gear ratio of my axle?

[teddyyyy]

on my 72 2WD F250, I tried to find the gear ratio (cuz my speedometer doesn't work, and I have just installed a very precise digital tachometer, I could calculate the speed once I know the rpm and gear ratio, and wheel size).

I crawled under, and saw some big stamped numbers "C32055" on the rear axle housing. the factory manual part 15-01-14 says "C3.." means "Dana single speed locking axle", model 60 or 70. wikipedia shows that Dana 60 actually has a very wide range of gear ratios.

the manual also says that the metal tag bolted to the axle housing should say the gear ratio etc. but the tag on my axle only says "use only ...... lube ", no numbers.


so how do you know your real axle ratio? does your metal tag mention the gear ratio?



---- btw, my axle has quite a lot of gunk build up around the housing gasket, and around the filler plug. I could change to a new gasket, but what about the plug ? if that leaks, any way to seal it?

[ultraranger]

Check the axle code on the drivers door.

[Mach428]

The rear could have been changed over the years and not be the same one as indicated on the driver's door.

If you want to check the current ratio, jack up the rear; mark the tire with a piece of chalk, mark the drive shaft with a piece of chalk; have someone slowly rotate the tire 360 degrees while you are underneath counting the number of drive shaft revolutions. The number of shaft revs to one tire rev will give you the gear ratio