Clunk when starting from a stop.

[Brewcity]

Hey guys...I noticed today that when I stop at a light or sign, then start again...I have a clunk from what seems to be the rear. It feels like the rear drum brakes are slow to release or something...and I hear a faint clunk sound. Then its gone until I come to a complete stop again.
Any idea what might be causing this?
Thanks for the help!

 

[_Dylan_]

check the ujoints?

 

[BattelWagun]

Slip yoke needs to be greased.

 

[Brewcity]

Slip yoke needs to be greased.

So... this is the infamous slip yoke symptom? I am very new to this truck...only had it 4 days.
It feels like the truck is being held back for a split second, then its fine.
But in that second is when the clunk happens.
I read about replacing the yoke with an aluminum one or something along those lines, and its supposed to fix the issue.
Any possibility it could be the rear drum brakes not releasing? That is exactly what it feels like.
Thanks for the help.

---------- Post added at 03:36 PM ---------- Previous post was at 03:34 PM ----------

check the ujoints?

How do you check them, and what am I looking for?
Thanks for the help!

---------- Post added at 05:21 PM ---------- Previous post was at 03:36 PM ----------

Hey guys...I drove home without the radio on, and the windows up....i now hear a whining sound from the rear when accellerating from a stop. It kicks in at about 1000 RPM and around 25-30 MPH, and goes away when I lift my foot off the pedal and coast.
If I press the pedal...its comes back.
Is this related?

 

[HotCarl]

Clunk sound could be U joints. When mine were bad I heard the clang/clunk when I shifted from R to D or vice versa.

 

[Brewcity]

Clunk sound could be U joints. When mine were bad I heard the clang/clunk when I shifted from R to D or vice versa.

Thanks for the help...I don't hear anything when shifting from P to R or D...it now just whines (from the rear) when I hit about 1000 RPM's and about 25-30 MPH, not under. Once I let off the gas..the sound stops...but if I give her gas for even just a second...it comes back.

 

[Tricky]

I had that thunk sound for at least 3 years now and can not identify sound. I did rear brakes, springs, shocks, trans redone, rear end and u joints all done and no one knows where the thunk sound comes from, from the suspension guys to the transmission guy. After work on truck as always it goes away for a while then week or two later it's back. And both shops says they get the same complaints from the obs trucks. After owning truck for 12 years now I just adopted the thunk now, heck I get worried when I don't hear it, lol. And I also only hear it after a stop, at light or stop sign.


Sent from my iPhone 4s using Tapatalk.

 

[BattelWagun]

That house is the slip yoke, unless its thoroughly greased with a really tough marine type of grease every so often, it will clunk no matter what you do. GM did make a nickel plated unit to remedy the problem, costs around $500 though I think.

As for the whining, it could be a number of things. The most common are front hubs (on 4wd trucks), u-joints (very common), and the pinion bearing in the rear axle (the only remedy is a costly rebuild...).

 

[Brewcity]

That house is the slip yoke, unless its thoroughly greased with a really tough marine type of grease every so often, it will clunk no matter what you do. GM did make a nickel plated unit to remedy the problem, costs around $500 though I think.

As for the whining, it could be a number of things. The most common are front hubs (on 4wd trucks), u-joints (very common), and the pinion bearing in the rear axle (the only remedy is a costly rebuild...).

Uh oh...well I just pray its not the last one!
I will change my rear differential fluid tonight, and report back.
Thanks for the help!

 

[bowtiefreak]

sounds like U joints to me. One day mine went from quiet to crunchy with a squeal. This is what they looked like that night: