I'm looking to change out my tranny and diff fluids in the next couple of weeks. I remember hearing a lot about GM Synchromesh for a while, but then noone has mentioned it for a long time.

I want to know which trans / diff fluids are good alternatives to the OEM (if any). For you guys not using the OEM fluids, which fluids are you using and what are you impressions of it over the length of time since you've changed.

-Chris

 

I used the GM fluid for a couple changes, but it seems to only last a few thousand miles. My last change was with Redline MT-90 (not MTL), and it is awesome (when it is not too cold). Since you live in southern Florida, I think it would be your best bet.

Most people use Mobil 1 Gear Lube (I think it is 75W-90) for the rear end.

 

I use the Honda MTF in the tranny. This seems to work best for my kind of driving. Like many others, I use the Mobil 1 syn. gear oil for the diff.
These fluids are so cheap that you should learn how to do the change yourself and do it once a year. The tranny and diff are very critical components of your drive train. I don't mind giving them a little more TLC than what the manual might say. If you track the car, these should be done more often.

 

anybody know of any places that sells the redline oils for cheap? also whats the difference between MTL and MT-90 fluids? actually which fluid would be more ideal for southern california weather?

chris

 

You can get all the Redline products for the best prices I've seen at http://store.summitracing.com/ Then drill down (pun intended) to Oil System for the available oils, and then down to Transmission and Rear End for the tranny/diff fluids. Redline oil, MTL, MT-90, and diff fluid are all $7.95/qt, last I checked. Redline Water Wetter is $7.95/bottle, which is best price I've seen for that. You could also check out the Redline site for local dealers http://www.redlineoil.com/


I'm not sure which tranny lube would be better for So Cal, but I know it's been discussed extensively, so like they say, "do a search." For instance here's the first one from a search on MT-90 https://www.s2ki.com/forums/showthread.php?...highlight=MT-90 This one suggests that MT-90 would be better in more temperate climes like So Cal. You might also consider GM Synchromesh fluid. Personally I like Mobil One 10W-30 in the engine, Honda MTF in the tranny, and Mobil Synthetic Gear Lube 75W-90 in the differential. But because of track use and high AZ temperatures, I'm changing tranny and diff fluid every other oil change.

 

The most important thing is to have a regular change interval. Once a year on the diff and every few years on the tranny seems good.

You can't eat a big meal and go the rest of the week without eating. Same with lubrication.

I like to use Honda MTF and Mobil1 Gear Oil.

 

I have changed my tranny oil 4 times in 19K miles (11 months). If I don't change it every 3-4K miles, I start grinding into 2nd.

The difference between the MTL and MT-90 is its weight. The MTL is supposedly like a 10W-30 (or 5W-30), and MT-90 is like a 10W-40. The MTL would probably be better when its cold, but the MT-90 KICKS ASS when its warm.

 

I found MTL didn't hold up to track days, GM Syncromesh so far seems fine even after multiple track days, and I'll likely try MT-90 for the next change for summer season.

 

I haven't tried MT-90 in my S2000 yet, but I did just put this in my truck this past weekend and I am VERY impressed with what it did for my "cold shiftability" in my Toyota. It is amazing what the difference is.

I have changed my tansmission fluid a couple of times and used Honda MTF and it made a difference. For the rear, I used Valvoline Durablend.

 

So is MOBIL 1 the GEAR OIL CHOICE