You may need to take it to a different tire shop and tell them you have a balance problem. Have them balance the tires and record what they find. Also looking for bad tires (broken belts). If they find a problem and fix it, good. Take the bill back to the other shop and ask them to pay for it. May or may not work, but your Jeep will be fixed.
As for the tire skidding, it could be stuck in 4x4. Have them check to see if is stuck in 4x4 when it is on the rack. Of the four 4x4 I have they all do this to a point, in 4x4 you will really know it.

It's not the 235 tire size. They could also have the alignment wrong.
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2006 Jeep Liberty CRD
1998 Beetle TDI
Malone Tuning Stage 22001 Dodge Cummins
2005 Dodge Cummins
ASE, OBDII / VAG-CAN scaner / Service Manual
