Just purchased a 1994 F250 diesel with a five speed standard transmission. I was wondering how I could find out what the rear axle gear ratio is? Usually, there is a tag that is bolted on to the rear end cover. However, getting kind of decrepit in my old age and would have a hard time crawling underneath the truck. How about something in the VIN number?
I have the 235 x 16 tires and at 60 mile-per-hour the RPMs are 1800. I had another truck years ago and the same mile-per-hour and RPMs are the same and the actual ratio was a 3.55. If my axle ratio is a 3.55 do they make a 3.23.

 

If I remember right, it should have something on the door sticker to identify the axle...

I can tell you it's either 3.55 or 4.10 gears... What are your RPMs at about 70? Mine has 4.10s and runs 2250 ish at 70

 

there is a axle code on the door tag. then look in the owners manual and there is a chart in there.

 

Thank you both for the good posts. I was out driving today and paid particular attention to speed/rpm. Looks like at 70 miles an hour it is about 2200 RPMs. Without doing any more research at the moment it appears that I probably have a 4.10. I did some calculations and I think if I had a 3.55 the RPMs at 70 mph would be 1900. I think the truck has enough torque to handle that. Just thinking... Where can I find a complete rear with 3.55s. Thanking everyone in advance.