barneyb

This is true for engine oil but is it true for gear oil? Having waxes and other impurities in gear oil could be a benefit. Finding a better additive package is also wisdom coming from engine oil.

kyoo

iTrader: (29)

i would assume so. i've swapped to redline 75w90 gl5 in t-case and rear differential with zero issue. but i also flush all my fluids annually, since it's an autox/track car

Evo9isLife

All of the reasons for group 5 being better for engine oil are the same reasons why it is better for gear oil.. Better detergency, film strength, high heat & high shear stability, lubricity and the clinging effect that esters have on metal surfaces. The fact that redline and motul also use a ton of zddp and moly additives is a bonus.

whiteEvo08Y

iTrader: (5)

Hey Kyoo. quick question, you say you use 75W90 in the T-case and Rear Differential, My drivetrain with fully build by Shep. I am going to use 75W90 in the T-case and rear differential, what would you recommend for transmission fluid? Where I live it goes down to -15 if that makes any difference. MT-85 75W85 GL4 OR MT-90 75W90 GL-4?

Thanks

kyoo

iTrader: (29)

kind of a cop out but i'd go with whatever the builder says to. 75w85 is for the 6 speed, idk if you have the 6 or the 5, but either case, if it gets that cold where you are that's what i'd personally do, that's unbelievably cold. i run 75w85 gl4 in my 6 speed which was "built" by TRE.

SoSoEVO

iTrader: (5)

Still running Redline gl5 75-90 over Diaqueen Kyoo? I'm about to a flush on my trans, tcase, and rear diff.

Thanks!

kyoo

iTrader: (29)

me, personally? i am, yes. i'm near stock power levels, with very mild bolt ons though, to each their own. the trans needs GL4 btw.

SoSoEVO

iTrader: (5)

I'm stock as far as power level goes...I read through the thread and standard redline gear oil slightly edges out the the Diaqueen with phosphorus and boron correct? So for just a weekend car with track days often do you recommend the thickness of the Diaqueen or would the standard redline be fine? I know you mention you auto x your car often but idk if the heat generated is the same as a longer road course.

Ahhh ok so the trans needs gl4 and tcase/ rear diff used gl5?

Thanks in advance!

kyoo

iTrader: (29)

i've run redline 75w90 with zero issue, on track and autox. i flush my fluid annually, which may be overkill though - regardless, i flush more frequently than most anyway. heat generated on road course is far, far higher.

trans needs GL4, either 75w90 for 5spd or 75w85 for 6spd

SoSoEVO

iTrader: (5)

Sweet thanks man I appreciate it! Haha that's not overkill that's just proactive maintenance. Last question the gl5 redline I'm only seeing "ns". Is that what you use for the tcase and rear diff?
https://www.redlineoil.com/gear-oil-...-transmissions

Update:
Never mind I found it under the "gear oil for diff" section.

kyoo

iTrader: (29)

I do not use the NS gear oil personally.

heel2toe

iTrader: (41)

Jon@TRE has the Redline fluid as a recommended fluid for the xcase but specifically says to not use the NS.

SoSoEVO

iTrader: (5)

I found the regular gl4 redline gear oil (non ns) I was just looking in the wrong section on redline's website. Thanks guys!

LetsGetThisDone

iTrader: (1)

GL4 Gear oil is for the TRANSMISSION. NOT the transfercase.

The tcase at minimum needs GL5 75w90. TRE recommends 80w140 GL5.

If you put GL4 fluid in the transfercase, you will wipe out the gear set in short order.

kyoo

iTrader: (29)

right, it can be confusing because "trans"mission & "trans"fer case. GL4 in transmission, GL5 in transfer case and rear diff.

I did actually accidentally put GL4 into the t-case once, be careful as the bottles look identical. I flushed it out immediately for GL5. I also ran some lightweight shockproof in the t-case with no ill effect, but decided to roll with the GL5 after doing the test and seeing how closely redline's GL5 additives matched with DQ's.