I have a 2001 Ford Ranger 100,000 miles. I have had to change the computer module at 60,000 miles as it quit working.

But now, when in reverse in 4x4, it seems like the emergency brake is on. Yesterday, in 4x4 on slick streets, it sort of locked and lunged... Anyone else ever see this?

Thanks,
Sorry, no, it was an icy road... packed snow..
Also, it doesn't do it in 2x4 when backing or it never jumps or bucks like it did.

why are u in 4WD on a sealed road? u'll wreck your diffs and shafts, perhaps o'heat ur motor. Think about what ur doing, & learn how to drive it!

you should check your front diffrention it might be lock up or it might not have oil and check your read end too good luck

Are you the original owner of the truck? Reason for asking is the rear might have a locker in it or as I experienced in my 02 the pin was well past the specifications for allowable play and causing troubles in there. This will also happen if the front is locked on slick roads the locking ang lunging part, I am assuming that you was in 4hi and not 4 low correct.