Hi All, just a newbie with a tech question about oil in the diff for my 1925 Fordor. Just checked it yesterday, and I couldn't feel a drop with my small finger. I think I read in a Ruckstell book I got with the car, it should be 140 WT. Sound Ok with you?
No! 140 is too heavy for a Ruchstell.
140 is fine for a stock rear end.
I would use 90 in the Ruchstell. Or 75-90.
80-90, anything but straight 140.
The ruckstell book by Glen Chaffin says "one quart of 90 or 140 wt gear oil."
90/140W is just fine, but don't use 600W.
Thanks to all of you for your help, I see Napa has a 80/140W, I can get Monday.