Jim---This could lead to as many different answers as to the kind of
"fluid" used in engines, carburetor dashpots, brakes, etc., so I'll
start it off. I have used nothing but 80W-90 oil in my transmission
since I began doing my on work. When this '73 was still under factory
warranty, I would assume the dealer would have topped it up with what is
recommended by the owners handbook, that being their favorite brand of
either 80W or 90W gear oil. For many years I had used nothing but the
Valvoline label here. About three years ago I was unable to find this
and had to use the more modern Sta-Lube 80W-90 with GL-5 additive.
There's about 290,000 miles on this transmission, with nothing changed
but the lubricant. This is done about every 50,000 miles or sooner,
depending on clutch changes. If the GL-5 is going to do some harm, it
hasn't done so in nearly 35,000 miles. At this point of the transmission
life, I'm not sure any failure could be blamed on anything but the high
mileage. So far, there's been no sign of metallic shavings in the
replaced oil( but I have never had it analysed.) Nor has the magnetic
drain plug come up with anything significant.
This is a non-OD gear box. It is obviously very stout.
Dick T.
CF11143
|