So i used the calculator tool in tech articles, 3150rpm at 60mph in 3rd gear,26''tall tire, with a 700r4. Came out with 4.10xx, is this right?

More like 5.8 if your 700R4 was in O/D. Is your tach accurate?

3150 rpm in 3rd gear. as far as i know it's accurate.

It's unlikely you'll be doing 60 mph in third gear with a 700R4. Since third gear is 1:1, it will be the same as third gear with a TH350 or TH400.

OD in the 700R4 is 0.70

Too deep a gear in the diff with a 700R4 can easily smoke the tires off the line with too much torque multiplication. A better ratio is 3.73.

Well, my OD isnt engaging. so im stuck cruzing in third gear . i was trying to find out my rear gear ratio without taking off my diff. cover. Cuase 3150 rpm at 60mph seemed to high for the stock 2.73's. Any ideas on how to trobleshoot on my dead OD?

any ideas on the over drive?

No but if you want to know exactly what gears are in the diff, pull the cover and count the teeth.

Yeah thats probably what ill end up doing. Going to have to wait until it starts warming up a bit, as its still below freezing in my garage. i know my overdrive isnt engaging, anyways to tell what wrong?