Royal Purple 75w90

[Stang40]

I just picked up an early 90's Mitsubishi Mighty Max with a 5 speed and looking to change the trans fluid. Requires 75w90 GL4. Seems as though I have limited options, and I'm trying to find something locally. RP bottle states that it meets GL4 and GL5 and is safe for yellow metals and synchros. Anyone used it in this application? My other option is Amsoil MTG which is $60 delivered for 3 quarts vs $45 for the RP.

 

[lawman1909]

Never used either, but both are reputable brands. I'm an Amsoil guy so I'd say go with them, but i dont think you'll have a problem with either.

 

[Phishin]

Originally Posted By: lawman1909
Never used either, but both are reputable brands. I'm an Amsoil guy so I'd say go with them, but i dont think you'll have a problem with either.


Remembered from my Mom: Keep mouth shut if you don't have anything nice to say.

You're welcome Lawman1909

 

[GutsyGecko]

Really confused now?

 

[aquariuscsm]

Amsoil MTG

 

[lawman1909]

Thanks..

 

[slug_bug]

Motorcraft® Full Synthetic Manual Transmission Fluid

Gets great reviews on the Miata Forums. Available at local Ford dealer or at Amazon. Unfortunately not any cheaper than your other options.

Runs great in my Miata 6-speed.

 

[Bandito440]

Red Line MT-90 is the way to go.

 

[NHHEMI]

Originally Posted By: Stang40
I just picked up an early 90's Mitsubishi Mighty Max with a 5 speed and looking to change the trans fluid. Requires 75w90 GL4. Seems as though I have limited options, and I'm trying to find something locally. RP bottle states that it meets GL4 and GL5 and is safe for yellow metals and synchros. Anyone used it in this application? My other option is Amsoil MTG which is $60 delivered for 3 quarts vs $45 for the RP.


Haven't used either in your specific application but have used RP MaxGear 75W90 many times and it is a fine product. Try checking out some forums specific to the vehicle. I am sure you will see what works well in it there.

 

[BigCahuna]

I found my local NAPA sells Gl-4 rated gear oil. I checked other chain stores and only found Gl-5 oil.,,

 

[Food Scientist]

I would stay away from oils that claim they can meet both because by definition GL-5 oil has twice the EP additive as GL-4

 

[artificialist]

GL-4 only oils tend to work better in manual transmissions, and in hypoid gears, GL-5 is a requirement.

One nice thing about using RP is that it has limited slip additives already in it, so you don't need to worry if your truck has a limited slip differential or not.

You should use RP in the rear differential, and a different fluid that only meets GL-4.

 

[Stang40]

I ordered 3 quarts of Amsoil MTG and it arrived today...truck is being painted so I'll end up changing the fluid next week sometime, thanks for all the info.

 

[RubentheIowan]

Great choice on the amsoil.