Had my 2004 Ram 1500 5.7H for two years now. It has ~115k miles on it and I recently purchased a 4800lb UVW toy hauler. Going over the Cajon Pass Saturday was no problem but the down shift brought the engine up to 4500 to 5000 RMP. If I let it go down to 4K it would up shift and bog.

Is 4500 to 5000 RPM while towing up hill too high for this motor in the long run? Sure was a lot of HP at that range.

 

sounds normal to me

 

With a heavy load you dont want it going into to OD. You will burn up the clutches

 

OK thanks. Just not used to winding out a truck engine.

 

I think peak torque is at 4400 rpm iirc btw.

 

That is normal for the 5.7L HEMI. It does not reach peak horsepower until 5,400 r.p.m. The motor is gutless, while pulling a travel trailer, below 3,500 r.p.m.

When I am going up the Cajon Pass, Grapevine, or any other 6-plus percent grade, with my 5,000 pound travel trailer, I am always manually locked in to second gear winding her up around 4,500 to 5,000 r.p.m. to maintain 60 to 65 m.p.h. That is the name of the game with the HEMI.

On a "live chat" with the HEMI engineers, I asked them is it damaging to run the motor this fast for long periods of time. They said; RUN IT! The HEMI was designed to hold up to this kind of use.

 

Awesome! It really did run great going up the grade, 70mph easy.

 

Yeah, 6% grades (or steeper) do not phase my truck while towing my trailer. I just shift (automatic transmission) into second gear and can run 60-65 m.p.h. without the HEMI breaking a sweat. There is even enough left still to shoot up to 75-80 m.p.h. for passing big-rigs or other pickups pulling trailers.

For peace of mind, just make sure that you use a high quality, motor oil and oil & air filter. Change it according to the owner's manual.

For me, I use only Mobil 1 synthetic oil and WIX filters. I change the oil every 5,000 miles or six-months. Whatever comes first. Good luck!

 

It's probably been asked somewhere else but is it OK to switch to Mobil 1 synthetic at 115k miles? I don't know what the original owner used. I use Valvoline 5w-30w.

 

As long as you do not have a problem with oil consumption, you should be fine. Mobil 1 makes a 10W-30 for High Mileage engines if you find that your engine is using up a bit. Unless you live/operate your truck where the temperature is 32 degrees F. or lower, the difference between 5W-30 and 10W-30 is negligible.