Differential fluid in 1998 Corolla

1998 Corolla with a 3 speed auto trans. I've established that its separate fluid for the transmission and the differential / transaxle. The differential is filled with a plug facing the firewall. Online I have found that the fluid is Dextron III auto trans fluid for the gearbox, but what drained out to me looks like gear oil - maybe 50 weight. Anybody know for sure. Thanks Brian
Reply to
SuperBK
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Dunno.. I'd want to make sure.. And it does sort of sound like it had gear oil instead of ATF.. ATF would be reddish, and would have the usual ATF smell. Gear oil will usually be yellow-brownish and have a totally different smell.

What makes it confusing is the manual says that you use ATF in both, but some people like you, claim that there was likely gear oil in the differential. Myself.. I think it likely was gear oil.. Back then, most were separate, and many differentials did use gear oil I'm pretty sure. But 50 weight seems to be hard to come by, and most is the usual

70-90 or whatever weight.. So you then worry if that might be too thick when it's cold.. It is a dilemma that's hard to get a straight answer to.. But if the old stuff was gear oil, I'd be able to tell from the smell. It doesn't smell anything like ATF.

On my 4 speed, they are connected, and the whole mess runs on ATF.. So I guess ATF is capable of keeping it lubed.. But I bet gear oil is a bit better as far as gear wear, etc.. I think one reason they are now using ATF for the whole thing is for better gas mileage. ATF is thin, even in cold weather.. That's also why mine uses the light 5w-30 oil.. And the newer ones seem to be going to even lighter oil. I wish I could find some 50 weight gear oil as I need to change the oil in my old Ford truck, and it prefers 50 weight gear oil. But.. it seems hard to find these days.. I might try the dealer.. They used to stock it I think.. Mine has the old T-18 four speed.. It will on 90 weight, but it's really too thick for winter.. It likes 50 better.

Reply to
NM5K

Try a farm/tractor supply store, if there's one in your area. One near me has 50 weight by the 5 gal. bucket !

Reply to
Y.T.

Thanks, will continue to research this. I thought the same thing - ATF should be able to handle it, but maybe gear oil would be better. I think most of these units are filled at the factory and then never serviced for the life of the car.

Reply to
SuperBK

I have a 1986 Corolla with the 3-speed A131L automatic that keeps the trans= mission fluid separate from the differential fluid, and the factory manual = specifies Dexron for the transmission and Dextron for the differential. So= me old FWD VWs with automatics used Dexron in the transmission and 80W-90 g= ear oil in the differential.

Gear oil and engine oil are rated by different viscosity ratings, so 50 wei= ght gear oil is pretty light, while 50 weight engine oil is thick and about= like 80W-90 gear oil. Dexron is roughly like 10 weight engine oil. Here'= s a table showing different viscosity ratings:

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Reply to
larrymoencurly

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