Thread: Oil Recommendation for LT95 4 speed box and Isuzu 4bd1

Wow, so I didn't think choosing an oil for the gearbox would be so difficult.

I've just finished repairing 2nd gear and a few bearings in the box and now just need some oil to go in it. From what I've gathered before I got the car and dismantled it for a rebuild. Dad used OMD115.

Now from what I've found, the following oils can be used:

20w50
15w40
VMX80
Castrol Syntrans and Syntrax

Now I relise this is a fairly old thread but was very helpful to a point.

Just need a bit more help narrowing the oils down. I'm thinking of the Castrol VMX80, Syntrans, or Syntrax.

Any advice would be great.

Sean.

i was once told by a bit of a land rover guru, that putting too thick an oil in the LT95 causes the internal oil pump drive (plastic square drive) to strip and fail.
best stick with the manufacturers spec on the oil type, which according to my manual is BP VISCO 200015W/40 OR VISCO NOVA 10W/40, CASTROL GTX 15W/50, DUCKHAMS 15W/40 OR HYPERGRADE MOTOR OIL, ESSO SUPERLUBE 15W/40, MOBIL SUPER 10W/40, and a few more that just don't exist anymore.

Stick with 15W40 engine oil and you won't go wrong. I can recommend this after 550K running (box and TRB transfer). behind a Turbo motor with zero problems.

I found VMX80 improved the gear change but was too thin for our hot environment.
I went back to 20w 50 and its a different gearbox.

Thanks for the advice. I'll give the 15w40 a try and see how it goes. Also I read about Morey's additive, do many people use this and is it worth it?

Originally Posted by HotWired

Thanks for the advice. I'll give the 15w40 a try and see how it goes. Also I read about Morey's additive, do many people use this and is it worth it?

Nooooooooo ! It's bloody snake oil.

If a 15W-40 engine oil isn't good enough, (and I think there are better alternatives available) use a 75W-90 manual transmission fluid like Castrol Syntrax, Motul Gear 300, etc.

anything other than engine oil eats the little brass shims i was told by a gearbox rebuilder. didnt know enough to argue so thats what i used in mine...

Originally Posted by incisor

anything other than engine oil eats the little brass shims i was told by a gearbox rebuilder. didnt know enough to argue so thats what i used in mine...

A GL4 or buffered GL4/GL5 spec fluid won't

I just wouldn't go too far on engine oil, at a guess 10,000km tops.
Engine oils generally don't cope very well with the shearing inherent in a manual gearbox.