265 OD transmission - best lubricant?

Gary Knox

Gary Knox

E9 Member Emeritus
Site Donor $$
Messages
1,821
Reaction score
746
Location
West Chester, Pennsylvania
I purchased a '74 CS last month that had the body, interior, and drive train refurbished in 1993. <25K miles on it since then, but I want to change the fluids in the 5 speed OD transmission and differential. Synchros seem good now, but I want to keep them that way!

I found the 5 speed transmission in my Porsche 928's shifted better with good synthetic lubricant (they have a transaxle with same lube for diff and trans, and tend to have a balky synchro when going into second gear). Looking for advice on the best lubricants for not only the transmission, but the differential as well (non LS).

THANKS for your experience/opinions.
 
Carl Nelson recommends a combination of 1 quart of Redline MTL and 0.7quart of 80/90wt mineral oil.

http://bmw30cs.blogspot.com/p/5-speed-conversion.html

Gary Knox said:
I purchased a '74 CS last month that had the body, interior, and drive train refurbished in 1993. <25K miles on it since then, but I want to change the fluids in the 5 speed OD transmission and differential. Synchros seem good now, but I want to keep them that way!

I found the 5 speed transmission in my Porsche 928's shifted better with good synthetic lubricant (they have a transaxle with same lube for diff and trans, and tend to have a balky synchro when going into second gear). Looking for advice on the best lubricants for not only the transmission, but the differential as well (non LS).

THANKS for your experience/opinions.
Click to expand...
 
charofire,

Thank you very much for that information. Now - finding the mineral oil!!

By the way, is that the best lubricant for the differential as well??

Thanks again,
 
HB Chris said:
I used regular GL-5 gear oil. Hypoid is for differentials I believe.
Click to expand...


Beg to differ with you HBChris, but if your transmission has brass or "yellow metal" synchros, GL-5 is probably not what you want to use. Generally speaking, GL-5's tell -tale smell is a sulfur based additive used for extreme pressure situations found with differential spiral gears - where shock loading occurs. These extreme pressure additives evidently have a corrosive effect on yellow metals. I have "heard" that more modern GL-5 lubes are kinder toward yellow metal but I haven't been able to confirm this.

http://www.e9coupe.com/forum/showthread.php?t=4518
http://www.e9coupe.com/forum/showpost.php?p=34933&postcount=2
 
You must log in or register to reply here.
Back
Top