40 replies to this topic

[MFM]

mfm  hi in all the cars u have owned with whiney diffs,  gtr, Ltd  etc  have u ever replaced axle bearings, lol 

The cars that did have diff whines (GTR/LTD) were eventually fixed by diff replacements so there was no need to replace the wheel bearings. I have owned a car which required rear wheel bearing replacement (HG Brougham) so I am familiar with diagnosing the traits of a worn wheel bearing. Don't forget I took the proprietors of two of the diff repairers for a drive in my car with their reconditioned diff in the car, to seek their opinion on the noise and both said definitely diff, not wheel bearing or gearbox. So when the noise is occurring at a specific speed , as soon as I accelerate it gets a lot louder. If I back off and cruise its softer and when I take my foot off the accelerator there's no noise (Gone). In my experience, wheel bearings present their noise at a constant rate increasing in intensity the faster you go and you can intensify the noise by turning the car sharply from left to right (effectively placing more weight/load on each rear bearing) which will increase the noise. Also when the diff whine is at its highest tone if I push the clutch in- Noise stops!!!. That in my experience is not wheel bearing but as some of you have said, it doesn't hurt to replace them anyway.

Edited by MFM, 03 February 2022 - 06:26 AM.

[LCK186]

MFM hi if u are sure it is diff whine, I would borrow a centre from a friend or member in qld to make sure, otherwise u are throwing money down the drain, another thought I bought an lj gtr moons ago when driving it home a whining noise appeared, after checking diff oil etc

,  etc etc it was the gear box very low on oil, topped it up and noise gone,    mate im trying to help u, if u were in melb I would be happy to lend u a centre to resolve your problem, 

[conway]

Noise stops when pushing in the clutch, interesting, the diff gears are still turning at the same rate but not under load.

[MFM]

I've got one more 3.36 LSD that I can try, I'm just f....over it. 

[ozyozyozy]

Sounds possibly gear or preload issue.
Pushing the clutch in will change the load on the pinion.
Usually if it changes with acceleration and coast its either a tooth contact issue or preload.
You wont know if the pinion preload is ok unless you take the centre out so the pinion free spins.
Always use new collapsable spacers, old ones can be used to help get the shims or adjustments/tooth reading correct then swap it out for new.

[S pack]

Don't forget I took the proprietors of two of the diff repairers for a drive in my car with their reconditioned diff in the car, to seek their opinion on the noise and both said definitely diff, not wheel bearing or gearbox.

Did they offer any potential remedy, like 'leave the car with us so we can pull the diff back out and have another look at it' or was it a case of 'yeah mate the diff is noisy' thanks for your custom, see ya later.

[LXCHEV]

Rather than using crushable spacers, it’s good practice to have a machined one made up - that’s what I’ve had done with all centres I’ve had re-co’d by the pro’s.

[MFM]

Did they offer any potential remedy, like 'leave the car with us so we can pull the diff back out and have another look at it' or was it a case of 'yeah mate the diff is noisy' thanks for your custom, see ya later.

Yeh that was pretty well it Dave. I got the impression from the two reputable repairers here on the Gold Coast that nothing could be done although the 3rd repairer I used (Diff Lapping Brisbane) offered to adjust the settings so I removed it again and sent it to him but still no difference. In fact the diff fully reconditioned by one of the Gold Coast repairers was the one I took to Diff Lapping to get lapped to see if that would fix it, which it didn't. When I say I'm f...cking over it, you can see my fustration. Its not like I haven't thrown money to try and fix the problem. You are in Brisbane so who else would you suggest because I'm happy to send these reconditioned diffs to anyone to have a go at them.

[S pack]

My only recommendation is Diff Lapping.

I just find it hard to believe that you could have three differentials that are different ratios that all make the same noise in the same road speed range.

So you have the rear axles and the crown wheels of all three differentials turning at the same RPM for a given road speed, when driving in a straight line, but the pinions are turning at different RPMs.

I am probably wrong but surely the pitch of the noise and the road speed range in which the noise is evident would be different for each different ratio?

Still think before continuing to beat yourself up over it get the axle bearings replaced so, if at least nothing else, you can definitively eliminate them as a noise source.

[jpxu1]

And since the tailshaft uni's are constants in this puzzle, and not expensive either, I would replace them as well.

 

Of course there is the possibility of eliminating the problem and forever left wondering whether it was the uni's or axle bearings :-)

[MFM]

And since the tailshaft uni's are constants in this puzzle, and not expensive either, I would replace them as well.

 

Of course there is the possibility of eliminating the problem and forever left wondering whether it was the uni's or axle bearings :-)

I had the tailshaft balanced and uni's replaced (all at the same time). They recommended I replace the front yolk (or whatever you call it) so did that. Where I've probably misdirected you guys when I mentioned the speed at which the whine starts and finishes is because my Tacho needs fixing as its showing 1000-1500rpm more than it should at this speed (4500rpm) (3.36ratio) so I didn't want to provide you guys with a engine RPM because its incorrect and is likely to be inconsistent/unreliable source. This is why I'm asking the question on this forum because the diff that was in the car when I bought it (3:55 LSD) was doing the same thing at the same speed/RPM (whatever that is) but it was't reconditioned so I assumed a reco would fix it, so that was the start of this journey. Personally I am convinced its in the gearbox although I can't find anyone to agree with me but its weird that all the diffs are showing the same symptoms at the same RPM/Speed. Could a worn main bearing in a gearbox cause this at a certain RPM under load?

[dron]

Have you checked the pinion angle. If it is out it will make noise.  Had trouble with a wb 1 tonner years ago. As that is leaf springs i just put a wedge plate in  to corect it. Bit harder in a Torana but still worth checking

[grumpy xu1]

The pinion angle should be fine in his standard diff for the car, that doesn't appear to have had any work done to it.

[MFM]

Dave I'm retired now so we can catch up and come for a drive. You'll know exactly what I mean then.

My only recommendation is Diff Lapping.

I just find it hard to believe that you could have three differentials that are different ratios that all make the same noise in the same road speed range.

So you have the rear axles and the crown wheels of all three differentials turning at the same RPM for a given road speed, when driving in a straight line, but the pinions are turning at different RPMs.

I am probably wrong but surely the pitch of the noise and the road speed range in which the noise is evident would be different for each different ratio?

Still think before continuing to beat yourself up over it get the axle bearings replaced so, if at least nothing else, you can definitively eliminate them as a noise source.

[S pack]

Dave I'm retired now so we can catch up and come for a drive. You'll know exactly what I mean then.

So true, so true.
 

[bat 53]

can't hear it so only guessing 

had a borg warner i shorten for a bloke 

came back winging about noise , pinion angle so on 

went for a drive , noise was from the gearbox 

turned out to be speedo drive and cable