Engine oil for gearbox???

[sudso]

Well it's time to drain ALL the oils in my Rodeo and while checking in the manual what oils to get I see that for the gearbox (MUA5C 5spd.) they recommend engine oil, SAE 5W-30 or 75W/85 gear oil.

I've never heard of using engine oil in the gearbox before, surely it would be too thin or am I just old school?

I thought gear oil would would be kinder on the gearbox and help it last longer.

What is best to use?

[bogged]

What is best to use?

what the book says usuallly

[Zeyphly]

we get quiet a few different bits of equiptment through our workshop that uses engine oil all through different parts of them.

[RockyF75]

SAE 5W-30 or 75W/85 gear oil.

Whats the problem, theres an OR in there. If its new and under some sort of longish warranty, i'd ring em and double check, then chuck in the reccomended engine oil just to see what happens I too cant imagine it being thick enough but I've seen crazier things done.

[sudso]

What is best to use?

what the book says usuallly

The book doesn't say what's best, just a choice of the 3 oils.
Quote RockyF70:

Whats the problem, theres an OR in there. If its new and under some sort of longish warranty, i'd ring em and double check, then chuck in the reccomended engine oil just to see what happens I too cant imagine it being thick enough but I've seen crazier things done.

The book actually recommends ANY of the 3 oils. It's waaaaay out of warranty but in retrospect I'm thinking the good old gear oil will do considering the temperatures it gets to around here.

[rockcrawler31]

for an older vehicle i'd prolly go the thicker gear oil, coz by my reasoning it would stick to the gears better and travel through the box into bearings etc.

However,,

In the Army we used OMD 115 (oil, mineral, detergent) in the engine AND gearboxes of the rovers and mogs, and OEP (Oil, extreme pressure) in the diffs and drop boxes (goddamn back to front army nomentclature )

MILO

[Vulcanised]

use engine oil...... if you want to use a thicker oil go up to 60 weight oil. don't put gear oil in it..... the clags up the syncros and it's a biatch to change gears. A mate did this to his car some years ago.... and he had to drain it and put engine oil in. I put engine oil in my Deo and it was fine..... i thought i would be a smart arse and put gear oil in the transfer caser, also a bad move, it meant i had to slow right down to shift between ranges... whereas before i could shift on the fly. The engine oil doesn't break down in the gear box

[Ruffy]

I'm with RoeDao on this one. Tried the gear oil thing and in victoria at least the gear oil is too thick in the colder weather especially and gives notchy shifts. Had plenty come through with engine oil in them with big K's on the clock too.

[dani4JB1T]

I use 15W40 in my MUA, and works good, that`s what say the book. When you fill with thick gear oil (ex: 80W90) the gearbox shifts hard.
For diffs I use 80W90 + LSD lube `cause I have one inside the rear axle. The front diff only gear oil.

I wonder if somebody have tried other oils like Mobilgear 600 series in diffs. ??

greetings mate.

[sudso]

use engine oil...... if you want to use a thicker oil go up to 60 weight oil. don't put gear oil in it..... the clags up the syncros and it's a biatch to change gears. A mate did this to his car some years ago.... and he had to drain it and put engine oil in. I put engine oil in my Deo and it was fine..... i thought i would be a smart arse and put gear oil in the transfer caser, also a bad move, it meant i had to slow right down to shift between ranges... whereas before i could shift on the fly. The engine oil doesn't break down in the gear box

You shift between hi and lo on the fly? I've heard of it being done if you get the revs right but I haven't been game to try it. Maybe I misunderstood you and you meant between 2H and 4H?

Guess I'll find out what oils in the box and transfer when I drain them tonight after work. It all shifts pretty easy so maybe they already do have engine oil in them.

