Gernby

I have been searching for the right tranny oil for almost 40K miles. Almost every oil I have tried has been really nice for the 1st 500 miles, but they always seem to flake out. I have been changing the oil every 3K miles, and each time it goes from feeling worse than ever, to better than ever.

Up until now, the oils I have tried are (in order from worst to best):
Honda MTF
GM Synchromesh
Redline MTL mixed 50/50 with Redline MT-90
Redline MT-90

Redline MT-90 was easily the best during the warm months and on the track, but it was terrible for daily driving in the cold months.

My last change was over 2K miles ago, when I tried GM Synchromesh Friction Modified. It was similar to all the others in the beginning (perfect), but it was MUCH better than MT-90 in the cold. Where it really started to shine was at a recent "Test and Tune" autocross, where I did 25 long (~80 second), fast (>100 MPH) laps with only 1 cool down. I didn't get a single grind, and it was perfectly smooth. With about 2K miles on the oil, I went to a track day. My expectations weren't as high for this one, considering the oil's age. I am extremely pleased to say that it was just as perfect there. I did 4 20+ minute sessions with only one grind. However, I can't blame the oil for that grind, since I was shifting into 4th at corner exit with a ton of lateral force on the shifter (holding myself in the seat). I have made this same mistake (4th gear grind in corner exit) several times with new MT-90.

I will continue running this oil until it starts shifting poorly. I expect that this will be my longest tranny oil change interval in 30K miles. I may still go back to MT-90 in the summer, but I will definitely use GM Synch FM next winter.

BTW, I couldn't get this oil at the Chevy dealer. I found it at a Cadillac dealer.

jeffbrig

gernby, what temps do you consider "cold" where the MT-90 wasn't performing? <50deg? <40?

Gernby

With MT-90, when the temps are in the 50's, and the car has been sitting outside for a while, the tranny feels REALLY notchy. When the temps are in the 40's, it is downright hard to drive.

I doubt it would be much of an issue in Florida, but I think it is possible that GM Synch FM could be better than MT-90 even in warm climates. Time will tell...

derwood03

Gernby-

Since you have tried different combo's , I wonder are you going to try the NEO trans fluid?

Gernby

I haven't heard any good reviews of the NEO tranny oil. I also think I have found everything I've been looking for in an oil. Even if GM Synch FM doesn't hold up in the summer, MT-90 does. I wouldn't mind switching tranny fluids 2 times per year.

Road Rage

Gernby: Excellent anecdote, certainly should be of interest to MY03 and earlier folks.

Info:
GM partno. 88900399
Syncromesh FM (for NV1500 trannies)
Semi-synthetic base

It was developed specifically for New Venture 1500 TRUCK transmissions.

Not sure it is a good choice for MY04's until we see how the carbon synchros fare with it.

NEO is much too thin IMO - it is watery. I still cannot believe its specifications on their website are real, because they are half again thinner than even ATF! Plus, anyone who misspells kinematic has no SOLE (that is a pun, by the way: Society of Lubrication Engineers). I let my membership expire when I got my EE degree and IT engineering career, but am still a member of SAE and AES - a coincidence they use the same letters.

I have contacted the company Lubrication Engineers by the way to see if they make a product worth considering. They make terrific oil and gear lubes.

www.le-inc.com

Project SSAP1

what oil is good to use below 40??? or am i just fcuk'ed??

Gernby

My point is that GM Synch FM has been great down to the 20's for me.

Project SSAP1

hummmm...i just put in the friction modified version of the GM synchormesh this past weekend...and it seems to do ok for when i first start the car in the mornigns and drive off (i live in NJ and its about 30 over here..but i still get that notchy feel if i shift before 4k rpm...maybe my shifting is just f'ed up...and now its only used to feel ntchy with the 1-3 gears...now i feel like its happening in 4th...i dont what the hell the deal is...i just cant wait til summer...this cold weather sucks IMO for this car

Road Rage

Projext SSAP1 - think of your car as a beautiful woman - she may take a while to warm up properly, but a lot of love and a little patience will pay off.