Author Topic: Clunk out of rear end when shifting  (Read 579 times)

Jbarela

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Clunk out of rear end when shifting
« on: May 07, 2022, 08:45:50 PM »
Hey there, the 66 is starting to clunk when I am slow on the clutch, slow dump kind of. Crawled under the car, the diff is leaking and I can turn the drive line back and forth with about 1/4 inch of play when in neutral..is that normal?

Drew Pojedinec

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Re: Clunk out of rear end when shifting
« Reply #1 on: May 08, 2022, 07:14:39 AM »
Not normal.
I would expect too much backlash between pinion and ring gears.
Could be due to crush spacer or loose pinion nut too.

shelbydoug

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Re: Clunk out of rear end when shifting
« Reply #2 on: May 08, 2022, 10:15:48 AM »
The amount of play you mention is about right on a 3.89. Since you mentioned a leak, this could be as simple as the rear is out of gear lube.

Depending on what is leaking, you probably are going to have to pull it out.

There is a pinion seal and the gasket to the banjo housing is just a paper gasket.

While it is out, you can check for play in the bearings and check all the bolts for tightness. It will also let you look at the wear pattern on the ring and pinion which will indicate if the issue is wear on the ring and pinion where they engage.

If you have been running without lube or very low lube, any of these scenarios are possible.

While it is out, check the play in the axle bearings as well and make sure that the backing plate gasket and the axle seals are good. It wouldn't be a bad idea to replace those while it is apart either.

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Jbarela

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Re: Clunk out of rear end when shifting
« Reply #3 on: May 08, 2022, 11:48:29 AM »
The terrible thing is that there is less than a 100 miles on the rebuilt pumkin. The entire rear was restored kf course so new everything. I went with an LSD unit instead of a Detroit locker. I appreciate the feedback as I am not knowledgeable in the area. I figured it should all be a direct drive gearing so there would be no play. Definetly it never clunked in the past so going to let the shop figure it out.

shelbydoug

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Re: Clunk out of rear end when shifting
« Reply #4 on: May 08, 2022, 03:01:04 PM »
The terrible thing is that there is less than a 100 miles on the rebuilt pumkin. The entire rear was restored kf course so new everything. I went with an LSD unit instead of a Detroit locker. I appreciate the feedback as I am not knowledgeable in the area. I figured it should all be a direct drive gearing so there would be no play. Definetly it never clunked in the past so going to let the shop figure it out.

"Best laid plans of mice and men".  ;)
68 GT350 Lives Matter!