[the roadie]

Is there anything other than just gears and bearings in the front differential...such as some sort of limited slip or something? Any help at this point would be appreciated....The front diff has zero limited slip parts. No clutch packs. Nothing but gears and a disconnect assembly so the shaft from the transfer case to the front diff won't spin wastefully while in 2WD.

Has anyone jacked up the front and spun the tires to check the CV joints for binding? While the front is supported, jack up one lower a-frame at a time to compress the suspension and check the CV joints at different angles.

[lanman78]

I'll check the CV joints over the weekend. Does the front axle disconnect receive it's signal to disconnect from the selector switch? I ask because about 5k miles ago, I noticed the symptoms associated with the switch going bad. The problem went away to be replaced with a seemingly much worse one. I don't know how the disconnect is accomplished, but if the disconnect is getting mixed signals from the switch (or wherever) it would explain the location (more on the right side of the axle) and the fact that the vehicle is mostly in 2hi (nearly 100% recently) when the problem occurs.

I also have noticed that the switch is locked on 2hi with a solid light when the problem occurs.

Thanks for the info!!

[the roadie]

Does the front axle disconnect receive it's signal to disconnect from the selector switch?It does, in a typically roundabout way through the encoder motor. Nothing goes straight from a switch to the servos involved in this vehicle - there's always a module or computer involved so errors can be detected and communicated. While you have the front supported on jack stands, and you're spinning tires to feel the CV joints, also look at the driveshaft from the transfer case to the front differential to see if its turning. If the splined disconnect failed and is mechanically frozen in the engaged position, that driveshaft will be turning when it shouldn't be.

[rbarrios]

isnt DexIII tranny fluid?
Still, that unmentionable Spiffy Lube place.... heard so many stories...

[Jozuah]

yes dex III is tranny fluid, however theres some Xfer cases that use DEXIII for them and standard shift trannys that do too ,,

ok you broke my arm, JIFFY LUBE !!! !


H8 Jiphie Lub <-- my attempt to be hip using Leet Talk and i have no idea what that even is LOL