hey all. new here. trying to help out a buddy.so ill get the background of the truck out of the way. hes got an 05 silverado 4x4 extended cab short bed. 5.3ltr v8 approx 50,000 miles.

he bought the truck brand new in 05. since hes owned it it has had a clunk under acceleration. hes brought it in a million times and some say its normal and others cant figure it out. u-joints have been ruled out.

so ive been researching this on my own as hes not much of a forum guy. i swear by them. any how ive been looking into this and have come up with a possibility.

it is a common problem that intales replaceing the yolk with a certain type. (exact name is slipping me right now). or packing the splines with grease or antiseaze.

another is the tranny fluid that is used and what should be used. the name was trac something??? (vague i know.)

from what i gather on this it appears that the axle is wrapping..ie lifting and more or less binding the driveshaft??

some have had luck with all of these methods i stated above. some say a trac bar will cure this issue.

so i turn to you all for the answer. i used to own a ford that did this exact thing and i never figured it out and since got rid of the truck because i couldnt stand the noise. so i totally understand his frustration. so what have got.

 

I have an '03 with the same noise.... Unfortunately, its a common problem that GM knows about but hasn't figured out a cure for. I asked a transmission repair shop to take a ride with me and they told me, its common, go ahead and drive it, ya not going to hurt anything, but i've learned to drive a bit differently now but every so often, it still clunks and drives me crazy. Yet my wifes '02 Avalanche with the same tranny, but she has the 5.3L VS my 4.8L, and her Av does not do it, figure that 1 out. Let me know if ya ever find anything that fixes the problem. Jim

 

Have you tried pulling the driveshaft out of the tranny and lubing it really well. It could be binding for a split second then sliding in producing the clunk.

 

Agreed - it's probably the slip yoke. All too common problem with Silverados. Some have it, some don't. Pull it out, grease it up, do it again next year.

 

Exactly what Mr_Shamrock said. I pulled the drive line out on my 06 and the yolk had dried grease built up. Just re-greased it and the thump is now gone. Ive wondered why my dads extended cab had not had the issues with 120,000 miles and my 06 single cab has.

 

thanks for the help guys. pretty much what i expected for responses after doing some more research i came across alot of this same info. i havent greased it. going to have my buddy come by this weekend to pull the shaft so i can grease it. now i read somewhere that someone used antiseaze. has anyone tried this. any advantage to it over a high quality synthetic grease? or is everyone just using grease? thanks again for the help.

 

I would just use a good high quality grease. Maybe even some marine type if you can find it.