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steved0x · 06-04-2014, 07:38 PM

The redline application guide says this car should use their MT-90, which is a GL-4. I think Mobile Delvac is a GL-5. I use the delvac in the diffs for my tacomas (well I sold one so the one that is left

) and in my FJ cruiser. I use the MT90 in the 5 speed in the Tacoma, and also my son's Miata transmission, which hates GL5.

It could very well be the fluid, and there are not many GL4 out there. I think Brad Penn makes one:
http://www.summitracing.com/search/product-line/brad-penn-multipurpose-classic-gl-4-gear-oil

And redline makes a couple of GL4s, the MT90 is the one I use on my vehicles that call for a GL4:
Red Line Synthetic Oil - Gear Oil for Manual Transmissions - MT-90 75W90 GL-4 Gear Oil

Edit: I may be way off, I was putting in 1988 Porsche 944 Turbo into the redline application guide for the above. I just saw in your sig that yours in a 1989, so I put that into the redline application guide and this is what it recommended for the transaxle: 75W90 GL5
http://www.redlineoil.com/product.aspx?product=58304

Sounds like that is about the same as the Mobile Delvac 75W90. Good luck, hopefully a fluid change will help.

Steve

06-04-2014, 07:38 PM	#8
steved0x Registered User Join Date: Dec 2012 Location: FL Posts: 4,144	The redline application guide says this car should use their MT-90, which is a GL-4. I think Mobile Delvac is a GL-5. I use the delvac in the diffs for my tacomas (well I sold one so the one that is left ) and in my FJ cruiser. I use the MT90 in the 5 speed in the Tacoma, and also my son's Miata transmission, which hates GL5. It could very well be the fluid, and there are not many GL4 out there. I think Brad Penn makes one: http://www.summitracing.com/search/product-line/brad-penn-multipurpose-classic-gl-4-gear-oil And redline makes a couple of GL4s, the MT90 is the one I use on my vehicles that call for a GL4: Red Line Synthetic Oil - Gear Oil for Manual Transmissions - MT-90 75W90 GL-4 Gear Oil Edit: I may be way off, I was putting in 1988 Porsche 944 Turbo into the redline application guide for the above. I just saw in your sig that yours in a 1989, so I put that into the redline application guide and this is what it recommended for the transaxle: 75W90 GL5 http://www.redlineoil.com/product.aspx?product=58304 Sounds like that is about the same as the Mobile Delvac 75W90. Good luck, hopefully a fluid change will help. Steve Last edited by steved0x; 06-04-2014 at 07:41 PM.