Redline mt90 problem?
 

I recently changed my trans fluid (6mt) and now Im noticing in the morning when the trans is cold that shifts into 1st and 2nd seem a bit stiffer that before.
I thought it would improve not degrade shifting ease
Car has 43000 mis and prev owner had trans fluid changed st the 36000. The old fluid looked very clean
Any ideas why its shifting harder when cold ?

The 6MT uses MT85, not MT90. That might be part of your problem.

I appreciate the reply however I cant imagine that theres that much of a differance between the two other then heat range .
By the way Im in so fla

That is correct, when using MT90 you will also normally have to a split with MTL. MT85 solves that problem by already being the correct mixture.

At cold temp, since MT90 is "thicker" than MT85, wouldn't that be normal to have a slightly stiffer feel?

This is a very picky transmission. That's why Redline created the special 85 blend. It makes more of a difference than you think.


And I'm in Houston so I'm familiar with the climate.

Your problem is that MT90 is not the correct fluid for the 370Z 6MT. Put the correct fluid in there and you shouldn't have an issue.

Funny how everyone is telling him its the wrong fluid, yet he still disagrees. People people

Always seems to be someone to post a stupid comment and start trouble . If you have nothing useful to add please refrain from posting .
I didnt disagree just questioned the original answer which when you think about it doesnt make sense logically . The weights are very close . I now know it matters so thanks to all who responded with useful info

I just searched my post from several weeks ago which requested info on which fluid to use for the trans and spooler who has the same car as me suggested mt90 which he used . Jarblue did mention mt85 but no one said not to use the 90weight .
I assume spooler is not having issues so I wonder once again whats up .
I guess Ill change it to 85 as see .

Could it be that I didnt fill it enough .It could be a little low .

Dont get your panties all in a bunch. Spooler conditions are probably way different than what your car is in. Hence why he isnt having the same problem you are. Fsm is a very useful tool, if you dont plan or seriously mod your car or track it often then i wouldn't vary off oem spec.

I think thats the best advice Ive gotten . I did a search and Im not the only one whos had this problem with redline .Cant imagine why.

Im going back to nissan fluid

:iagree:

Speaking of the fsm which I found on this site .Theres no index page . Im glad to have it but it tedious to find anything

I use 75w90 for this reason alone. This issue is not new to me. The older cars had the exact same issue all the way back to the 1970's. 75w90 synthetic fixed it up every time.

Many PDF readers allow you to search all PDFs in a folder. Dump the FSM PDFs in a folder and tell the reader to search there.

click on south arks links for the fsm.

i run motul diff, power steering, trans, and brake fluid. Everything runs like a champ.

I used MT85/MT90 mix and it feels much better the before (32Kmiles). Swap it out for a lighter weight if you are not liking it, not all transmissions are exactly the same and you just may have gotten a bad batch. Not much else you can do except try again or deal with it.

I replaced my transmission fluid about a month ago with MT85 and noticed this exact stiffness right away. It's been driving me nuts but I just assumed this was normal. I have also noticed that once it is warmed up 1st to 2nd is very clunky. It bothers me to the point I am debating on switching back to factory fluid. i just passed 12k miles the other day and was not like this at all before the fluid change.

Change it to synthetic 75w90 of your choice. I use Amsoil.

Thanks Spooler, I appreciate it!