Gearbox and diff oil

Rallly

New member
Corey":2ah4qsnq said:
As long as its a GL-5 fluid, then sure. I still prefer Redline personally.


RP website says it can be used were GL-5 and GL-4 are needed. So I assume Royal Purple 75w-90 is okay?
 

Corey

Active member
Royalpurple MaxGear 75W90 - sure (the site claims GL5 or 4)
I wouldn't use their Syncromax 75W90 because its not GL5.
 
This posting is for 2 somewhat different applications. By gear box, I'm assuming that to mean the transmission and front differential. By differential, I'm assuming that to mean the rear differential. Do I have an incorrect interpretation?

For the transmission/front differential, I've always used Toyota P/N 08885-02106 (Toyota Gear Oil Super, a hybrid oil for Hypoid Gears (Differntial) and Syncromesh Trans). It ran $28.04/liter last time I got it. It is labeled as a GL-5 75W-90 oil, and is what Toyota calls out for the transmission/front differential because of the quadruple case setup.

For the rear differential, I've used Red Line 75W-90 GL-5+ Hypoid Gear Oil. That ran $15.50/quart the last time I got it.

The Red Line 75W-90 NS GL-5 Gear Oil brought up may be a good option to the Toyota Gear Oil Super in that it is made for transmissions and tranaxles in that it lacks friction modifiers to balance slipperiness (synchros needs some kind of friction to spin up when pressure is applied to them) but is still a GL-5 oil for hypoid gears in differentials. The quadruple cased Celica system has both synchros and hypoid gears within the same oil bath, so it is pretty important to get a hybrid oil that balances out this unique combination. I know the Toyota Gear Oil Super does just that, as it was designed for this quadruple case design Toyota uses. The Red Line 75W-90 NS GL-5 Gear Oil may be acceptable as well - and for those ST185 owners that use it in their transmissions, I haven't heard any negative consequences yet.
 
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