Thanks for all the tips everyone
sudso

[saigo]

Taken from Jackeroo World site. http://jackworld.alphalink.com.au/drivetrain_tips.htm

'Many owners have complained to us that they are suffering from "crunching" gears especially when the engine is cold. We have had some success with this problem by using a thinner oil in the gearbox. Normally these gearboxes and transfer cases should be lubricated with engine oil (as for all Jackaroos) not S.A.E. 90 gear oil. However on the later models we have had some success with using synthetic oils which are thinner than engine oil when cold but less susceptible to temperature-induced viscosity reduction which could cause oil-film failure . We use Castrol Formula "R" Synthetic 10W -60W. '

I have gear oil in mine and it's a cruncher sometimes need to double clutch.
I found the drain holes for the tranfer case and gearbox. But where do I fill the gearbox from.

[sudso]

Thanks saigo, each reply is getting more and more informative and valuable.
Good point about the engine oil losing viscocity too.
I had wondered how standard engine oil would cope at high temps under high pressure.

This Castrol stuff sounds the go, we have a Castrol dealer here in town.
Before that I was thinking a heavy grade Penrite engine oil would do but the synthetic stuff would be around the same price as Penrite.

If your gearbox is a 5 speed MUA5C like mine the filler plug for the t/case is on the drivers side near the torsion bar.
The g/box filler plug is also on the drivers side about mid way up the side of the gearbox.
You just fill it up to the specs in the owners manual:
2.95 lts. for the box,
1.45 lts. for the t/case
Usually the filler holes are the right levels.

cheers
sudso

[sudso]

I use 15W40 in my MUA, and works good, that`s what say the book. When you fill with thick gear oil (ex: 80W90) the gearbox shifts hard.
For diffs I use 80W90 + LSD lube `cause I have one inside the rear axle. The front diff only gear oil.

I wonder if somebody have tried other oils like Mobilgear 600 series in diffs. ??

greetings mate.

Gday Dani, you been a bit quiet lately
You can also use Castrol LSX 90 already formulated for slippery diffs.

Cheers

[dani4JB1T]

Gday Dani, you been a bit quiet lately
You can also use Castrol LSX 90 already formulated for slippery diffs.

Cheers

Gidday Dave...Im just back home 2 days ago. I wrote you a PM on OZ 4wd forum yesterday.

cheerios

[sudso]

Gday Dani, you been a bit quiet lately
You can also use Castrol LSX 90 already formulated for slippery diffs.

Cheers

Gidday Dave...Im just back home 2 days ago. I wrote you a PM on OZ 4wd forum yesterday.

cheerios

Didn't get it.
How did your studies go? In Canada wasn't it?

[Vulcanised]

use engine oil...... if you want to use a thicker oil go up to 60 weight oil. don't put gear oil in it..... the clags up the syncros and it's a biatch to change gears. A mate did this to his car some years ago.... and he had to drain it and put engine oil in. I put engine oil in my Deo and it was fine..... i thought i would be a smart arse and put gear oil in the transfer caser, also a bad move, it meant i had to slow right down to shift between ranges... whereas before i could shift on the fly. The engine oil doesn't break down in the gear box

You shift between hi and lo on the fly? I've heard of it being done if you get the revs right but I haven't been game to try it. Maybe I misunderstood you and you meant between 2H and 4H?

Guess I'll find out what oils in the box and transfer when I drain them tonight after work. It all shifts pretty easy so maybe they already do have engine oil in them.

Thanks for all the tips everyone
sudso

In the Rodeo i could very easily change on the fly between 2H and 4H and 4L........ the only time i had to slow down to do it was when i drained the transfer and put gear oil in it instead of engine oil.

[sudso]

In the Rodeo i could very easily change on the fly between 2H and 4H

Howd you do it without it crunching. I tried on mine one day and and it grinded. Hav to get the revs right or what? In gear or out? clutch in or out?

[sudso]

Oh yeah I put gearbox oil in the t/case, thats what drained out so that's what I replaced it with. Says on the the filler cap to use engine oil as well.
Haven't changed the g/box or front diff oil yet.
The Holden Dealer mechanic recommended I didn't put engine oil in the gearbox but use Castrol syntrax 75W/85 a good all rounder for the climate here.