I'm about to open up the rear end to check for bronze or babbitt thrust washers.
How much 600 Wt. will I need to re-fill when done?
Any favored brands?
Why not 85w-140 from Tractor Supply or your local auto supply?
Here's what I use, one bottle is sufficient quantity. You only want it to just touch your pinky finger when you insert said finger into the oil fill hole while bending said pinky at the first joint.
I like the 85w-140 as Ted says. We used to use it in the final drives on Caterpillar Dozers in a past life. If it's good enough for them, I think it will be fine for a T. JMHO Dave
Tim, that only applies to the early high fill hole, on the later low ones you fill to the hole.
Frank, yep. I'm so used to my "brassies" I overlooked that aspect, but I think Bill only has early cars too. This at least gets the info out to the later car owners.
The generally accepted major overhaul point for T rear ends "back in the day" probably averaged about 12,000 miles.
I think, that with modern 80w90 or 85w140 and some way to drain the oil from the rear end, you could probably at least double that.
For 10 bucks Northern Tool has a neat little oil suction thing that works great drawing out the rear end oil.