View Full Version : Rear differential oil

07-12-2005, 09:44 PM
It is time to change the oil in my rear axle on my 1951 Commander. Last time I did it, I used straight 90 weight gear oil with no additives. Now, I go to the same store where I bought it the last time, and they don't have anything like that anymore! What they do have is 85-90 weight multi-vis with additives, 90-140 weight with additives, and some synthetic called "Mystic" that is rated as 85-110 multi-vis with a whole bunch of additives. I can keep looking, but what is the general consensus on rear axle oil? It is a type 23 4:55, the stock axle, and has never had anything but straight 90 weight dino squeezin's.

07-12-2005, 10:07 PM
90 wt (75W90 or 75W140) with additives not an issue in rear diff., issues have always been raised about other than GL-1 in OD trannys.

07-14-2005, 02:00 PM
Where does one get GL-1 oil?

07-15-2005, 06:50 PM
Most auto parts stores only sell GL-1 in 5 gallon pails, but TRACTOR SUPPLY sells it in gallons and AMSOIL sells it in quarts (http://www.oldcarfart.com)