Thread: Isuzu gearbox oil

Seeing as though there is a recent thread in relation to lt85 gearbox oil maybe one on the Isuzu boxes may be of benefit due to the increasing popularity of this conversion...

For the few that do not know I have an MXA-6R (6speed) gearbox and the nameplate suggests 5w-30 grade oil to be used however is there a more suitable grade oil than this to use?

What are others using in there isuzu box ?

Originally Posted by c.h.i.e.f

What brand of oil would you be running John ? I have been using castrol apx80 in my puma and it seems like a good oil...I was thinking there must be an advantage of running a specific gear oil rather than an engine oil as stated on the box name tag however I'm just not sure what one...

Any synthetic manual transmission fluid. I use Castrol Syntrans when it is available.

BTW never use the term 'gear oil'in place of manual transmission fluid. You need to re-program your brain. Gear oil is not suitable for manual gearboxes in automotive use.

Because gear oil was not suitable, and in the early years nothing better was available, manufacturers specified engine oil for their gearboxes. In later years some changed to automatic transmission fluid.

Oil manufactures have since developed manual transmission fluid (MTF). It has the low viscocity and high viscocity index needed, with additives for the extreme pressure that occurs between mating gear teeth. It is far superior to engine oil and auto transmission fluid.

Lots of people here will tell you engine oil and use it in their LT95 gearboxes. I can't say here that I think they are ...... either that or they are ignorant of the differences between engine oil and MTF and still think MTF is gear oil (gear oil is too viscous and will kill an LT95 after the oil pump gear fails).