Drivetrain clunk after rear axle service...

[Mark Francois]

I've got a 2003 Yukon 2wd with the 4.8l engine and after having my rear axle serviced a few months ago I developed a hollow sounding thunk from underneath the truck when shifting from drive to reverse and back. Sometimes it will do it when backing up my driveway and adding throttle but I cant rundown where it is coming from. They did replace the pinion seal during the service so my first thought was the rear u-joint but I looked and there is no slop in them... I am out of thoughts for now so any input you guys might have would be great. as always, thanks in advance. 

Edited October 31, 2022 by Mark Francois

[CamGTP]

Get under the truck while someone does the shifting, pinpoint the noise that way.

 

Obviously be safe about it, choke the wheels if you must. More than likely it's still a u-joint or the splines on the slip yoke are totally worn out causing the clunk you hear.

[Mark Francois]

13 minutes ago, CamGTP said:

Get under the truck while someone does the shifting, pinpoint the noise that way.

 

Obviously be safe about it, choke the wheels if you must. More than likely it's still a u-joint or the splines on the slip yoke are totally worn out causing the clunk you hear.

I don’t believe the splines on the yoke are worn at 140k miles but who knows. I did get down, watch, and listen but the noise is difficult to pin point. Plus my wife was doing the shifting while I was laying next to the running truck and she knows how much insurance I have on myself so yeah I was a little nervous lolol