Wilbur01

I have an 02 with a 6speed and I am always wonder what is the best RPM range to tow in. My trailer is around 13,000lbs loaded. I find that at about 63mph I am at 2400 in 5th and 1850 in 6th. I thought I read about not towing under 2000 RPM’s because it is easier on the truck. I have always had Auto’s before this 6speed.

stock03

Keep in mind that higher RPM will help with EGT's.

Homestead

RPM's are your friend. I tow about the same as yourself and do most of it in 6th, just don't lug it even a bit. If it seems or feels right, downshift and carry some revs in 5th, it won't hurt. Your EGTs will be a little lower and the truck will just pull better.

I have a temp gage in my trans and have noticed that even though I can pull a hill in 6th gear, the trans runs cooler in 5th and will come down in temp when pulling a long grade in 5th as to using 6th.

Just use some common sense and drive it and don't be afraid to work it.

Jeff

hamilton71801

I tow by the EGT gauge and try to keep it under 1200* no matter what gear I'm in.

nkennedy

X2 on the not lugging it. It causes EGTs to soar. I have an 01.5 6 speed, and get the same RPMs. I pull at 62 MPH and around 1800 RPMs in 6th in the flat land. In the hill country I run in fifth around 60 with a little higher RPMs.

dieselengineer

With nv5600, 19.5 (265) in 5th is about the same as 6th, 4.11 and EOM tire and wheels. Nice setup, runs around 2200rpm, EGT are good, and tranny temps are okay and stay below 180*. Towing in 6th really makes the tranny temp go up. 5th is a stronger gear and the larger wheels makes the gearing about right. Without the trailer, 6th is a nice highway gear. Best of both worlds.

58fordf100

Cummins says on their website the "sweetspot" on an ISB is 2150 RPM. They also say to never cruise below 1900 RPM.

Fifth is definatly better than sixth. Fifth is the most efficiant gear in the transmission. That is why all of ours run cooler in 5th than in 6th. Also you will get better MPG by towing in 5th.

CoastalDav

I assume you have a 3:55 rear. My combination was a 2000 Dodge Cummins with the NV5600 towing the trailer in my signature for 200,000 miles.

The reply above this one indicating 5th as being a better gear is correct. You may have to slow down just a little to get rid of some of the engine noise. I would tow at 64mph in 6th just to keep it down. Mileage would suffer. 10mpg.

When running 55 to 60 I would always use 5th. It would result in mileage greater than 13.

As mentioned above, 2150-2200 rpm's is were you want to be at 65 in 6th. To that end a 4:10 or a 4:30 gear is necessary. If towing all the time, it would be worth the money. Otherwise I'd slow down a little and keep the 3:55's for running lite to get the mileage.

I intend to install at least 4:10's in my 06 which will give me 2000 rpm's at 65 for towing. 4:30's if I can find them. (2200 at 65) I will be towing all the time.

Dave

Wilbur01

Looking on the cummins web site it does look it sweet spot is right at 2150Rpm. This is fun link to play with http://www.powerspec.cummins.com/sit...ng/gearing.htm

CoastalDav

Just to keep things correct, I indicated I had towed 200K miles with the trailer in my signature.

That was incorrect. It was suppose to read, I had driven the truck for 200,000 miles and towed etc, etc......

Did not want to mislead anyone.

Dave