i have a 87 f-150 4x4 . its got the 302 and about 200 thousand and runs perfect. the tranny shifts a bit hard now and then but for the milage i cant complain. but my question is about the 4 wheel drive. it works fine but when turning on the streets or backing out of spaces in 4 wheel the truck kinda jumps. it almost feels like the tires are flat and its kinda hoppin. is this normal? i've had the truck 3 years and havent used the 4wheel much. also how fast can you go in 4 hi and low?