I have an '89 cable LS trans with the small clutch spline. Picked it up from a junkyard with a claimed 115K on it and have put another 6-7K on it since. I'll assume it's all stock and never been rebuilt. I put 400whp through it almost daily during the summer months.

Problem recently is I get a rhythmic noise, most noticeable when decelerating in gear at speeds below 40mph. The noise sounds like, if you have the front of the car off the ground and you roll one of the wheels back and forth, you can hear the gears and differential engaging in either direction from the slack in the drive train. It produces a slight "clunk" sound. This noise happens very rapidly and decreases with vehicle speed. It goes away if I disengage the clutch.

The transmission seems okay otherwise. It has only slight input shaft bearing noise when idling in neutral, but it's been there since I got it. I can hear the noise described above somewhat if maintaining a slow speed in gear, especially up a slight hill. The car bounces a little almost like there is slack in the drivetrain, or could be the sprung clutch? It is an Action Clutch 2MS and flywheel btw.

 

Lightweight flywheel?

 

Chromoly 10lb flywheel

 

When I went to a light flywheel I picked up a lot of gear chatter noise on decel. Put the clutch in and the chatter goes away.

 

Maybe. I've had the clutch and flywheel setup for almost 2 years now though, and the noise just started. It seems to be getting worse, and not only can I hear it but I can feel it too. Like there is some kind of resistance somewhere pulsating the entire drive train. Again, push in the clutch pedal and it goes away. I am noticing it during light acceleration now, too.

I think I may park the car until I get it figured out. I had something similar with my last transmission, except it was more of a hard CLACK sound during decel, not this kind of gear or bearing rumble noise. Anyway, my differential blew apart shortly after on the last one.

Not sure if it could have anything to do with the DSS axles I installed recently either.

I run Torco RTF fluid.

Guess I'll jack up the car and try spinning the wheels to see if I can feel anything.

 

Hate to say it, but it sounds like a broken or chipped tooth to me.

 

Me too. Anyway to tell whether its on one of the gears or in the diff? It’s worse in 3rd and 4th but noticeable in 2nd and 5th as well. Seems sensible it could be the diff. Maybe time to upgrade.

 

That would make me think it's the ring gear / pinion.

 

Agreed. Thanks for your consensus.

When I find time, probably over the winter I will pull the tranny and crack it open to see what happened. Never opened one up before. Just don't have a lot of time now with a newborn in the house.

 

Not sure if this amount of play in the diff is normal. The other wheel is not moving when I do this. Also this one spot seems to have more play than anywhere else through the rotation.