RPM, Downhill, Exhaust Brake

[RVblaster]

My Dodge Ram 3500/6.7 Cummins will sometimes rev up to ~2500 RPM coming downhill with the tow/haul engaged and the exhaust brake on. Going up hill at 65MPH, unless I deliberately kick it into a lower gear, it would normally run at 16-1700 RPM. If I tap the brakes a couple of times it will usually downshift and drop the RPMs. I believe that is transmission programming and not the exhaust brake. I will say, that if you feel a need to run the exhaust brake, then 65 MPH could be a bit fast on a long downhill stretch. The best way to protect your brakes with a heavy load is to slow down - for all the reasons that trucks often have a lower speed limit on long downhill grades.

[svoshop]

Originally Posted by RVblaster

My Dodge Ram 3500/6.7 Cummins will sometimes rev up to ~2500 RPM coming downhill with the tow/haul engaged and the exhaust brake on. Going up hill at 65MPH, unless I deliberately kick it into a lower gear, it would normally run at 16-1700 RPM. If I tap the brakes a couple of times it will usually downshift and drop the RPMs. I believe that is transmission programming and not the exhaust brake. I will say, that if you feel a need to run the exhaust brake, then 65 MPH could be a bit fast on a long downhill stretch. The best way to protect your brakes with a heavy load is to slow down - for all the reasons that trucks often have a lower speed limit on long downhill grades.

You have a 68RFE or Aisin Trans. So programming would be very different than the Allison 3000 that the Seneca has. But I appreciate the reassurance with respect to the engines RPM 👍🏼

[miles ahead]

i found the exhaust brake switch, now I just need to try it out next time I decend a big hill.

[gorgas99]

I see earlier in the exhaust brake conversation that the E-Brake will turn on the brake lights (that makes sense).

If the brake lights are on when E-Braking, will that also activate my trailer brake controller (or the brakes on my towed) ?

I always thought that I should NOT use my E-Brake when towing since that will NOT engage the brake controller and therefore the brakes on the trailer won’t engage. Sounds like that might not be correct...

Does anyone have a definitive answer ?

I’m towing 6,500 LBS (trailer + car) in most cases.

Thanks !

[Oma/opa]

The brake lights do NOT turn on on my 2017 37TS when the exhaust brake engages

[RVermont]

Originally Posted by gorgas99

I see earlier in the exhaust brake conversation that the E-Brake will turn on the brake lights (that makes sense).

If the brake lights are on when E-Braking, will that also activate my trailer brake controller (or the brakes on my towed) ?

I always thought that I should NOT use my E-Brake when towing since that will NOT engage the brake controller and therefore the brakes on the trailer won’t engage. Sounds like that might not be correct...

Does anyone have a definitive answer ?

I’m towing 6,500 LBS (trailer + car) in most cases.

Thanks !

The Seneca uses a 7 pin connection which uses a separate wire for the brake controls than the brake lights. I pulled up a drawing and the brake control circuit appears to be on the 2 position and is usually a blue wire. This receives a signal from the controller.

So unless the controller is incorrectly wired the unit should not respond to the brake lights.

[Rustynuts]

Originally Posted by Oma/opa

The brake lights do NOT turn on on my 2017 37TS when the exhaust brake engages

They do on our 2018.5 37RB....

[staineous]

Originally Posted by gorgas99

I see earlier in the exhaust brake conversation that the E-Brake will turn on the brake lights (that makes sense).

If the brake lights are on when E-Braking, will that also activate my trailer brake controller (or the brakes on my towed) ?

I always thought that I should NOT use my E-Brake when towing since that will NOT engage the brake controller and therefore the brakes on the trailer won’t engage. Sounds like that might not be correct...

Does anyone have a definitive answer ?

I’m towing 6,500 LBS (trailer + car) in most cases.

Thanks !

Most, if not all, trailer brake controllers and TOAD brake controllers use accelerometers to determine how much brake to apply. So, in that case the trailer brakes will be activated when the brake controller senses that the vehicle is slowing when the exhaust brake is applied.

Then exhaust brake is a great way to slow your rig when you are towing. It will save a tremendous amount of heat and wear on your brakes.

[johnboye]

It does make a big difference. You will love it.

[PatrickBenshoof]

When exhaust brake is activated is there a way to control how much exhaust brake is used? Is it progressive or do you just use the gas pedal to control how much it slows you down. I find sometimes is slows me down too much.