Not finding the best data out there. 2006 base model, 143,000 miles. Takes off smooth, shifts smooth. At speeds over 45 mph, if I let off the gas and coast, it will clunk when I re apply the gas. What's going on?

 

U-Joint or CV Joint? Or front diff bushing?

 

reach in and turn the driveshafts back n forth, feel the play in the joints?

 

If it is not a U Joint (and they make a bunch of noise when they get tired) then....
Drive train slop, common in every vehicle made with a Trans, T Case, Front & Rear Diffs, and half shafts up front, every GM 4X4 I have owned did it in one fashion or another. All that-drive train takes a while to load and unload.

You let off the throttle, the drive-train unloads TQ as the Trans goes into coast, when you apply the throttle again the clunk is caused by the re-load of TQ catching up with all the components.

 

Eventually that slop will culminate into something exploding apart I'm sure. My mechanic said it was ok too. Weird that it just started happening.

 

im at 63000,never feel any whatever.
you r at 143000, stuff is worn and you can find it by looking.
can be play in diff gears too,probably. just wiggle the shafts and you will know.

 

Mine has been that way as long as I have had it. Like Doc says, every 4x4 does it to keep you from torquing the system apart. In 175,00 miles of doing it, I have never had an issue. It's no worse now than it was 9 years ago.

 

excessive? who decides?. the svc manual says ex backlash clunk is caused by worn parts. anything in the diff.
the 2 h3 ive driven to 63000 show zero clunk and i feel no play in the diffs. high miles would wear the diff gears/parts and cause it.
you can live with it till it drives you nuts!, then fix it.
new, low mileage should not clunk imo.

 

Mine clunks the same way, however it also clunks when I begin a turn from a stop. same issue probably?

 

when i hear turn, anything, i think u r in lock mode??