Gearbox and Diff Oil Quantities

[rascal]

I've found the new Penrite Pro Gear GL4 better than the Redline MT90 in my 6 speed.
https://penriteoil.com.au/applications/car-4wd/gear-oils/pro-gear-gl-4-75w-90#/

Thats the stuff I just put in mine. (was MT-90 also) First test will be at Wakefield in two weeks..

[manga_blue]

I've found the new Penrite Pro Gear GL4 better than the Redline MT90 in my 6 speed.
https://penriteoil.com.au/applications/car-4wd/gear-oils/pro-gear-gl-4-75w-90#/

Likewise on my 5 speed, for non-competition work at least. I haven't tracked it with that oil

[madmort]

Purchased 2.5lts of Penrite Pro Gear 75W90 GL4 today for my 6 speed. Sounds liked and it's Australian.

[ianoz]

First test will be at Wakefield in two weeks..

Post up how you find it compared to MT90 on track please

[RS2000]

I've found the new Penrite Pro Gear GL4 better than the Redline MT90 in my 6 speed.
https://penriteoil.com.au/applications/car-4wd/gear-oils/pro-gear-gl-4-75w-90#/

My above observations are in a track only car.

[ianoz]

bought a couple of bottles while the specials were on. Give it a try for next event

[madmort]

Changed gearbox oil this morning to Penrite Gear Pro 75W/90 GL4, only travelled about 50ks but see no discernable difference in changing from 1st to 2nd and 2nd to 3rd gears in my 6 speed. still feels notchy.
I don't know what was in it previously but this oil no different. Thought it may have been a magic elixir, but it isn't.

[rascal]

First test will be at Wakefield in two weeks..

Post up how you find it compared to MT90 on track please

My impressions, post Wakefield, I would put the GL-4 at the same level as MT90,(which is/was my gearbox oil of choice)
I have a long angled MR shifter so action is better than most 6 speeds, but the box felt just as good on the GL-4 as it did on the MT90.
No difference in shift feel or quality. In fact if I didn't know better, (cos I changed it myself) I would be hard pressed to guess if it was MT90 or GL-4 in there...

So thumbs up for me, and I'll stick with the GL-4 from now on, even if only cos Penrite is an Australian company vs the American Redline..

[ManiacLachy]

A lot of the Americans on the big forum rave about Ford Motorcraft gearbox oil, unicorn tears, but for the life of me I can't find a local distributor of it.

https://fab9tuning.com/ford-motorcraft-full-synthetic-manual-transmission-fluid/

[rascal]

Very much depends on your requirements/usage though.
Raving about cold shifting improvements is all good and well, but if it comes at the cost of increased wear when the oil is hot then not so good.

What oil I put in my track car gearbox is not necessarily what I would put in my daily driver gearbox, as the requirements are different.
I couldn't really care less about cold shifting in the track car, and very much care about hot performance/protection.
Likewise cold shifting in the daily is more important to me, and hot performance less so, as the box rarely gets hot in the daily.

[madmort]

My requirements of gearbox oil are for an occasional daily, going from cold to hottish in a day. I'm not racing and wanted my shifts to be smoother for my sedate ( compared to track) and, to me, spirited drives. My old oil would get less forgiving the hotter it became, so I thought a change would help.
As I said, a change to Penrite Pro Gear has had little difference. I expected more.
Maybe time to look at the clutch.

[bruce]

My 5 speed Nissan box was a bit crunchy when cold 1st to 2nd. Did the oil, no improviement. Then it stopped going into 1st. Bled the slave cylinder which greatly improved the 1st to 2nd cold shift (and helped wih Reverse).