R33 Tail Rumble

[Bloodnut]

Hey all,

Just a quick query for those who know more about cars than I do:

My car (1997 R33 Gts25t S2 - 78000k's) has started to make a rumbling sound - no noticeable wheel vibration (just the rear view mirror wobbles) whenever I take my foot off the accelerator at speeds of 110kph or more.

I have been told by a friend who is a mechanical fitter (not a mechanic but mechanically minded) that this could be a wornout uni joint on the tail shaft, and is something to do with it moving when not under acceleration. Something like that. I am not mechanically minded (at least not with gearboxes and drivetrains) and just want to know if this is something to worry about or to get replaced soon, and how much I'm looking at paying?

Any input would be greatly appreciated.

Cheers, Jon.

[wlspn]

Is it only rumbling or sort of rattly as well?

If the noise is just rumbling & only there when coasting (backing off & rolling) there's a good chance it could be the large pinion bearing in the diff.

It shouldn't cause too many problems besides maybe metal going through the other bearings & damaging them.

But hey, if you were going to get a diff rebuild you would replace all bearings anyway so not a major issue.

Hunt around for some prices. Call in to diff/trans specialists & someone will probably be happy to take it for a test-drive, give you their first-hand opinion & a rough starting price. Depending what needs to be done when it's opened up I would expect it to cost $400+ or around there somewhere...

Probably don't really need to rush. Have had cars come in where you can hardly hear the radio over the diff noise & sometimes still only need just bearings & a set-up.

[lowbro]

Hey Jon,

Welcome to my world, I have had the exact same issue for sometime now and it is getting so uncomfortable to go over 110+

Does yours really start to rumble/vibrate when on the gas at 100+ and then when you back off the gas it feels heaps worse?

I reckon wlspn is onto something here, I had my 1 piece tail-shaft balanced not so long ago, hardly made a difference, I had a new LSD diff centre put in 2 wks ago, problem is still there, giving me the shits I tell ya, and has so far cost me some serious dollars. Would luv this one resolved, then I am happy to continue with other project mods.

[lowbro]

Jon,

I should also mention that the worn out uni your friend has mentioned would be a lot of people's first diagnosis for this type problem.

My 1 piece tail-shaft does not have a centre and both uni ends were recorded when balanced recently as being really good, so I reckon we can eliminate the tail-shaft altogether and move towards it being the diff for this one.

This is definitely not a problem I can live with while I own my car, if yours gets as bad as mine you will start to hate driving at that speed.

[Bloodnut]

Thanks wlspn,

Will look into phoning the guys you mentioned and getting them to check it out. It doesn't rattle at all, just a rumble, and its nothing severe, just that I cant use my rear view mirror over 100-110.

Lowbro, yours sounds quiet a bit worse than mine, but I would rather fix mine soonish just in case it is something that can do damage elsewhere or as you said, become a big pain in the arse!

I'm not in Perth again until August, but I will see what they say about if it is a diff thing (sounds likely) or a uni-joint thing. I'll still get them to check the condition.

[lowbro]

Thanks wlspn,

Will look into phoning the guys you mentioned and getting them to check it out. It doesn't rattle at all, just a rumble, and its nothing severe, just that I cant use my rear view mirror over 100-110.

Lowbro, yours sounds quiet a bit worse than mine, but I would rather fix mine soonish just in case it is something that can do damage elsewhere or as you said, become a big pain in the arse!

I'm not in Perth again until August, but I will see what they say about if it is a diff thing (sounds likely) or a uni-joint thing. I'll still get them to check the condition.

My car is off to a diff specialist this afternoon for diagnosis, and I will let you know what they say for my problems.

Locating an 34 sedan manual tailshaft has become an impossible task to change over from a 1 piece to a 2 piece again to eliminate or resolve my rumble/vibrations problems at 90km+

[Guilt-Toy]

make sure the exhaust is not vibrating or rubbing on anything. sounds funny but i was chasing issues for ages and it ended up being the exhaust moving about and touching the rear bumper