GL4...GL5 gear oil??s

So this weekend I changed all my drivetrain fluids. I used valvoline gear oil just the normal 75w-90 valvoline non-synthetic. Now I didnt know that it was a GL5 gear oil. Im planning on changing my tranny fluid to penzoil syncromesh ASAP, but I was wondering if it would be ok to leave the valvoline GL5 gear oil in the rear end and transfer case.

 

[iceman69510]

GL5 is ok for the rear diff. Tranfer case also calls for GL4. I'm sure some have used GL5 in the transfer case though.

 

[Brianawd]

Quote:
penzoil syncromesh ASAP




Bad idea.

Use redline MT90,Mitsubishi Diaqueen 75w85. RP 75W90.

 

why is penzoil syncromesh i bad idea everyone seems to rave about it.

 

[alansupra94]

We rave about it inside of the transmission, not the transfer case. The main reason we do is it is the same exact thing as GM Schromesh which is the best for our transmissions. For our transfer cases and rear end, I would go with shockproof. Redline MT90 is really for the transmission.

 

[Dan D]

Brians comment was in regards to the tranny.

Syncromesh doesn't offer good gear protection and wears syncros faster - That is why a lot of people don't like it (especially transmission builders). As horsepower numbers climb, the amount of protection afforded to the gears is a concern and you should use a good quality gear oil as Brian mentioned.

For what it's worth - I ran penzoil syncromesh in my transmission for 85k miles with no problems. It shifted nicely. Since having it rebuilt and upping my cars HP a good bit, I have switched to MT-90 for the added "cushion" the gear oil provides.

 

[bazeng]

I have Redline Heavyweight shockproof in my xfercase and rear diff (red stuff). My rear diff has a mech lsd so lsd additive was added.

For gearbox fluids I have always used DIAQUEEN + mitsu lsd additive (mech lsd in mine also).

 

Yeah i gotcha about the syncromesh for the tranny only...my only plans for now would be to replace my turbo with a 16g and run 16 psi. I wont be drag racing the car ill be using it mostly for autox and as a dd.. and can i leave my valvoline gl5 gear oil in the transfer case and rear end then. Thanks.

 

[donkeylips]

I had a tranny destroy itself on the highway running MT-90 and when I swapped the new one in I just filled it with synchromesh. My friend owns the car now with some more miles on it and no problem. I've also heard that a mixture of gear oil and synchromesh works well and that's what I plan to run in 108.

 

[SleepinGVR4]

I guarantee it wasn't the MT-90 that destroyed your trans. Synchromesh is actually hard on the synchros like everyone said. But if your synchro's are already on their way out I find synchromesh does help the trans shift better. And since the syncho's are bad to begin with who cares if you add synchromesh.

 

any fully synthetic GL4 75W-85 is suitable to use in the gearbox and transfer case

 

[DynastyLCD]

im surprised nobody mentioned lightweight shockproof (blue color) for transmission use. i have been running that in the trans and tcase with great luck. was recommended by an awesome local trans builder. i plan on switching to the heavyweight shockproof (red) for the tcase, i run that in the rear end already. it says good for LSD use, and ive ran it straight up in my 4 bolt LSD with no additive, no issue. maybe it would be worth it for the LSD additive. worth a try i suppose.

 

the tre website said you could run gl5 gear oil in the transfercase and rear end. So im just going to leave it for now, minus the transmission fluid.

 

[donkeylips]

Quoting SleepinGVR4:
I guarantee it wasn't the MT-90 that destroyed your trans. Synchromesh is actually hard on the synchros like everyone said. But if your synchro's are already on their way out I find synchromesh does help the trans shift better. And since the syncho's are bad to begin with who cares if you add synchromesh.



Oh yeah I didn't mean to imply that. I would run MT-90 again. And I agree with what you say about Synchromesh 100% based on what I've heard and from running it in a few cars vs. MT-90. Not good for the trans long-term, but can ease shifting.