[Fulltiming]

The de-rated torque on the C-15's mated nicely to the Allison. No question, the Allison's were much smoother shifting than the ZF's and according to John Clark the Allison's were faster 0-60 mph than the higher torque C-15 with the ZF 10 or 12 speed transmission but the Allison couldn't keep up with the ZF's in the mountains.