My old Discovery has a "centre diff lock" that locks up the transfer case diff - otherwise its permanent 4WD, it only binds up like yours when that is locked. Same issues in a Suzuki Samurai, Subaru Leone/DL, Suzuki XL7 - anything that locks front/rear drive together.

It's due to the front and rear driveshafts turning at the same speed, even though the front needs to go faster. The hops come from the driveline forces building up and overcoming the tyre/ground forces, relieving the pressure in a "hop", then building up again. Much like earthquakes from a faultline.

>>> cdenk@alltel.net 26 Jan 08 12:30:41 >>>
The 1996 Bronco with manual hubs and transfer case (part time), 
<snip>
On tight corners on dry, locked up, slow speed, sometimes can feel tires slipping, kind of like a 
hop, probably part due to the non-constant velocity cross/yoke U-joints. 
<snip>


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