Planning a trip to New Mexico (from Quebec) at the end of summer. I read a few posts on why it would not advisable to tow with a Cummins 5.9 with the Allison 542, in the mountains. Being ready to compromise on speed going up or downhill, can it be done reasonably safely from a mechanical point of view? I have a Breakaway with Cummins 5.9 (190HP) and Banks ‘230HP’, towing a VW Golf TDI 2800lb. I installed a gauge to be able to monitor the transmission’s temperature closely. Would I be able to control engine and transmission temperatures within safe limits? And the real question is: Is the temperatures a good indication to control the amount of stress imposed to the mechanics?

Uphill, be prepared to spend a lot of time in 2nd and 3rd gear and you should make it. I hated the 542 and love the 2000 I replaced it with. But before the advent of th 3000 it was the only automatic short enough to be used.

Downhill, just drop it a gear and you will be ok.

You will make it.

Towed both a Saturn and a Honda Fit cross country with a 5.9. Downshift and you'll be fine.