8.8 clunk?

[Monty78]

If I am driving at a steady speed and let off the gas I hear a clunk coming from the rear end. I think it's the diff and wondering if this is normal?
Had 3.27 gears installed along with the axle in my '78 wagon. It is a reputable shop but I am wondering if it was set up correctly.

[massacre]

Could it be play in the rear u joint?

[richpet]

An actual clunk would seem to indicate play in a rotating part. Under power the slack is taken up. When you let off the parts separate until they hit metal the other direction.

As massacre said, U-joints are a common source.

Try to manually rotate the drive shaft by hand back and forth. Any play points to a likely source of the clunk - wear in the u-joint(s).

[Monty78]

Thanks for the responses I will check that out.

[85GTGuy]

Could also be excessive backlash in the rear gears.

Or too much play in the driveshaft yoke... but maybe not that if it seems to be coming from the rear of the car.

Definitely, like others have said, U-joints are the first thing that comes to mind,

[1984GTTurboVert]

Since everyone already stated the best and first place to check ill say check the bushings for the control arms and the shocks when you are back there. Especially since you just had the rear installed.

[gr79]

2x check rt lca ft bushing.
Took me years to figure out what was causing a clunk back there.
First suspected loose or wrong bolts in the uppers replaced few years prior with FMS ones.
Eventually the car would yaw back and forth on off throttle.
Quick inspections reviled nothing. Rocking the parked car back and forth grabbing the tire did make the noise.
Did notice the nose of the axle would move up and down. No snubber. Did not contact floorpan.
A real close inspection with a mirror and flashlight revealed a shot bushing.
Rubber was split and damaged causing the bolt and bushing to move fore and aft.
Could not see much on the wheel side. Damage was clear on the side facing the ds.
Figure age and lots of miles no racing or many hole shots stock 2.3T.
Replaced the stock arm with another stock arm from an SVO. Solved.
When a symptom becomes immediate noticeable after a repair is another clue for diagnosis.
Swinging exhaust can make noise too if they contact something. Motor torque action.

[Monty78]

Had new boxed aftermarket upper and lower arms and subframe connectors installed along with the 8.8.
I am suspecting backlash and will probably end up back at the shop.

[flinfantryrebel]

It sounds a lot to me like what I had in my Tacoma which was a broken u joint

[Monty78]

https://youtu.be/jNqxzOsIOps
Not the u-joint.
How do I embed video?

[machinedoc]

Just had a look at the video. Appears that there is a lot of backlash in the rear gears.
Have also seen that an improper torque on the pinion nut.
Have the shop that did the install look at it. Hopefully they will honour their work.
Good Luck