Thread: Army rebuilt LT95 noisy in 4th only??

There are plenty of threads about LT95 gearbox oils on here with plenty of opinions about alternatives. IME Castrol Syntrans 75W 85 was the answer but others will have other opinions.

Obviously this doesn't address the oil migration issue and I will read further replies with interest.

My LT95 doesnt like VMX80 I find that the original 20/50 to be perfect.
Would doubt if that will fix it but this is my experience with these boxes.

They whine even more in fourth gear low range

Chances are you'll get used to it, or go back to engine oil.

Mark, check your TGM120 for a reference to work done quoting EMEI 189-1. This included the drilling of a return hole between the Transfer and box and the use of engine oil.

You can do the old Toyota fix, by adding a pipe between the transfer filler and the Gearbox filler, by drilling and tapping the plugs.
I still have one lying around somewhere.
I soldered and drilled a 0.2 MM or maybe smaller hole in the gearbox nipple to ensure that a flood to the transfer did not occur on steep hills. You would only need the smallest possible hole like 0.1 or 0.2 MM. In those days I had a set of jet drills.
Regards Philip A
BTW although I haven't tried the gear oils like syntrans, I distinctly remember that 20/50 engine oil was Juuust right. I once tried Penrite 20 /60 and I couldn't change gear when the box was hot!LOL. This was more than 20 years ago.

I've had the return pipe fitted to my LT95.
I thought the oil migrated to the gearbox? I could be wrong. It was a long time ago when I had the problem.

Noisy gears! I'd be asking "What's wrong with 1st, 2nd & 3rd?"

FWIW, my understanding is that the oil migration is due to the input gear spacer in the transfer turning on the shaft. The gearbox-transfer seal is on the outside of that spacer so even if the seal is good the oil will migrate due to the movement between spacer and shaft "pumping" it through.
I was advised when I rebuilt mine to take steps to stop it turning relative to the shaft. I put a small dab of weld on the inside of the spacer, which then locates into the shaft spline so that the two have to turn together.

I'm trying to think what would cause a noise in 4th gear but not in others.
If you drive at the same road speed (something around 70kmh) is the noise definitely only in 4th?

4th is a straight through gear, so no load on other gears in the main box ie not like you're engaging another gear with worn teeth etc
Layshaft is turned directly by the input shaft so its not doing anything different than in other gears either.

I don't recall what happens where the rear gear on the layshaft gets back to the mainshaft as to whether there is anything there that only happens in 4th.
Hence my question about it possibly being related to higher road speeds rather than 4th gear itself - in which case it could still be transfer box.

Steve

As Steve says I would be looking in the transfer for the whine. Unless it is bad I wouldn't worry about it. If it has had a recent rebuild it is possible a new gear is still wearing in to an old one and causing the whine. Oil transfer can be fixed by using mild loctite under the spacer and transfer input gear and on the reverse gear shaft where it goes through the transfer box casing.