I just replaced the steel driveshaft with an LSx aluminium shaft. Everything slipped in and bolted up fine (tight squeeze though).

But while underneath the car, transmission in neutral, i hear a click every half revolution of the driveshaft. I cant feel where its coming from but it sure sounds like its in the slip yoke area.
The click is also at a certain spot and not just random. For example, turn the shaft from 12 o’clock to 6 o’clock, click. Turn back to 3 o’clock, then to 6, click. Turn to 9 o'clock, then back to 6, click.

The rear Ujoint was replaced. The front is original but feels fine. There is no play in the shaft either.
(92 Z28, automatic, G80, 80k miles)

 

Update: I put the steel DS back on, and I get the same symptoms.
So this is either complete coincidence that another issue pops up while i happen to be swapping out drive shafts. Or maybe this noise is normal until the rear tail housing fills back up with fluid? dunno
Hopefully 20ft/lbs toque is good enough for the yoke straps.

 

Torque spec for the strap bolts is 12-20 ft.-lb.

I just tighten them until they strip and then back off a 1/4 turn.

 

whats the weight difference between the shafts?

 

The aluminium is probably between 33-50 percent lighter.

 

I recall someone mentioning a cable/cable shield of some form under these cars that can slap on the tailshaft? anyone else recall this?

 

If it's making the noise every half rotation I'd say one of the joints is hitting something.

From memory, the Cat Converter heat shield is close to the drive shaft, but clear of the joint.

Maybe the hand brake cable?

 

When ever I have the suspension hanging the driveshaft lightly bangs against the exhaust, but once the car is on the ground again there isn't any contact.

 

Thanks for replies. I checked again, felt around everywhere, and cant find anywhere around the DS that is tapping on anything. It seems like it may be inside the tailshaft or up further towards the front.

 

do you have rear drums on this thing? i had a funny click at one point that was a brake shoe stuck on and would click at every revolution. if youve got a drums, give them a few wacks with a sledge hammer, see if it releases.

 

Bad front universal joint?

Not expensive to replace both joints anyway.

 

It sounds like the governor weights in the rear area of the trans clicking. Which is normal.

 

yea, possibly inside the tailshaft is where your problem is. not hard at all to disassemble and investigate. might loose a little trans fluid but thats about it. might be a good time to replace the tailshaft o ring, rear seal and the bushing as well.

 

No they are discs. And the sound is defintely coming from up around the trans area.