Clunk in the Suburban Driveline

2003 Suburban with 5.3 flexfuel. Tranny was replaced at 86K and have about 30K on new tranny. Noticed lately a driveline clunk. Was thinking ujoint but didn’t see anything when I crawled under and sitting in the driveway shifting from D to R not noticeable. Also no vibration noticed from driveshft while running. Happens when I slow down from 55mph to make a corner. Not sure on exact speed but in the 20-30mph area. Clunk happens as you accelerate again. Doesn’t happen every time. Up shifting from a stop sign seems normal and no clunk is noticed. Trumar or others any thoughts?

Transfer cases on those year class models are known for some issues

Contact B&H Auto 281-3362 here in town and have them check it out on a test drive.

Tell them Jeff sent you

Does the clunk occur as you let off of the gas and prior to cornering or does it occur as you begin to corner? Since you stated that the clunk happens when you are slowing for a corner and that it doesn’t occur when you accelerate from a stop sign I would suspect a wheel end or suspension issue if the clunk occurs when you begin to corner.
also is the suburban 2wd or 4wd?

differentials are very common in those to! just rebuilt a front diff. in a tahoe yesterday

my suburban clunks on the up shift when its hot.. and then you slow down, say getting off the freeway, and at a stop light,, so from free way to intown driving.. and its starts subtle.. but it can jerk the crap out of you.. its when you up shift..and again. when the tranny is heated.. NEVER IN THE WINTER.. ever..

The clunk occurs after the cornering and as you start to accelerate again on the straight. It is a 4wd LT. This is running in 2WD. The transfer case fluid and seal was redone with the new tranny.

+1 on B&H. Great shop.

I have a 2002 silverado and I just got used to the “clunk”. They have terrible slip yokes in them that get sloppy (doesn’t hurt anything, just makes a clunk). If I get bored, I drop the driveline and pack it pull of grease and re-intall. It creates a cushion to keep the clunk from occuring. The alternate is replacing the factory slip yoke with a $600 nickel one. That may be what you are hearing. One way to tell is come up to a stop, and do a hard/fast stop, then accelerate. That will usually produce the tell tale slip yoke “clunk”.

They just had an artical on this in Popular Mech. Could be the boots on you engine mounts are bad and need to be replaced. It allows you engine to move a bit being it isn’t stabilized by the rubber pads anymore. Makes a clunking noise on turns and accelleration and fast stops. They said it’s a pretty cheap fix. Not sure it’s whats going on there but sounds kind of like it.

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I have a 2002 silverado and I just got used to the “clunk”. They have terrible slip yokes in them that get sloppy (doesn’t hurt anything, just makes a clunk). If I get bored, I drop the driveline and pack it pull of grease and re-intall. It creates a cushion to keep the clunk from occuring. The alternate is replacing the factory slip yoke with a $600 nickel one. That may be what you are hearing. One way to tell is come up to a stop, and do a hard/fast stop, then accelerate. That will usually produce the tell tale slip yoke “clunk”.

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X2, and I agree with trumar, have a professional look at it. It could really be any number of things.

Thanks for the opinions and options. Few more weeks and I’ll be able to get a day off to get it looked at.

I’d replace U joints… Not that pricey and easy to do… Mine went around 100K on my yukon…

I agree with WalleyeHunter. My 04 Silverado make the same noise. I worked for a GM dealer for a year or so and my lead tech confirmed the slip yoke. I never got around to replacing it before I left, not a major issue.

guys I was also hoping that you would help diagnose my clunk in my Suburban as well.. it clunks on the up shift.. when the tranny gets hot.. I MEAN CLUNK!!!