VS V6 Tailshaft Coupling Noise

[Grimes]

Gotta noise driving me up the wall.

A couple of weeks ago I spotted that the tailshaft centre bearing rubber was torn and the bearing sitting low in the carrier. Everything was running fine and quiet otherwise.

Ripped out the tailshaft and replaced the bearing and CV joint. CV only because it was 500,000 old and the opportunity was there. Uni joint is fine.

Put it back in with the centre bearing support frame correctly oriented and everything is fine except there’s a rubbing noise like a dud idler pulley when it’s in forward motion. No noise at idle, makes no difference if the clutch is in or out, no difference what gear it’s in. Quietens down at highway speed. No high temps on any bearings or the CV joint, no points rubbing anywhere either.

Just in case I had a weird coincidence going on I ripped the rear wheels and drums off and checked for a hung up park brake shoe but they’re all good and the axle end floats are OK too.

Any thoughts? Has anyone experienced the rubber coupling connecting the tailshaft to the getrag box going out? Could that be the issue?

Cheers.

 

[Immortality]

Not just a bad bearing in the new centre support maybe?

 

[Grimes]

I don't think so. It’s not continuous, but frequent. I had the carrier frame undone tonight checking fit-up /orientation and spun the bearing and it’s smooth as silk. Not getting hot either on long runs.

 

[Grimes]

One more bit of info I left out and why I asked about the coupling. Tonight I reversed the carrier frame orientation for a quick experiment and drove it to the end of the street and back. The noise got worse.

 

[Immortality]

Changing the hanger bearing orientation would put more load on the gearbox output shaft bush. Maybe in the process of R&Ring the drive shaft it's damaged the bush or bearing? (can't remember what the end of the getrag box looks like).

 

[Grimes]

The back of the getrag has a three spoked yoke the rubber coupling bolts to. The shank of the yoke has the speedo inductor gear on it. The removal of the driveshaft can’t hurt the box bearings but I also wondered if running with a collapsed centre bearing rubber might’ve worn something there that alignment is now revealing.

 

[Grimes]

Finally got to the bottom of this. Jacked the rear end on stands, took the wheels off and ‘drove it’ to pin point the source. It was coming from the centre bearing and is most likely a steel slinger rubbing against the fixed rubber shroud when the shaft is dropped down a bit at low speeds. Gave the slinger (but not the bearing) a squirt with WD and the noise disappeared. If it comes back and doesn’t rub itself out I’ll drop it out and sort it out properly.