Need Help: Drivetrain Whine, Slipping in tight turns

[bentcipher]

Hey everyone…

Got a little bit of a problem with my ’01 Vx with 95k miles in unfamiliar territory – searched the forum and it appears my issue is originating from within the drivetrain but I can’t get anything definitive.

SYMPTOMS:
The truck is “jumpy” in tight turns going slowly forward or backwards (whether left or right) – that is, when the steering wheel is locked in to the right or left, throttle pedal travel does not correspond to the usual rate of vehicle acceleration. It momentarily hesitates, as if you’re stepping on the brakes, then as it slightly lunges forward as if you release the brake, then brake again… so it’s rocking back and forth, and other times it feels like it “slipping” or similar sensation when ABS is kicking in. Feels very similar as if I had 4lo engaged and in tight turn but a bit more forceful in lunges which ruled traction-related issues out. Other than that, I don’t hear anything abnormal or hear/feel any grinding.

At the same time, I noticed another abnormality. The drivetrain (unsure where exactly noise is coming from) is A LOT louder than it used to be, especially as you’re coming to a stop. It’s exactly the same whine that you hear coming from your drivetrain except a lot louder. The vehicle does not feel different however, may slightly “heavier” if anything..

This may or may not be related but the Vx was towed about a month ago (this just started happening a week ago), which was done by a mistake and when the driver brought it back I asked him how he got the truck on his flat bed to which he replied that he used WD40 spray on the tires to drag it up from a asphalted parking lot onto a metal flatbed.

I’m looking for guidance on which component I need to start looking at (diffs, tranny, t/c, etc..) to resolve the jumping and the whine.

Also, I’d like to know if this is related to the “towing” method truck driver used few weeks before the problem surfaced.

Thank you all.

[circmand]

those threads sound similar to what you are describing. I hope this helps there are several suggestions

[4X4 UFO]

bentcipher,
I can't address all of your symptoms, but the whine on deceleration sounds a lot like the TOD does when all the tires are not the same circumference. I tried running rear tires that had about 3/32 less tread depth than the fronts, and it caused a loud driveline whine on deceleration. When I put an evenly worn set of tires on all the way around, the whine disappeared.

Randy

[bentcipher]

Thanks both for the reply... I checked the diesel sound search results... not it. I'll read it in more detail but so far the symptoms are different. The sound itself is an even whine that stays at about same pitch no matter what speed, acceleration, coasting, etc... also, this is not motor related. My gut tells me it's probably the differential but don't have enough experience to know for sure.

Oh, and it's definitely not the tires or traction related, same "whine" occurs whether I'm at 2 mph, 20mph, or 40mph... can't hear the rest due to wind noise.

As far as slipping/jumpiness in tight turns - I had this truck for about 3 years now and pretty familiar with its eccentricities and character traits, especially in tight turns, on/off pavement, good/bad tires. What I'm experiencing now is very dissimilar in a feel and sound.

Thank you both for the input.

[Solitude]

It is still an all wheel drive vehicle.... maybe your turn is a bit too tight for the speed

[bentcipher]

Well.. I think the culprit here is the front axle. For now, I'm ruling transmission and T/C out as I'm not able to establish a relationship between the symptoms and the transmission or gearing itself. The symptoms persist whether I'm in gear or coasting in neutral, forward or reverse, slow or fast, in 4lo or 2wd, etc..

I'm going to start with changing fluid both front and back and see where that takes me. Will post results as soon as I have them...

[tom4bren]

"Also, I’d like to know if this is related to the “towing” method truck driver used few weeks before the problem surfaced."

Entirely possible. I would definitely check with the company to see if they will have the VX evaluated at a garage of your choice (not theirs).

[MSHardeman]

I was actually thinking about the towing issue during my morning coffee (hey, it just popped in my head) and I wouldn't think that dragging ANY car across the asphalt would be good. It would put stress on all the gears along the drive line (transmission, transfer case, differentials) and could throw something out of whack.

[TheGanzman]

I was actually thinking about the towing issue during my morning coffee (hey, it just popped in my head) and I wouldn't think that dragging ANY car across the asphalt would be good. It would put stress on all the gears along the drive line (transmission, transfer case, differentials) and could throw something out of whack.

Agreed - kinda like throwing it in "Park" while you're still rolling 5mph...

[bentcipher]

Ehh, no go guys. I called the AAMCO shop here in town and they said it is actually a pretty common practice to drag up a vehicle on the flatbed whenever they cannot get it out of PARK. They said that it is very unlikely for it to affect anything and doesn't hurt gearing or anything else. They added that the only mechanism that could be affected, if any, is the Park mechanism within the transmission... so they said that if that doesn't work in any way (i.e. stuck in PARK, can't get into PARK, etc) then I might have something but other than that it is probably coincidental.

Now, as far as my symptoms, their rep stated that it could be just that I need to service my front axle. He said that in all wheel drive vehicles, there are "clutch disks" within the axle that compensate for wheel travel in turns as the total distance traveled by each of the front wheels is different (i.e. inside wheel travels less distance than the outside wheel in turns) and when you get low on gear oil, if it is broken down and is no longer able to properly lubricated axle components then you would get what he called "shudder" effect.

So boys and girls, I'm off to change that oil.... !

[bentcipher]

No cheese... looks like that didn't affect the noise, nor did it affect the "shudder"...

Did some more reading and starting to fear that this a little more serious than a fluid change

[etlsport]

try pulling the fuse for your ABS out and see if the problem occurs still (its the one show being pulled in this photo, dont mind the ghetto-rigged relay at the bottom )


if it goes away with your abs disabled you can guess its related to the abs... not sure if that would be the issue, but its quick and easy and will help you rule out another possibility

[tom4bren]

"They said that it is very unlikely for it to affect anything"

I wouldn't have expected them to reply with anything less since they are potentially liable for some very expensive tranny work.

[bentcipher]

Alright, so changing gear oil didn't really do much. The truck feels livelier but still has the whine and shuddering in turns.

After doing some probing I noticed two things I didn't quite take into account before... not sure if that helps:
1. The whine comes through the gear shifter and can almost be felt if I have my hand resting on the shifter. Transfer Case maybe?


2. The shuddering is not constant... it's more timed, occuring as the turn is made almost as if something is turning and everytime it passes a particular spot it shudders - yeah, I know, sounds like pinion gear related.. crap

P.S.
Etl: I did pull the fuse - no change.
Tom: the tranny shop I thought was pretty unbiased but if you have another specialist I'd be willing to talk to them!

[tom4bren]

"if you have another specialist I'd be willing to talk to them!"

Not really - just hate the thought of dragging a vehicle across the ground, it's bound to cause problems.

"the Vx was towed about a month ago ... which was done by a mistake"

BTW, how do you accidentally tow a vehicle?

Have you checked your CV boots? CV troubles usually sound more like clicking & you mentioned whine/vibration (but anything is possible).

Tom