The car is a Mazda Miata. Owners manual calls for 90wt. gear lube in the diff. I can't find any straight 90wt. lubes. So the question is can I use a 75-90wt. lube? Mobil 1, Valvoline etc. make a synthetic 75-90wt. and a synthetic would be my preference if that weight can be used. What do you guys think?
What weight is best?
- Thread starter Mar57
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I would check what the dealer has. If its 75-90 or 80w90 as well, then use what you want. If they have a straight 90wt( i doubt it) buy that.
Any 75w90 or 80w90 is fine.
"They don't mean straight 90wt."
If they didn't mean it, why print it? That's what the manual says so why should someone have to try to interpret what they mean?
If they didn't mean it, why print it? That's what the manual says so why should someone have to try to interpret what they mean?
Any 75w90 synthetic will do.
Agreed, never had a lubrication caused problem out of a 75w-90 or 80w-90 in my 91, even with the 1/2qt capacity and the track beatings it took.
What year is the Miata? In the 3 owner manuals that I checked NA,NB and NC.
The specs were...GL-5 SAE 90 80w-90 and 75w-90.
Everyone I know is using 75w-90.
The specs were...GL-5 SAE 90 80w-90 and 75w-90.
Everyone I know is using 75w-90.
Less weight is definitely best. I am trying to loose weight.
Many Japanese cars call for SAE 90 gear oil, but I never had a problem when replacing it with conventional 80w90 or synthetic 75w90. In the repair shops where I worked, we just used whatever XXw90 gear oil was on the shelf.
Always synthetic in that heavy weight oil, doesn't matter the weight as long as it's close, which it is.
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