Hey guys,
I was just under the REPU, and decided that it would be a good idea to change the transmission oil. The trans in the truck is a 79-80 RX-7 transmission. I checked the workshop manual I have for an 83 RX-7, and it called for SAE 90 oil in the trans. I had two quarts of Redline MT-90 that came with the Corolla, and thought that should be good. I read the back of the bottle, and it seemed okay. I filled the transmission with it. What do you guys think? Will it work?
Also I have three bottles of Schaeffer 293 supreme gear lube that came with the Corolla. it is 75W-90. I was wondering if that would be suitable for the rear differential? The sticker on the hood says the same SAE90 for the differential. Would this Schaeffer oil work for this application?
Redline MT90's a great choice as long as the manual doesn't ask for hypoid gear oil. In that case you should look for Shell Spirax 80W-90.
The manual only said SAE 90 oil for the transmission. How about the oil for the rear axle?
Mazdax605 wrote:
The manual only said SAE 90 oil for the transmission. How about the oil for the rear axle?
Well it says SAE90, see if you can find straight 90 weight gear oil, but that's very hard to find. The best common modern substitute is 80W-90.
So in short the 75W-90 isn't up to the task?
You could but the 80W-90 is a slightly closer match and Redline isn't made for diffs specifically. I think it'd still work fine if you have some left over.
above 0 degrees F. - 90
below 0 degrees F. - 80
So it would seem that 80W-90 will work.
The only real difference will be a little more chatter out of the lower weight. It should not effect longevity, more of a sound dampener in my experience.
Looking closer at the bottle of Redline MT-90 it says it is 75W-90, which is the same as the Schaeffer 293 gear oil. So if the Redline was okay in the trans that calls for the same stuff as the axle then maybe it is okay? No?
I already said I think it'll work fine in the diff as well. Yeah you might get a little more noise when it's cold but that's all.
You NEED a GL-5 gear lube in essentially any rear end made after WW2. MT-90 is a damn fine trans lube, but dont put it in a diff.
Guys, I wasn't asking about using the MT-90 in the rear axle. I was asking about using the three bottles of Schaeffers 293 supreme gear lube 75W90 in the axle. I suppose I will just forget it, and try to find some SAE90 gear oil for the axle. Doesn't sound like it will be easy though.
I'd say, use what you have.
for those that forget, 75W(winter).
Almost like muti viscosity engine oils.
Kenny_McCormic wrote:
You NEED a GL-5 gear lube in essentially any rear end made after WW2. MT-90 is a damn fine trans lube, but dont put it in a diff.
What about transaxles? Lotus recommends it for Toyota C60-series boxes used in the Elise/Exige.
In reply to GameboyRMH:
Transaxles without hypoid gears (subaru mostly) would be fine, I run MT-90 in the C59 in my Prizm.
Mazdax605 wrote:
Guys, I wasn't asking about using the MT-90 in the rear axle. I was asking about using the three bottles of Schaeffers 293 supreme gear lube 75W90 in the axle. I suppose I will just forget it, and try to find some SAE90 gear oil for the axle. Doesn't sound like it will be easy though.
Using 75w90 hypoid/extreme pressure/GL-5 gear oil would be just fine. You wont find a straight 90 for extreme pressure use today.
Use 75W90. Or 80W90. Or 85W140. Or ATF. It'll all be just fine.
Thanks guys. I appreciate the help.
