bighorn manual gearbox oil

[Lewis]

Hi

What sort of oil should be used in a manual gearbox in a 1995 3.1td bighorn?

My dad recently had the oil changed in his gearbox and now the shifts are harder and not so smooth, particulary when engaging 2nd from 1st and he reckons the garage may have put the wrong oil in.

We also have a 1987 bighorn which has a pretty crunchy 2nd gear as well, ive just presumed the syncro is worn, but now my dad reckons that gearbox might have the wrong oil in it too. ( they were done at the same place)

Seems to be smoother overall after its warmed up, but then sometimes its still a crunchy shift.

Thanks

[geeves]

Book recomends the same engine oil as you have in the engine. However a lot of very modern oils have anti friction additives which can beat synchos. I use Mobil Super which is still 8 bucks at the local petrol station and it works well. A lot of people use ATF which is also good but can leak. A lot of garages put hypoid gear oil in which dosnt make sense as the only gearboxes that ever went in were old english and american ones. No damage is done by putting a thicker oil or fancyoil in but it will take a while to get the coating off the synchros.

[rick1970]

I have tried 75W80 gear oil in both synthetic and mineral, the mineral oil gave a slightly better shift, but still not real good. A guy at the local Holden dealer recons to use 5W30 or straight 30 engine oil, will be trying this next.

[Lewis]

ok, thanks for the info.

So geeves when u say the book do u mean a workshop manual? Where did you get this btw?

When you say beat synchroes do u mean damage them? So you reckon something like 15W40 Delo diesel oil would be a better choice in the gearbox, cause thats what we put in the engine...

Thanks for opinions

[geeves]

It dosnt damage the synchros but it does coat them with slippery stuff which is against the requirments of a synchro . Putting a standard oil in will restore them but it might take a while.
There is a set of manuals sitting in a gmail account that you can get by going to www.gmail.com and logging in as isuzunz password 4jb1turbo
for the 87 you need the trooper 2 manuals and also the 4jb1 engine manual. for the 95 you need the 11 ubs files which you put into one folder then open the first one with izark. Thsese total about 60 meg in size
Do not delet anything. If you only have dial up send me a pm with a postal address and Ill send you a cd with them on

[Lewis]

ok thanks im on 2Mb so dling them is sweet