Datsun Roadster Forum-311s.org

Are you certain that it is from the rear end? It sounds like clutch chatter to me

Oily clutch?

Did you find the fault ? Sounds like a frozen U-joint, would have to remove shaft to test. I would also want to see if the two U-joints are in phase as the shaft can be assembled wrong at the splines.
Good luck.

Update. I finally got it to my buddies shop and got it up on the lift. No problems with mounts, drive shaft or u joints as far as we could see. His guy drove it and got it in gear on the lift. He thinks not a differential issue either. Although he didn't give a good answer either. He didn't think it's clutch chatter either (that was my first guess) but thought it IS coming from the rear end.

ed B wrote:Just for the heck of it, check your motor mounts as well.

+1
Check your motor mounts. Does the shifter move excessively?

jarhead wrote:Update. I finally got it to my buddies shop and got it up on the lift. No problems with mounts, drive shaft or u joints as far as we could see. His guy drove it and got it in gear on the lift. He thinks not a differential issue either. Although he didn't give a good answer either. He didn't think it's clutch chatter either (that was my first guess) but thought it IS coming from the rear end.

Did he verify that the U-joints are in phase as twistin asked?

Motor mounts are good but I'm not sure about the u joint "phase" question. He said "u joints are fine."

Let me clarify the problem once more. Rear end shakes when clutch is engaging. It stops once fully engaged and I go through gears. It is worse when I engage the clutch with higher rpm.

I'm still betting on clutch chatter

You don't have any load on it when the wheels are off the ground. the clutch won't chatter without some resistance. It sounds like the clutch to me also

That's what I was thinking. So it gets back to my concern. Assuming it's clutch chatter, will it harm anything to keep driving it and will it get any better if I drive the hell out of it?

I doubt that it will get better. I had chatter in a mustang, and it almost ruined the flywheel. It is also vet hard on all of the mechanics of the car

spl310 wrote:I doubt that it will get better. I had chatter in a mustang, and it almost ruined the flywheel. It is also vet hard on all of the mechanics of the car

The heat hardens the face in those spots and worsens wear. If it's oil on the clutch, then not as bad on the flywheel, but the chatter and shaking loosens stuff. Either way you probably need a clutch, and if it's a leak, fix the leak while it's apart. Is the engine or trans losing oil or any visible leaks?

Vibration is quite the destructive force. I had a tailshaft bushing fail once while on the road. The vibration resulted in the bell housing breaking.

dbrick wrote:

spl310 wrote:I doubt that it will get better. I had chatter in a mustang, and it almost ruined the flywheel. It is also vet hard on all of the mechanics of the car

The heat hardens the face in those spots and worsens wear. If it's oil on the clutch, then not as bad on the flywheel, but the chatter and shaking loosens stuff. Either way you probably need a clutch, and if it's a leak, fix the leak while it's apart. Is the engine or trans losing oil or any visible leaks?

spl310 wrote:Vibration is quite the destructive force. I had a tailshaft bushing fail once while on the road. The vibration resulted in the bell housing breaking.

It's unanimous! Vibration is evil and likely causing unseen damage to other components. Pull the tranny and inspect the clutch. It could be as simple as a broken spring or rivet and the resultant unbalance causing vibration.

Better to just deal with it. Pulling the engine and trans isn't too hard.