i was curious if you can put 3.50 gears in the rear diff and 3.55's in the front without causing too much stress on the drivetrain. i use 4wheel drive in my truck when i go four wheelin as well as going over the pass in the snow etc. so it will be used on the highway some.
thanks

86 f150 , 9 inch rear, dana 44 front

 

Sure, I think they need be with 1 to 2%. You don't need 4wd on dry pavement, so take it out when not needed to prevent bind. Tires at different air pressure, worn treads, etc. vary overall ratio also.