can anyone tell me what the sweet spot is for my 2005 Chevy 3500, Duramax engine, 4X4 Dually Crew Cab, long bed with auto trans and 3.73 gears. I know the sweet spot to run my 2003 Harley is 53 mph for the best fuel economy and all around performance, not saying I run her there but that is the best spot for the bike if'n I want to get the best mileage for my $. I was just wondering if anyone new where the best spot for my truck is in regular mode and also in tow/haul mode, there must be a certain RPM for the best fuel economy empty and towing my 9000# TT. If anyone has this info I would appreciate if they were to pass it on to me so I can be a educated consumer. Thanks
Not sure if this will help and I have SRW's but still have 3.73's. I try to keep my truck under 2000 rpm's. The only time I use the tow/haul mode is when taking off or stopping. If your cruising on the interstate loaded then it doesn't really do anything. The tow/haul mode will keep your rpm's within the best power range of the truck.
The tow haul mode locks up the torque converter full time from my understanding. When towing this helps keep the tranny cool. This is not really needed when empty as the torque converter is locked up most of the time anyway. Keep your RPM at, below or near 2,000rpm for the best milage. I am trying out a set of 35" tires myself to see what the milage is like with the truck.
Mine is a 3/4 ton. The truck seems to get the best milage right at 2200 RPM. This is from empty to a moderate load. Not sure about the tow haul mode. My camper is so big I know the milage is gonna suck so I've never checked while towing it.
