FX4offroad

It runs about 2000 rpm at 75. I'll have to check at 65. Thanks for the info!

Red-Ford

Do you not have a tag on the diff? That would be the way to know 100% without taking the diff cover off.

Ford Fan#1

then yeah I am going to bet it's a 3.73

FX4offroad

I am not sure. I've never noticed it, but will check when I have time.

Fordfan2006

check it at 55 also light throttle should be around 1,500-1,600 if it has 3:73's in overdrive.

Red-Ford

Wont it depend on if he is on stock tires or over sized tires as well though?

greenheadkiller98

yes, that's not a very accurate way to figure it.

Ford Fan#1

his avatar picture looks stock.

Red-Ford

It's just not an accurate way of telling. He may have bald tires so therefore smaller than stock, the PO may have changed the ratio, etc. The only sure fire way that I know to tell gear ration is to count the teeth on the ring and pinion and divide the two. The tag on the diff cover should tell him though, unless gears where changed.

greenheadkiller98

the method i described will give you correct ratio regardless of any modifications, and takes like 10 mins. Idk why people don't use it?