Most people said in the past when I was running Castrol GTX2 that it is bad oil.
I did'nt listen.Apparently it causes sludge.
My uncle's 1991 Mercedes 230e ran it for 700 000km. Only used 500ml oil per 10 000km. Gasket blew at about 500 000km. No ridge at all. It saw 5000rpm frequently because it is a heavy car struggling to pick up speed.
At 100 000km I did a sump service on my VW. It used only Castrol GTX2 it's whole life.The sump was so clean you could eat from it. No sludge at all.

I am running a good quality mineral oil in my street, hard driven, A12GX motor.
Engine is still fine. You can basically use any GOOD quality oil, just keep engine temp at normal as it will start to break down the oils quality when subjected to extreme heat.
Are you planning hillclimbs or track races?
Hillclimbs don't last very long. I will reccomend a semi synthetic.
For race purposes that subject oil to heat and stress go full synthetic.
You cannot go wrong with Castrol synthetic.

royal purple ehh plenty of $$$ but ive got a practical test in one of the street commodores magazines that says that it is just as good as oils half the price
im actually running castrol edge 10-60 not the other one that i had previously stated so do you think that it would be suitable for my A series?

I am a fan of Royal Purple

dodgeman you are basically correct with the syncro's and the bearings and with the second gear thing i dont have a problem ive even changed from 1st to second with no clutch but plenty of foot brake and lots of head movement it wasnt fun but the bad thing is that after i went back to 1st i did it again ( i hadnt been in the car for a while and wasnt used to the small pedal box )
to cut the story short there was no damage done to the box even though i shifted at 7500rpm after a 6000rpm launch (hillclimb start) and i think that it was mainly due to the lsd oil leaving a film on the gears whilst still keeping a loose box with the atf oil.

there's also that stuff for diffs for lsd's i ithnk it's basically really thin gear oil like atf, but designed to mix with gear oil. i've done it and never had any problems, other than breaking tranny cases, but it wasn't oil related.

Quote: Perhaps your Grandfather is onto a good thing. Without ever trying it, I always had it in my mind that ATF & Gear oil didn't mix, but like I said, I never ever tried it.

Back in the 70's we used a large number of small digging machines that used a wet clutch in the fixed-reduction drive housing. We eventually washed out the gear oil [later, engine oil] with kero before filling with ATF. This was the final cure for severe clutch drag & it did no harm to the gears or bearings.

One of the problems I have always found with Datsun gearboxes is slow synchro's into second when cold. This always improved when fully warmed up, so perhaps Grandad just might have the cure as his 'secret formula' would result in a thinner viscosity lube than straight SAE 90 gear oil.

Penrite HPR-15 all the way... HPR-30 if your engine is a little tied.

Have been using it for many years without a problem. It holds it viscosity and colour very well.

benny

i have been told about this for gear box fluid as well. my mechaninc was about to put trans fluid with metho or kero and the recomended manual fluid into my soprtivo before i sold it to remedy the shifting issues they suffer from.
did it to my datsuns and never had an issue (have not done it to this trans yet, so that may be an issue for me)

as for oil, hpr 30 is highly recomended and ised by me int he past. tried sheel sport 25 60 last time and its crap... too thick for my motor. will change to hpr 30 again soon (before datnats) but castrol gtx 3 is good for a 20 50 as well

Ford recommends ATF in the T5

Can't hurt I guess as long as there is suficient fluid level
Some boxes don't run much fluid so I wouldn't use too thin an oil in that instance

what do you think of running magnatec in race mode or would i be wasting my time?
also my grandfather being an ex motor mechanic has been helping a lot and in my 60 series 4 speed we have been running a mixture of 1 third automatic transmission oil to 2 thirds lsd sae 90 gear oil. this give the gearbox an awesome slipery feel and easyer gearchanges what do you guys think of that also
cheers kurt