Staying in 9th gear when heavy

Try to put it back in 10th when you hit top of hill, you wont be getting a fuel bonus running in 9th? (you wont be getting any good wright/ups from CO. try to find the power band of eng. in this truck can be under 1800RPM if its running into RPM. gov. at 1800RPM the fuel is being turned off by comp. CK. if fuel filter has been changed, if it has see/thru type and fuel is near top of it you have a plugged up fuel filter, if you have the type that you cant see thru just get it changed at T/stop an see if she runs better good luck an try to keep it in the highest gear poss.

 

Ummmm....yes...gear down if your falling on your face pulling a hill.....but remember to gear up again.....

 

First you have to know your engine. Like a cummins ISX for example peak torque is at 1200 rpm. That's when the engine is most efficient in relation to power. If you look at a power curve on a chart it looks like a hill. peak torque is at the top of the hill. Go past it and you start going down the other side. About 1800 rpms you are about 1/2 way down the other side. No sense in that. Get your rpms back over below 1600.

If you have a small 300 hp Mack with an 8 speed, then you will wind her out. Not the big motors. Do a little research on your engine and how it's designed. Find it's peak torque. it should be 12-1400 somewhere.

 

I just seen you have a Maxxforce. I never drove one of them but they are puppy dog motors. If you have the DT model 300 HP, then peak torque on it looks like 2000 rpms. I can't see the chart good so I might be mistaken. If that's the case then you are okay. I'm use to 450-500 HP.

http://ca.internationaltrucks.com/trucks/engines/maxxforcedt

 

Here's the chart. It starts low and like you said flattens out. I can't read them numbers without finding my glasses.