Thread: For crying out loud... 5th gear whine

I had a similar noise in mine but at about 70km/hr upwards. I just changed the gearbox oil and the transfer case oil. The oil in my transfer case was pretty low, has that been changed/topped up recently??

I'm not an expert with this, but it solved my noise problem.

Box boxes were filled when I put them in the car - penrite transgear 75w80 mtf94 for the gearbox and sae 80-90 for the transfer. It's only in 5th under load. I'll crack the gearbox tonight and check the level - perhaps as it was empty of oil for a short while there was an air pocket or unprimed gallery or some such resulting in low oil... I believe I noted it taking a few hundred ml less than what the manual quotes...thanks for the idea

Do a search on this forum for R380 5th gear bearing failure. Don't drive it to destruction you can change the rear bearings without pulling the main transmission out. You will however need to pull the rear housing off after removing the transfer case.

Originally Posted by djam1

Do a search on this forum for R380 5th gear bearing failure. Don't drive it to destruction you can change the rear bearings without pulling the main transmission out. You will however need to pull the rear housing off after removing the transfer case.

Yes I have read it can be done, but it would be a fair bit of a ***** of a job, even with the correct tools!

First thing youd want to do is pressure wash the beejesus out of that area before removing anything, then pull the tcase and wash some more. Id find it near impossible to keep crap from that area out of the box once you have the rear housing off.

You will need some good pullers to remove the mainshaft collar and bearing tracks from 5th gear. There is a chance the cage for the mainshaft rear bearing will get damaged when removing the rear housing, so my have to plan on replacing that one also.

I found the job not to be too bad what I would be concerned about would be the shrapnel that has been created by the disintegrating rear lower bearing. I would replace the oil pump as well. Dave Ashcroft will have the best advice.

Well I've had a couple of days to calm my farm and test a few things. It's a bit different to what I had thought it to be the other night.

The whine appears at around 60kmph and appears linked to vehicle speed. The faster the vehicle goes the louder and higher pitch the whine. The whine is the same pitch at 100kmph in 4th as it is at 100kmph in 5th.

The PO had the units checked & vehicle serviced just before breaking with no such problem reported/found.

The boxes are filled with Penrite Trans Gear 75w80 MTF94 in the g/b and EPX80W90 in the transfer.

I have checked all wheel bearings for play/rumbling or any signs of problems. I have checked all UJ's, all have been recently replaced and have no signs of play. Checked the pinions as well - no play...

I have removed front and rear props in turn and driven in diff lock and the whine is still present.

The vehicle had the flywheel, RMS, spigot bush, clutch kit, fork, slave, throw out bearing replaced when the gearbox was done. New gearbox mounts fitted.

The rear diff was measured and removed to install a locker but after tearing down the center the locker was found to be DOA and the diff was rebuilt and refitted. The measurements were the same (backlash and pattern) when it was installed. The diff leaked badly thanks to a blocked breather and a bad gasket so it drove 10km or so on only a liter or so of oil.

So that's what I have so far...

I am thinking trying a different oil, perhaps even some Nulon G60? Failing this perhaps taking the plate of the transfer and inspecting end float.

Any ideas anyone?

A positive is, you have the rear diff setup ok.
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Okay well I have tried a few more things.

I have added Nulon G60 to the transfer, taken it for a highway drive and no different.

I Have also dropped the gearbox oil and replaced it with VMX-M with G60 added - shifting is now slick as a buttered crumpet - but the whine is still frustratingly present!

I have a video uploading of the sound so perhaps that will help with diagnosis!