A couple of weeks ago I hauled an old truck to the junk yard along with filling the bed with scrap cast iron. The last mile to the junk yard is up a really steep grade that I guess is between 15 and 20%. The truck hauled the load fine till the grade but then on the grade it wouldnt accelerate in 3rd gear at 2200 RPM. It didnt slow down either just maintained. I know the rule of thumb is if the motor wont rev it is being lugged according to cummins but I feel that I was in the right gear for the slow speed. What do you guys think?

 

Lugging the Cummins is not 2200 rpm. You were just pulling hard. Lugging comes in at much lower rpms, 1000 to 1200 rpm and trying to accelerate in 4th gear with a load. She starts buckin' thats luggin'............JIM

 

As long as you aren't losing RPM you are OK. And like Jim said, 2200 RPM on a Cummins is plenty of RPM. Don't let it get dragged below 1500 and you won't hurt it.

 

If you wanted to accelerate, just downshift. The good 'ol Cummins can handle 3000rpms for quite some time if needed

 

Thanks guys. That was the first time I have managed to get that responce from the motor. Even when I pulled my 95 back from texas the next week I never had a loss of power to accelerate. That was about 15,000 LB combined for 1200 miles. These are my first 2 diesels that I have owned and I want to treat them right. Been wanting a cummins for 10 years till 2004 when I finally got one. I worry about treating them like gas rigs and do my best to remember not to short shift them. I know that the cummins will take 3K RPM all day long but I really dont like running up that far. I try to keep it between 1600 and 2000 RPM empty and a few more revs when loaded. I drive diesels at work all the time but they are abused. No warm up before they are hammered on and they tend to idle alot to run the hydraulic pump for the bucket (I work power lines part of the week) and the flat bed is treated like an indy car. The line truck is always lugged. Even running the 2 spd rear she hates the gear shift because it defuels at 2200 RPM