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Virtual Wrench
Virtual Wrench, Master Auto Mechanic
Category: Transmissions
Satisfied Customers: 14620
Experience:  35+ years experience transmission repair
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I have a 2005 GMC Savana that has driveline vibration.

Customer Question

I have a 2005 GMC Savana that has driveline vibration.
Submitted: 2 years ago.
Category: Transmissions
Customer: replied 2 years ago.
Here's the bill I just paid with the mechanics comments
Expert:  Virtual Wrench replied 2 years ago.
Hello,
If the vibration left after the front diff was rebuilt/replaced and came back then it sure as hell aint the tires like they mentioned!
It's real hard for me to pinpoint the exact cause for obvious reasons (i cant drive it or test anything) but i will say that the u-joints on the driveshaft are VERY common to cause this vibration and they get over looked all the time and tend to steer mechanics away from them to other drive train areas like you have experienced.
So what i'm trying to say is that if it was a quart low on fluid like you mentioned it sure as heck can be a differential issue again, but there is also a real good possibility that the u-joints are to blame and possibly is a coincidence that they show up bad now and not then, but the whole read on that bill was very vague and lead me to think (just by his wording) that he is fishing for answers and doesnt want to accept that it may have damaged the diff from being low.
As hard and costly as it may be, i really do advise to have another shop get involved with diagnostics on this just to get a better idea of what all has happened. I keep going back to the driveline u-joints because of all the times we have run into this on the Savanna and really think they may play a part in this.
I sincerely ***** ***** you the best on this and really hope it gets cleared up.
Best wishes my friend!
Larry
If you are satisfied with my service please use the required rating for me to receive credit for working with you.
Customer: replied 2 years ago.
would a driveshaft balance and u joint replacement be a good first step? Seems like it might be the cheapest...
Expert:  Virtual Wrench replied 2 years ago.
Hi,
How many miles are on it please?
Customer: replied 2 years ago.
87000
Expert:  Virtual Wrench replied 2 years ago.
Thanks,
That's a bit low, usually they start acting up around 100K but thats close enough to have the shaft pulled and joints inspected and have the shaft balanced. Another thing that i have seen is a balancing weight can come off the shaft, rare but it does happen.
Look around locally for a driveline specialty shop and no body else because they are most qualified to handle any driveline vibration and if its not the shaft or joints, they sure will be more precise in their diagnoses than that shop was.
If you were in Denver i could tell you an excellent shop :-)
Take care now and it was a pleasure to work with you.
Larry
Customer: replied 2 years ago.
I have only owned it about two years. It had a bad vibration when stopping when I bought it. I took it to a local shop and he had to rebuild the transfer case. The yoke was scored, the bearing was seized in place and there was no fluid. He replaced the output, put in a new bearing and seal and serviced it. It was ok for about 5k miles. On the way back from Maryland to Oklahoma it started smelling like burnt oil. I took it back to him and he couldn't see anything leaking so he said the transmission was getting hot and installed a cooler. On the way to Iowa it started to smell again. The front diff was pouring out fluid that was hitting the exhaust and burning....thus the smell. In Kansas City the vibration started and built until I had to drive 45mph to keep it from feeling like it was coming apart. The passenger side axle was slipped out of the front diff and the diff was full of shavings. An axle shop in Des Moines pulled it in and replaced the front differential. After driving it the vibration was still there. The yoke on the transfer case was again scored, bearing was gone, fluid was less than a quart and the seal burnt up. They replaced seal, bearing and serviced and it ran down the road smooth as silk. Within 200 miles it began to buzz again. By the time I got home the front diff was leaking, axle was popped back out and the vibration was pretty intense.
Customer: replied 2 years ago.
GMC shop here did the work on the receipt I just sent you. Their mechanic seemed a little at a loss....
Expert:  Virtual Wrench replied 2 years ago.
Wow....scratch the driveshaft and u joint theory!
Now i'm thinking something is wrong inside the t-case and is telescoping down line to the diff, if this all started with bearing failure in the t-case. Once it starts at the t-case it throws everything down line way out of sync...man do i ever wish i could look at this because it has my mind spinning thinking about the root cause of all this but it really does sound like it starts with the t-case.
Like i mentioned have a driveline specialty shop get their hands on it and flood them with all the REALLY GOOD info that you gave me and i'm sure they will be able to pinpoint it for you.......i feel bad because i'm at a loss for words and its so frustrating when i cant be there but i hope i have at least helped some.
I will call driveline industries here in Denver and talk to the guy i always use and try to get something from him for you. I wont give up that easy. It may take a couple of days but your question always remains open here even after you rate my service today so i WILL be back in touch with you. I promise.
Larry
Expert:  Virtual Wrench replied 2 years ago.
Hi,
I left him a message and did some searching and found an interesting article that i think will shed some light on the t-case as i suspected.
http://www.gmtruckclub.com/forum/threads/2004-savana-awd-transfer-case-problems.36295/