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View Full Version : Is Penrite Pro Gear 75W-85 GL4Plus Ok for the FS5R50B?



NADSyourUncle
24th June 2025, 01:16 AM
As the title suggests, I am looking to confirm whether the Penrite Pro Gear 75W-85 GL4 Plus is suitable for my Patrol's FS5R50B transmission?

I bought this stuff a few weeks ago and its finally time to put it in, and I was browsing SCA for other stuff and double checked its specs, noticed its **GL4 Plus**.
I know not to use GL5, and I know it says compatible where GL4 is recommended, but hoping to hear from the masses.

This transmission was freshly rebuilt, so I want the best oil for it.

Link to the product below for ease of reference. https://www.supercheapauto.com.au/p/penrite-penrite-pro-gear-oil---75w-85-2.5-litre/342312.html?cgid=SCA01070502

And if anyone knows, is it also ok for the tranfer case? Looking to avoid ATF based on (1) I'm going outback and value reliability over fuel economy; and (2), my transmission specialist said to go for gear oil over ATF. Otherwise I'll stick with the Nulon 75W-80 i already have.

Touses
24th June 2025, 09:19 AM
Hi NADS,

You're spot on re GL5. Anecdotaly I had been made to believe GL4 is also a no no.
I dumped the GL5 from mine replaced with the 4 and the difference was immediate.
Swap your 4 plus for the lighter oil.

Cheers

mudnut
24th June 2025, 11:55 AM
As the title suggests, I am looking to confirm whether the Penrite Pro Gear 75W-85 GL4 Plus is suitable for my Patrol's FS5R50B transmission?

I bought this stuff a few weeks ago and its finally time to put it in, and I was browsing SCA for other stuff and double checked its specs, noticed its **GL4 Plus**.
I know not to use GL5, and I know it says compatible where GL4 is recommended, but hoping to hear from the masses.

This transmission was freshly rebuilt, so I want the best oil for it.

Link to the product below for ease of reference. https://www.supercheapauto.com.au/p/penrite-penrite-pro-gear-oil---75w-85-2.5-litre/342312.html?cgid=SCA01070502

And if anyone knows, is it also ok for the tranfer case? Looking to avoid ATF based on (1) I'm going outback and value reliability over fuel economy; and (2), my transmission specialist said to go for gear oil over ATF. Otherwise I'll stick with the Nulon 75W-80 i already have.

It depends on which year Patrol you own. Early models required Gearbox oil, but they switched to ATF. I was led to believe the reason for doing so was that when the oil was cold, it could have a slight hydraulic drive effect on the transfer case. This caused the front drive shaft to turn and cause weird noises while driving. And yes. GL5 causes the brass components to wear faster and the gears to grab when cold. A mechanic used GL 5 in my Patrol. I had to double shift between gears until the oil warmed up. Dumped that oil and used Castrol GL4 and the problem went away. I have shied away from using the GL4 Plus, as it is may have unknown effects on the gearbox.