Rear-end thunk on take off

Rear-end thunk on take off

Postby Boardbanger [OP] » July 15th 2012, 3:16pm

I have a 2003 Safari XLT AWD with 49K miles which has developed a thunk sound which seems to originate from the rear end. My first thought is that there is something loose in the suspension as the sound happens on take off from a stop especially if I've been braking going down hill to a stop. I took it into my mechanic thinking there is a worn bushing or the like, and we put it up on a lift and he pried and poked with a bar and couldn't find anything that was obviously worn or loose. He also drove it and would stop and then with the brakes applied accelerated an sometimes would get the thunk. He thought it might be a worn engine mount but they are also sound. It seems to be most pronounced when I've either stopped going down hill or stopped abruptly which could pull the axle back a bit. My theory is that when I pull up to a stop something is loose or worn in the rear end attachment to the body and that the axle gets pulled back by the brakes and when I accelerate the axle moves back to where it was making the thunk in so doing. My mechanic who is highly reputed actually suggested that I check a Safari forum for insight.

If anyone has had and solved this problem or has an inkling about it I'd be grateful for any assistance or advice.
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Re: Rear-end thunk on take off

Postby chevymaher » July 15th 2012, 3:21pm

It is a common problem with these vans on this forum.
Mine did it. Rebuilt the rear end still did it.
Replaced rear transmission bushing, never did it again.
Wiggle the driveshaft where it enters the tranny and check it for play.
I am sure other things can cause it sticking brakes etc.
But for me that was it without a doubt.

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Re: Rear-end thunk on take off

Postby Boardbanger [OP] » July 16th 2012, 11:30pm

Thanks very much. Will take it in and have my guy look at the bushing.
Jbt
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Re: Rear-end thunk on take off

Postby Corsemoto » July 17th 2012, 12:38am

Something cheap to try is to remove rear driveshaft and lube the splines well with transfer case fluid and reinstall. Same goes for front driveshaft only clean the old decayed grease off of the splines and use a quality grease. Both of these are fairly easy jobs.
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