When to use tow/haul mode?
 

2009 Express Cargo with 6.0 engine. 25k miles on van.

Going to be towing two motorcycles next week and I've never used the tow/haul mode in a vehicle before. My truck doesn't have it.

Trailer is 1200 lbs empty and each bike is mid 400's.

Let's say 2000 lbs total trailer weight.

Should I use tow/haul? I'm rated to tow 8000+ on the 3.73 diff.

Mostly flat freeway driving.

thanks,

Will

Your van won't even know its there.
My 2002 express has the vortec 350 and the 373 gears. I also have the towing package. Its awesome pulling my boat.
Tow haul just delays the shift points and so on. Still use your common sense, like dropping it to 3rd when going up a long varied stretch so its no hunting in and out of OD.

Ok cool. I kind of thought the big girl wouldn't be too impressed with that load but wanted to make sure.

I checked out the operation of the tow/haul mode and found that it locked the transmission into shifting at rpm points. The transmission would upshift when the rpm reached about 2100 rpm and would downshift when the rpm was reduced to about 1700 rpm. This would put it into 6th gear at about 65 mph for my van. Thus if I was towing at about 62 mph it would never go into the top overdrive gear. So my advice, for best gas mileage, is to leave the transmission in normal mode and use the tow/haul feature only when the transmission seems to be hunting for the correct gearing excessively. Maybe when driving through hill country. But you could also use the manual shifting feature to select the correct gear for long uphill or downhill sections.

Outside of helping the transmission avoid hunting for a gear ratio, I do like the feature that when tow/haul is on and you are going down a long hill it will downshift to help reduce the need for using / heating up the brakes too much.

Thanks for all the info. Most of the trip is pretty flat but eventually I'll be in North Carolina and have some hills. I'll pop it into tow mode then but if I can keep it in normal mode most of the trip I suspect I'll get better MGP.

I get about 17 with it so any help is appreciated : - )

I'm back. Van noticed the bikes/trailer were back there but didn't care much. I ended up with 13.8 mpg average for the entire 1000 mile trip. She liked to downshift and rev up to 3500 on those hills in TN and Kentucky. : - )