Agree on all the above. I use cruise while towing all the time.
My Duramax rarely downshifts unless I'm in the hills.
Gas vehicles are a little different. My Yukon, I'll tow with the cruise but if it starts downshifting out of overdrive, I'll lock out the o/d and still use cruise. Engine RPM's run a little higher, lose a little MPG but it's better than losing a transmission. Owners manual will say the same.
Agree that gas vehicles are different. Also, even with my diesel I don't use cruise control if it's raining hard or snow/ice conditions
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2018 327CKTS
2012 F350 Lariat 6.7 4x4 CC SRW
I use my cruise control towing our FW. I set it at 65 MPH and cruise unless bad weather or heavy traffic. I find overall my fuel mileage is better as I'm inconsistent with my foot as the controller. The only thing I have to watch is the turbo boost when climbing a hill. It will climb to high trying to maintain speed. I usually drop out of cruise control for long climbs.
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ETCrockett
2016 Jayco Pinnacle 38FLSA
2009 Ford F450 DRW
RVing all my life......1st Jayco
No problems with cruise control here. We keep it between 65 and 70 to try to save on gas. Up hill we take it off and go easy on the tow. Otherwise if level cruise control all the way.