What diff and gearbox oil

**vtrfirestorm** · 26-01-2006, 07:40 AM

Hello and happy Aussie day,

I am putting a 20V and T50 into 78 KE35 and was wondering what is the correct grade or type of oil for both gearbox and diff.
The original diff is in the car and i do not plan to change it at this point so is there anything i can do that will help its chances of lasting?

Also i am at engine managemnet computer decision time - your thoughts would be great re what is the best and what is the best value.

cheers peter

**limbo** · 26-01-2006, 09:59 AM

I've used redline for gearboxes and they are quite good. They are on the expensive side though. I'm sure redlinealso make diff oil.

As with engine mgmt, try to get one that does not require modification of the dizzy teeth. That way it will be easier to start. I had a wolf 3d and that was a bad experience in my 20v cos it was a hard starter and used heaps of fuel i was using the car for daily driving so i hated it. It did though make 92kw at the wheels.

**Rallystanza** · 26-01-2006, 10:22 AM

As far as diff oil goes, I would recommend just a normal weight 80-90w mineral based oil.

I have found Penrite is great for diff oil and Catrol for gearbox oil.

Gearbox will be fine with just a normal gearbox oil of the same weight, but I would however say that the Redline Lighweight shockproof gear oil (the fluro blue shit) is quite good. I had a typical stiff shift in an otherwise very good condition R154 Gearbox and this oil has made the shift very nice at all temps.

It also depends on the severity of the driving.

On the topic of engine management, I am also currently going through the decisions and I have narrowed it down to Autronic, models SM2 or SM4. I am just trying to determine which model will do the best for me. I will be using this in conjunction with the Autronic CDI unit. Its expensive but it does all the right things, with functional Auto Tune and also things such as anti lag, launch control and traction control. Traction control is something i like the idea of. Tuners like it as its easy to use, a happy tuner is a good tuner i reckon.

Good luck with it.

Jeremy

**Jonny Rochester** · 26-01-2006, 10:22 AM

Here is my formula for gear oils:

GL-4 = good
GL-5 = better
GL-6 / GL-5* / LS90 = best

GL-4 is for most gearboxs and transfer cases where a hypoid gear is not used. So this is good for the T50.

GL-5 is better, and can be used in diffs where a hypoid (90 degree gear) is used. The 90 degree gear creates more friction so the better oil is needed. This is used for the open corolla diff.

LSD oil, called LS90 in the Valvoline brand, is for clutch pack LSDs where extream pressures can cause wear very quickly. This is used for a factory Toyota or TRD clutch pack LSD. Non-clutch pack LSD types like TorqueSensing and viscous coupling do not require LSD oil.

Weight:
The thickness of the oil in diffs and transfers does not make much difference. Generaly the thicker the better. If the oil is too thin in the diff, it may make more noise. GL-5 is often sold in a 80w95 weight or similar, and does the job.

The thickness of oil in the gearbox is more critical. Too thick and you won't change gears nice. The GL-4 you buy will be right for most gearboxes, 75w85 or similar. This is OK for a T50 in good condition. If the T50 is old and not shifting right, you can use Dextron III which is a auto trans oil and thinner. Don't stress, it works. Some cars have used Dextron or engine oil for the trans from new.

Brands:
It makes no difference, oil is oil. Don't waste your money.