Diff and Tranny Lube for 2nd gen?

A

AS-RACER

New member
I haven't raced my 2nd gen ITS RX7 in a while and I can't remember what to use for the diff and tranny. I have a 512 LSD from ISC Racing. Is Redline MT90 ok for my diff or should I use 75W 90 in both?
 
I haven't raced my 2nd gen ITS RX7 in a while and I can't remember what to use for the diff and tranny. I have a 512 LSD from ISC Racing. Is Redline MT90 ok for my diff or should I use 75W 90 in both?
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I use MT90 in the trans and 75/90 Mobile 1 in the diff. Never lost one yet-(knocking on wood as I speak).
 
MT90 tranny, Mobil 1 synthetic 75-90 diff, just went from Mobil 1 15-50 to Idemitsu 20-50 for motor last oil change. I change them after every long weekend (3 hours or so), not sure if that is necessary though. The rear is the 5.12 with clutch pack, not torsen.
 
Try http://www.swepcousa.com The only gear lube for Mazdas.
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Dick am I missing something? I didn't see a GL-4 lubricant. For sure in the tranny you want a GL-4 lube.

I've used Amsoil for many years. They make a GL-4 for trans, several GL-5's for the rear end, and a 20/50 racing high end engine oil, all synthetic.
Some seem to have problems with Redline in the tranny, I've used MT90 lots of times with no issues. For sure don't use MT or MT90 in the rear end as Eagle7 said. Mobil one is used by many but I'm an old Amsoil dealer (since 1981) so I stay as loyal as practicle.
I know Jim Susko has a tranny oil he swears by, can't recall the name it could be a swepco product.
 
since our equipment is pretty similar from miata to rx7 i'll drop in my data point.

i think M1 75/90 is safe to use in both gearbox and diff....though i really don't have any data to back that up.

i did pick up 8qts of MTL for miata transmissions on sale at advance auto parts for $5/qt that will probably get swapped in before year end.
 
I am currently using Amsoil 75/90 in the trans and Amsoil 75/140 in the rear end. I have also used Mobile 1, Royal Purple and Valveoline Synthetic. I've always used a heavier wt lube in the rear end. I switched to Amsoil when I started to notice more wear in the rearend. So far so good!
 
Swepco is the only gear lube I've ever used that will not eat "sinkrows" in a mazda tranie. Try it / you'll like it! [/b]
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Dick, please elaborate. I seem to get about 2 years out of a trannie before the synchros are shot. What's your experience with Swepco and with other brands? Which Swepco lube do you use? I see they have internet ordering, but no prices - what does it cost?



Thanks,
 
5 gal of Swepco was given to me by a Porsche shop in Denver 15 years ago. Before that synchos would last from one to five races max in our GT-2 Rx-7. After the switch, we never had any more problems, and replacement was only at overhaul, when necessary of the tranie. Porsche people really like it, to a point of Swepco, or park it. As to the type, well I put it in to smaller cans, and dumped the orginal can. Sorry. Talk to Swepco. I'm sure they know what the racers use. Its like that black lube that Ford used to sell for Detroit Lockers. Nothing else worked as good and now Ford quit selling it. I'm sure Swepco could cover it though.
 
The issue is one that has been discussed before, here and in other places. Gear lube made for LSD's are
GL-5 grade lubricants. They are designed for the exceptionaly intense shear forces in the differential. They also include a special LSD additive package for the most part. This is what is causing the wear to your syncros. Were basically over lubricating our transmissions when we use most GL-5 lubes in them. The syncros require a little more friction. I'm going to give the swepco product a try, right now I'm using this http://www.amsoil.com/StoreFront/mtg.aspx this is a new product for Amsoil, before that I was using Redline MT.
 
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