i got a 93 f150 4.9l 5spd 4x4 with 3.08 open diff.
just wondering, can i put just one locker in the rear diff. and still use 4x4 with no problem?

i can see it working cause they are the same gear ratio just that the rear both tires would spin.

 

Yeah sure that works just fine, most of these trucks only get an LS diff in the rear if they get one at all. If your tires are larger then stock now would also be the time to improve the gear ratio.

 

i do have 31 in tires. im thinking about doing 3.55 ls diff's in both front and rear. but when i go to junk yard they have axels already out of trucks and i see a f250 3.55 ls but the diff. housing looks bigger than an f150. if i can just do gears that would be even better. but if i have to swap axels then that would be expensive. i would do rear axel myself but front i would take in cause of alignmen i would need and everything else. the way im looking at it is that a locker would be in my budget right now. are f150 and f250 diff. housings a different size?

 

Yes the F250 uses a Ford 10.25 versus the Ford 8.8 in the F150, the axle would bult up under your truck but the hubs are 8 bolt so you would have mismatched wheels. 3.55 was very common in V8 f150, you should not have much problem finding that. If you do find a 4x4 F150 with 3.55's you could simply transfer the front center section to your truck, it's not necessary to replace the whole front axle.