Trans Sudden Clunking in reverse

[Bertdavis2000]

Ok maybe a dumb question. I have a 76 CJ. Replaced my rear drive shaft, both yokes, and unjoints a couple months ago. Have had zero issues. Drove it yesterday and it drove great. Shifted perfectly all gears forward and reverse. Today I go to drive it and when I shift in reverse it’s good until I start to accelerate and release the clutch. It shakes and clunks what feels and sounds like front drive shaft/Transmission /tease area.

The only thing that I did between yesterday and today was worked on my alternator. Currently my battery cables are loose on the battery for easy removal while I keep working on the alternator. Could a loose battery connection cause the clunking when I go into reverse? I’m hesitant to try it too many times before I have a good idea what’s causing it so I don’t cause bigger damage. Thought I’d rule out the dumb mistakes first.

 

[CJ]

I don't see any correlation but crazy happens... Can you put your Transmission , tcase, diffs in your vehicle details (especially since you have an engine swap) so we know what you have? LINK -->> Account Details <<--

In the mean time... Transmission , TCase, front and rear diff?
Are your hubs unlocked and in two wheel drive? If so then there should be no power to the front.

 

[KRUPP]

Probably nothing to do with the battery/alternator work you did.
My first hunch is the Torque Arm bracket from Transmission to belly pan. Check the rubber on this arm, on both ends. If it's original it probably needs replaced, along with the motor mounts.

 

[hole]

I second what Krupp said, but in reverse. Open the hood, set the parking brake (or chock rear wheels) and let out the clutch in 1st and reverse and see if the engine moves excessively either way. It might be easier to have someone helping watch the engine for you.

 

[Project86]

Check your U joints.