Dropping truck into first gear when towing

Fuddrucker · July 28, 2003

I was very surprised to discover that I had to drop my truck, a 2003 Chevy 2500HD, 6.0, gasser with 4.10 rear all the way down to first gear to get up a 6% grade that was about 4 miles long. I was pulling about 8500lbs and the only way I could keep my speed up was to drop into first gear doing 4500 rpm's and going 35mph. Also when I do that, I start to smell the diff. fluid until things calm down a bit which also concern me.

Anyone out there with the same experience? Seems to me that the truck should have been able to handle that climb a little more easily. If this is the norm, then that puts me at ease. I also may have been babying the truck. When I get up to about 4000 rpm's or so, I start getting worried that I will do damage to the motor. I have heard that you want higher rpm's to generate the power but I am always afraid of blowing the motor. Sorry is that sounds stupid, but I have no idea what the redline rpm is on this engine.

I just added the mods listed in my sig, (K&N, HPPIII, Gibson) so I will have to wait until my next trip out to see if there will be any improvment in power.

Any replies on this subject telling me whether this is normal or not for this type of truck/engine setup would be greatly appreciated!!

Thanks!

Hacksaw Hilliard · July 28, 2003

I think you're alright. The GM engines will rev quite high but that's the way they're designed. I have the 8.1, and mine will rev up to about 4,000 rpms when I'm pulling my 12,000 5th wheel going up a grade. I'm able to maintain at least 45 mph on a 6% grade.

Fuddrucker · July 28, 2003

I think you're alright. The GM engines will rev quite high but that's the way they're designed. I have the 8.1, and mine will rev up to about 4,000 rpms when I'm pulling my 12,000 5th wheel going up a grade. I'm able to maintain at least 45 mph on a 6% grade.

What gear are you in to maintain that speed?

Hacksaw Hilliard · July 28, 2003

I think 2nd gear or third gear. I know it definately not 1st gear.

Hacksaw Hilliard · July 28, 2003

I forgot to add that I have the 5 speed Allison with 3.73's. That will make a big difference.

Shaners · July 28, 2003

I've had my truck taching around 5500 RPM and pushing 70 MPH in 2nd gear when towing with the go peddle almost laying on the floor...

04Chevy2500HD · July 28, 2003

Only place I use 1st gear is on the sand pulling the ATV Trailer loaded around. It wieghs about 7000LBS loaded. I use first gear to keep the RPM's up to keep the truck from digging in(trust it sucks getting it unstuck). But other then that I have never had to use 1st gear with my 6.0L gasser.

-David

als1984z28 · July 28, 2003

How many miles are on your truck? Was it one of the first times that you pulled a load up a hill? I pull an 8500 lb fifth wheel with my 1500HD and the first few times that I towed I could smell something, I figured that it was normal since I was taking it as easy as I could during the recommened 500 mile towing break-in. Since the break in I have been impressed with the pulling power of the 6.0. I pulled the FW from western PA to Michigan on the interstates and could pull almost all the hills in overdrive with no downshifting. The state roads in PA are pretty hilly and have only dropped down to 1st one time and that was because the idiot in front of me stopped in the road to make a right turn. The 6.0 pulls strong as long as you keep the RPMs up dont be afraid to run it.