Transmision

jlh0799 · July 21, 2004

I have an '02 Z71. I have noticed a clank in my transmission. It doesn't happen every time! It mostly happens when I have stopped at a light and then proceed to step on the gas. It takes about a second or 2 for the transmision to kick back in and when it does, it hits (like the clutch is slipping) and there is a clank! Has anyone had or heard of this problem? Thanks in advance!

I have also noticed a nocking noise on the initial startup for about 15-20 seconds. Could this just be bad gas? It doesn't do it all of the time, about 3 times a week or so. Any advice or help would be great. Thanks

chris_kucia · July 21, 2004

I have the same problem with the clank on my 00 Z71. It really drives me crazy and makes driving the truck less-than-enjoyable.

First I thought it was the parking brakes hanging.

Then, I thought it might be the clutches in the rear end (I have the Gov-loc differential).

However, I've come to the conclusion that its most likely the dreaded "driveline clunk" (do a search).

This is caused by a binding condition on the front driveshaft yoke where it interfaces to the transfer case. Apparently the splined shaft doesn't slide against the splined yoke interior. As the driveline torques, it builds tension until the binding is overcome.

There's a tsb on this. The solution is a nickel-plated yoke and using a new version of the transfer case fluid. A temporary solution is to remove the driveshaft and smear grease all over the inside of the yoke. Lasts from a few days (in my case) to a few months.

I've got a replacement yoke and new Autotrac fluid ordered. Should have it next week, but I anticipate this will solve the problem.

The good news is that the Autotrac fluid is relatively cheap ($4/qt).

The bad news is that the new yoke (with universal) runs about $145. If you aren't handy, you'll have to pay someone to put it in.

However, if your truck is still under warranty, then you can likely get it fixed under that.

The engine knock has been discussed before, but honestly I haven't paid attention to the discussion because it isn't an issue for me.