Hi guys, it's been awhile.

My 75 started making a cluncking sound when I let off the gas at free way speeds.

I jacked up the rear of the Vette and checked for movement in the wheels.
The drive shafts all seem to be working well, but there is play in the wheel it's self.
Noticeably, the tire has play moving the top of the tire back and fourth.
One hand on top and the other on the bottom of the tire.

So what all will it take to fix this?
I already have 500 hours in the build so far, what's a few more.

By the way I have 99053 miles on her.

Ralph

maybe check the front diff mount rubber.

If the play is toward the center of the car,(inward and outward) it's the wheel bearings - if the trailing arms don't twist. If the trailing arms twist it's the trailing arm bushings. (assuming the radius rod bushings are good)

The diff mount is also a source of the noise you hear if the bushings are worn.

Worn universals also make a clunk, check by turning each one and looking for play.

When I opened up the 71 - 2 universals were bone dry and the caps were discolored. (a sign of overheating)

Just a few thoughts,,,

I'd follow blues advice above and I would also check the run out of the wheel bearing on the side that has the issue. Typically a bad wheel bearing won't clunk, it'll just make noise period.

Other areas I'd check
Rear snubber cushion,
Front trailing arm shims (missing)
Universal joints.

Willcox.

how old is the fluid in the rear

All of the above. Do the simplest first. Change diff fluid and add two bottles of posi fluid, change diff front bumper, then move out to u-joints, bearings, trailing arm pivot bushings. At 40 years old you probably need all of it. Only 99053 miles?

Less than 5000 miles on fluid.

Actually I replaced the fluid, then the rear housing cracked. About 7000 miles ago. Purchased a heavy duty housing and put Valvoline. LA in it the 2nd time.

Yes it was a barn/garage find. It had set for 10years. The old guy kept thinking some day he would have the money to fix it. 4 years 500 hours and $15000.00 and I'm still working on it.

They are new also. Most everything is new except the actual rear end and the 2 short drive shafts. But there is minimal play.

Don't get discouraged.....you are about par for the course....my project will reach $15,000 when body work is done and the new paint is dried....LOL!

I had clunk when going from park to drive and reverse. original 3 inch axels 1975 with 83k. turns out half shaft u joints were shot and actually beating hell out of the wheel flanges also. 700$ parts and labor , spicer u joints, new wheel flanges, bolts and French locks. Reputable shop with corvette experience. Good luck. I knew it was coming as I had gone thru everything except the halfshafts and connections.

Just a thought,, usually with a posi rear if the clutches are sticking you will feel a slight side to side "slip" when exiting a turn. Sometimes it will also happen when you are just into the turn, it kinda feels like a side shove in the rear.

One thing no one mentioned, check the spare tire carrier and wells - Jack etc for items rolling around.. don't ask..
sometimes it's a simple thing..

I like the one that was In my car better, and it did not rattle, just heater hose and silicone..

they are a work of love...