Leave engine brake on?

When I first learned to drive decades ago we never left the jake on all the time. Retraining to regain my CDL recently I noticed that the engines (and therefore the jakes) are more powerful than they used to be. Running again with my brother for a few months I only used the jake when I needed it, as before.

Then I went through training with Swift and for the first time I was introduced to the concept of driving with the jake on 100% of the time....

.... IMHO pure idiocy.

For one thing it makes shifting much much much (did I say much?) much harder. Especially if you are new to driving you need to learn the rhythm of shifting. Without the jake it's a "one-and-a-two" rhythm to disengage and then reengage from one gear to the next. Using a jake during shifting makes that rhythm faster and your chances of missing the correct rpm's to reengage into a new gear is much greater.

Second, as noted above with the more powerful engines and jakes if you are driving without the cruise control on and let up on the accelerator then the drive train starts actively braking. If you are trying to moderate speed in traffic this can result in quite a bit of stress if you are accelerating and decelerating frequently, especially in lower gears. I'm all about trying to be smooth when I drive, especially in inclement conditions. Having a jake on full time interferes with smooth transitions of speed.

If you have a trainer that wants you to have the jake on 100% of the time, fine... just do as he/she says. But once you get into your own truck start experimenting with driving without the jake on. Only engage it when you need it. You will most likely find that your shifting is smoother, you won't grind gears nearly as much (or at all), and your ride will be a lot smoother.

Ever see those guys in the truck stops riding a bucking bronco? A lot of the time that's because they have the jake on shifting in low gears. Don't be that guy...

 

Depends on the truck partially. I leave it on most of the time unless I'm going slow and don't want it jerking me. All the KW's I've driven, if you have the cruise control on and the engine brake, the engine brake only comes on when you hit the brakes/ brake pedal. I would turn it off when driving a manual. Now with the automatic in my truck I leave it on all the time almost, only slow traffic keeps the transmission in gear when slow otherwise when coming to a stop the truck disengages the clutch and possibly goes into neutral so no jerking effect.

 

Glad we have the two drivers with tons of experience spouting off about how it's bad or "pure idiocy". I guess those of us that have a little time don't know much.

As for shifting with the jakes on; if you know what you're doing, your jakes won't ever engage when you shift. But, what do I know?



Edit to add: I'm driving an Ultra-shift, these days and I've noticed that the truck itself will kick the jake on to make a shift quicker, even if I have the jakes turned off, so I guess even the truck doesn't know as much as some.

 

I use my jake to up shift in the mud, or when real heavy on a sharp short incline. It is left on when on cruise, because I set it at the 10 over limit so I dont want it free wheeling any faster. Of course, its always on when I am slowing down.

 

leaving the jake on all the time is like wearing a green shirt with brown pants and a blue tie. beside that people will laugh at you in the t/s when it engages a 5 mph. most young drivers would wind up better drivers if they didnt have a jacob brake. that my story and i am sticking too it. be safe out there

 

They should all be re-written as noise ordinances as it is a safety hazard to limit the use of a safety feature.

I frequently ignore engine brake ordinances, as my truck with the jake brake on at 1500 RPM's is still quieter than the straight pipe truck next to me with the jake off.

 

Any unnecessary or unintentional braking hurts mpg.

 

Right out of the FL Columbia manual:

 

I have always driven w/ jake on and have seen no ill effect. Learned to shift w/jake and a 9 speed hauling gravel, could not get to next gear with out it.

 

Not sure what you mean. It sounds like you're saying the engine brake will cause you to slow down for no reason and then you'll waste fuel getting back up to speed.

I assumed the OP was under the impression that using the engine brake to help slow when you actually need to slow would hurt fuel mileage.

You'd have to be stupid to be slowing for no reason.