700R4 speedometer gear selection
According to the calculator at Bowtie I should have a 17/39 combinations with my 3.08 rear and 255/60R15.
In other words, I only have to swap the 18 drive gear with a 17teeth.
But how does this work? Are there offset sleeves?
Another question: The yoke from my TH350 has some pretty bad wear and corrosion pits. I can sand/polish it in a lathe. Is this a good idea? How much can I reduce the diameter before I will have a leak? (It was leaking in the TH350)
Regarding the speedometer gears, I still haven't found out which combinations can be used in the 30 series carrier vs. the 40 series carrier. I will certainly send you an email when I find an answer.
Yoke:
Maybe after you have the drive shaft shortened, the yoke will be in a slightly different position which will allow the new seal to ride on a fresh surface. If so, you shouldn't have a problem. If not. . .
My calculations show that for a 255/60R15 with a 3.08 rear you can use a 15T/35T, 16T/38T, or 17T/40T combination.






