Here's an anal question...

I want to change my gear oil to MTL-90 to try and smooth out shifting. It's really notchy and I can't engage 1st sometimes, and reverse ever on the first try. Will this help? It can't hurt I suppose.

Will this void the warranty or will they even check if I bring it into the shop. They say that the new oil needs to be of a certain quality. :confused:

The MTL-90 (Redline) is a GL4 oil and the manual calls for a GL5 oil. Whether or not it can be proven that you're using a GL4, I have no clue.
Personally, I wouldn't risk it.

Dennis

Bluesubie, Thanks!

Does anybody know if they can or will check whether oil is GL4 or 5 rated? :confused:

Nevermind...I found out that MT-90 is Gl-5 Rated! Problem solved!
:D

[ June 14, 2001: Message edited by: phred's RS ]

Subytechmaster - if he's referring to Redline it is a multi-vs. That's just the name.
But it is a GL4.
From Redline:
MTL® Manual Transmission Lubricant
a 70W80 GL-4 gear oil (SAE 5W30/10W30 engine oil viscosity) designed for use in manual transmissions and transaxles. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting.

MT-90 Manual Transmission Lubricant
a 75W90 GL-4 gear oil designed for use in manual transmissions and transaxles. Provides excellent protection of gears and synchronizers and its balanced slipperiness provides a perfect coefficient of friction, allowing easier shifting.

If you want to use Redline then 75W90NS for tranny and 75W90 for rear diff.

Both are API GL-5 75W90 rated (correct spec) and the NS version is suited for ease of shifting (doesn't have LS modifiers).

Glenn

Dammit! So I should change the MT-90 I put in a few weeks ago to 75W90NS? There goes $40!!!!

I guess I should start reading bottles and stuff huh?

Yeah, just read the owner's manual and the bottles.

Or call Redline.

Glenn

According to Redline's website MT-90 is GL-5 oil? Their description makes it seem like a perfect fit. So I wouldn't go switch out you oil until you read their site.

Just put Redline in the entire car. Just to make sure I called them and talked to the Tech-rep. He suggested that I use 75W90NS in the Transmission, and 75W90 for the diffs (Just what Glen said)

I can say that it helps to smooth the shifting up. (I accidently hit the rev limiter when I got it back from the shop.....before... I knew from feel when it was close...not any more).

Cheers

EddyL.

I strongly recommend you use a multi-vis gear oil. If you run a straight 90wt you will find more problems when cold, hard shifting , etc.

This question came up several times and many people had different opinions on it. Personally I dumped the Redline 75W90NS for some stock stuff as the Redline was too thin when it got warm. I was getting a lot of 1st gear crunching.

Either way, the MT-90 according to Redline isn't the correct oil for the tranny. The MT-90 has friction modifiers while the 75W90NS does not. The friction modifiers are used to help the synchros/limited slips work better. However, depending on the tranny, the modifiers may not work, as is the case with are tranny based on Redline's recommendation.

I forget who it was but they did a mix of 75W90NS and 75W140NS and found that it was much better than the straight 75W90NS when warm.

According to Redline's Website: "...If a 90W GL-4 or SAE 40, 10W40, or 15W40 is required, MT-90 may be used. If the transmission or transaxle requires an SAE 90 GL-5 gear oil, then Red Line 75W90NS or 75W140NS Gear Oil may be used..."

So, to answer the question about voiding the warranty, yes, putting a GL-4 oil in when a GL-5 is required can void it.

Reverse gear will never be great because it has no synchro and I believe it is straight cut?

- Ken

phred - Where are you getting info that MT-90 is a GL5? In my post above I copy/pasted from the Redline's website. Try looking again.
Yes it has been recommended because it works well, but it's a GL4. If that concerns you, use the 75W90NS in the front. It was suggested by Redline to mix the 90 with 140 if you're getting grinding.

Personally, I use the Amsoil Standard (not Series 2000) in the front with no problems. A big improvement with sub-freezing shifting and no grinding at any temp.

Dennis

i dont' have great experience with redline 75-90NS stuff. Like other says, it grinds gears as weather gets hot.

Mobil 1 seems to perform to my expection.

How much 75W140 and how much 75W90NS? What is ratio to mix these? And will this combination turn to sludge in the extreme cold like the stock stuff does?

Fred,
Check PK Motorsports replies in this thread (http://www.i-club.com/forums/showthread.php?threadid=30285&referrerid=767).

The 140 has a pour temp of -49F (same as the 90), so my guess is it should be fine.

Dennis