4x4Wire TrailTalk

manual transmission lubricant

Posted By: Anonymous

manual transmission lubricant - 02/06/01 08:00 PM

The 90 4door Montero that I recently bought to replace my V6 Raider is driving better in every way except for the transmission. 2nd gear is really irritating me. Recent posts indicate that I am far from alone. Anyway, I have seen Red Line MTL recommended to smooth it out. It certainly makes my Miata happier (2nd synchro worn out there too; both vehicles over 100,000 miles), but I have also seen posts that indicate GL4 to be very bad for Montero synchros. Those posts said GL5 is needed. Checking the Red Line web page, I see that MTL is a GL4 lubricant.<P>Comments? Recommendations?<P>Thanks,<BR>-Rod
Posted By: Augie

Re: manual transmission lubricant - 02/06/01 08:06 PM

Nope you got it wrong. GL4 are preferred anytime a syncros are present. At least on Japanese manual tranny. <P>GL5 are preferred for Hypoid gear use such as differential gear. <P>You would be fine with MTL or MT-90. Use MTL if you live in colder climate, Use MT-90 if you live in warm climate.
Posted By: Maciek

Re: manual transmission lubricant - 01/23/17 04:21 AM

So, what's everyone currently using, anything available off the shelf at the local auto parts? Everything seems to be GL-5/for limited slip...
Posted By: Lha1988

Re: manual transmission lubricant - 01/23/17 06:42 PM

GL5 will eat up your synchronizers,as they are bronze. I couldn't find any in my area,and use 20w50 motor oil with great results. I'm sure that I will get some feedback on this,but the shifting improved a lot,and after 350,000 miles,that's good.
Posted By: 4x4Wire

Re: manual transmission lubricant - 01/23/17 11:06 PM

85w gear oil. According the back of the bottle it is good for GL3, GL4 and GL5 applications.
Posted By: Lha1988

Re: manual transmission lubricant - 01/23/17 11:19 PM

Most I've seen said good to top off when GL-3,4 are used,not to replace. Synthetic may work,though.
Posted By: marksroberts61

Re: manual transmission lubricant - 01/24/17 05:47 AM

Sta Lube (?) At NAPA is the only GL-4 lube I have found on the shelf. Stay away from any that say GL-4 & GL-5 compatable, they are Gl-5 oil, admittedly a better high pressure gear lube, but hard on synchros. There has been lively debate here about this, but Mitsu directly specifies GL-4 for the x-fer case with GL-5 for the diffs, must be for a reason.
Posted By: Maciek

Re: manual transmission lubricant - 01/25/17 09:28 PM

I keep reading the same thing about GL-5 and brass synchros. I'm glad I did some research because both My user manual and factory service manual specify "GL-4 or higher" for all fluids. Guess I'll order a few quarts of MTL or MT-85, or go cheap with a jug of the StaLube 85-90, seems a little thick but reviews are good. The old stuff in there now takes a few mins to warm up when it's freezing anyway (prolly used the same stuff last time, but that was a loong time ago when i first got the truck).

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Thanks,
~Mac

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Posted By: PHIL_

Re: manual transmission lubricant - 03/21/17 12:20 AM

GL5 in front and rear diffs, GL4 in tcase and trans. Redline MT90 is GL4 and puts those syncros in their happy place.
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