I've got an 86 F250 4 X 4 diesel with a 4 speed and 4:10 gears. I would like to change them to a 3:73 or something close. First of all, where should I buy the gears? Then how much should they be? And how much should it be to get them installed??

By the way...I am running stock tires and wheels, it just sucks that Im getting crappy mileage and can only go about 60 mph on the interstate!!

 

I have the same thing except gas engine. I find 4.10 entirely too much, would want 3.55 instead. But it does increase your towing capacity.

Cannot help more than that, just commiserate.

 

Try http://www.performanceparts.ford.com/home/home.asp, they will have the parts you need. I also agree with the above, drop down to 3.55 gears, it'll be nicer

 

It would be a lot cheaper to buy a set of bigger tires to effectively change your rear gear ratio. The two gear sets with installation should run just under U$1000. Expect to pay half that for some good tires.

Fritz

 

I agree with Fritz; a gear change of .25 or so is pointless. Fractional changes = tires. Changes that can be noticed = .50 or more. This can be especially costly, if they screw up and you have a front or rear differential that whines. Yes, 4X4 gear changes are costly.