Front differential gearing

I am looking to put 4:10 rear gear ratio in the rear differential of my 99 F150. It is 4x4, and i am not sure what gear ratio needs to go in the front differential. Also, everywhere i look, i can only find gears for the rear. goes anyone know where i can buy a front ring/pinion gear? one further question, what is different about changing out the front gears than the rear gears. Any helpful tips on the subject would be much appreciated.

 

check out randys ring and pinion or diffs only. but you are going to want to run 4:10s in both axles

 

gotta run the same gears in both or it will mess your system up completely

 

4wheelparts has an axle builder.

http://www.4wheelparts.com/AxleBuilder.aspx

 

as others have said you need the same ratio for both diffs.

call wayne at diffsonly.com he has great prices on gears.

 

I was reading somewhere that the differentials may not necessarly be the same size, which would screw with the gear ratios. is that true at all? is replacing the front similar to replacing the rear?

 

some trucks have different size gear housing for front and back. regardless of the housing size you must run the same gear ratio. replacing the front is the same as the rear.