Ex03AK

I bought my truck about 2 years ago and it ha a Jake Brake (the real thing made by Jacobs) with the Cummins name on it. It seems to work correctly though I'm not sure I'm using it correctly. It only engages above 35 mph and when you give it gas at any speed it disengages.

My question is when I'm towing my 10k travel trailer, do I leave the pull switch on the gear shifter engaged all the time or do I engage it only when I think i need it?

Thanks,
Stew

Danavilla

I converted mine to a dash switch but rarely turn it off even when not towing. Exceptions should be when on icy or slick roads but, for me, those are rare occasions. Our '06 models have a very sophisticated control system that does virtually everything for you but shift down for you on downhill grades and it will even do that if the cruise is set.

Hector-BD

If you leave it on all the time it will save your service brakes all that much more. The down side is your always slowing down.

Danavilla

"The down side is your always slowing down." Only if you take your foot completely off the throttle. Use your foot to barely crack it open and you'll coast like the brake is off. Foot off and the brake takes over, slowing you down to about 45 mph, disengaging and downshifting, then reapplying the brake down to about 20 mph in my case before kicking off. Any throttle pressure interrupts the braking process.

KATOOM

Ya use them all the time otherwise they can get sticky from carbon buildup. The only time I shut mine off is while in 5th gear or slick conditions or when I just dont want it to engage for whatever reason.

shep1

I leave mine on all the time, no problems. last check on original factory service brakes showed over 50% lining material. Coming up on 90k. love my exhaust brake.

viper67

But mileage also would drop a fair amount I would think.

KATOOM

Using the exhaust brake would have no bearing on fuel mileage, if thats what you were asking.

viper67

It would have to. Your going along 70mph and you take your foot off the gas as there is a light ahead. Your speed will drop down way faster with the brake engaged than without. Without the brake, you can coast further. I know you can slightly depress the pedal, but 95% wont do that.

KATOOM

I understand what you're saying but its not like what you're thinking. The only time you'd choose to continue letting the exhaust brake slow you when letting off the fuel pedal is if you "needed" to slow. There would be no point in just letting off the pedal and having the exhaust brake randomly and continually engage. The equivalent to that would be driving along and every time someone lets off the fuel pedal.....they hit the brakes as well. The only people I notice doing that are people way to old to be driving.

In saying all that, I cant speak for how everyone sets up their exhaust brakes but all kits come with a main power override switch you mount in the cab. Some are dash mounted and some are shifter mounted. I have the shifter mounted switch which makes it very easy for me to switch the exhaust brake off while cruising along down the freeway in 5th gear. But at the twitch of my thumb, I can turn it on so that the exhaust brake engages in any other gear.

viper67

ok. I see. On the 2012 the exhaust brake is there. Its a button you turn on and off. If you turn it on, when you turn the truck off, you have to turn it back on again. Will need to re-think my lack of use.

KATOOM

That sounds like it could be inconvenient. I like the shifter mounted switch better. As much as I like how mine is so simple by having the ECM control the engaging, I really like how the 3rd gen exhaust brakes work whereas the ECM still controls engagement but will not engage below 25 mph. That right there would lessen the flick time my thumb goes through.