Everytime I hit or let off the pedal I feel a clunk in the rear. I Raised the back end off the ground and turn the wheels back and forth and It looks like possible play in the hub/axle splines. Clunks when going from park to any gear. It's not transmission or rearend as I've checked those. I replaced both axles and torqued the center bolts with spacer & washer to spec. Been driving it this way for awhile thinking it was play in the rear end. Now I might need another two new axles and hubs... Any idea what can cause this?

Year, model, auto, manual, miles, locking glove box😎???

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Sounds like it may be the cv joints. Park the car in a manner that is safe and put it in neutral. Then see if there is any up and down play in the half shaft. It should be tight up and down but some slide in and out is normal.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sorry. 1985 300d w123

Both CV axles are new. There's no play in the axles but some rotational play at the hubs

You may also want to closely inspect the rear sway bar links.
Their mini ball joints do fail and can create quite a racket.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Have an assistant put it in D with their foot firmly on the brake and power brake it slightly to see if anything shifts, repeat same in R. Stay clear of the car just look for wheels moving excessively or listen to locate the sound.

I'm guessing driveshaft support, flex discs or subframe mounts.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

You said new Axles; are we speaking of new Asian made Axles or rebuilt Mercedes axles? Or?

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84 300D, 82 Volvo 244Gl Diesel

Asian made. Bought em from advance auto. They were like 60-90$ each

The Washer that goes inside of the middle of the hub is supposed to be one use only and provide tension to pull the axle into the hub when torqued properly.

The rear hubs are only supposed to have end play of 0.04-0.06 mm. That is not much. To pull a wheel hub out a lot of work and you need a special tool.

Repair Links Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

They spoke of the Plastic links on the Rear Sway/Torsion Bar but there is also Rubber Bushings where the bar pivots.

Look at the large Differential Support Mount at the rear of the Differential and the Sub Frame Mounts.
I don't know how in particular to inspect the Trailing Bar rubber Bushings but when I found my Sub Frame Bushings shot the Trailing Arm Bushings also were. Perhaps in the repair links you can find what to look for.

When my Subframe and Trailing Arm Bushings were shot when I turned there was sort of an unsteady feeling. Can't recall if there was any thumping or not.

Maybe the Rubber on the Shock Rubber on the Shock Absorbers has rotted out or compressed allowing the shocks to bump up and down

You also might sit in the Back Seat and have someone else drive so you are closer to the noise.

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84 300D, 82 Volvo 244Gl Diesel

Check the Exhaust system for play.

Also I had a mysterious thumping sound go away after I took all of the stuff out of my Trunk. I turned out it must have been something in the trunk tamping around.
I had the same thing happen with a tinking sound. It turned out to be some wrenches piled on top of each other that were making the noise when the Car was moving.

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84 300D, 82 Volvo 244Gl Diesel