The engine brake works in conjuction with the autoshift transmission to make quicker shifts, so it's essentially always "on".

 

true the trans will over ride the switch for faster upshifting (when needed)
but if the switch is off that is the only way thay will come on

 

Full of shi^, plain and simple....lol

 

Thanks for all the replies. I thought my trainer was "FOS" but was in no position to say so!

I guess I'll stop flippiing the switch off when climbing hills! ops:

 

I've also had a couple of trainees that said the instructor told them you could use the "clutch-brake" to help you stop the truck.

If you understand a wiring diagram, look at the wiring connections for the jake brake. The switch that turns it on and off goes in series with the switches on the clutch pedel and throttle. If you're going uphill, you have the throttle engaged, right? With the throttle engaged, the switch on the throttle is open and the jake is disabled. That switch does almost exactly the same thing as the switch on the dash. BUT... the switches on the throttle and clutch automatically engage the jake when either pedel is released. In a manual shift, this could (and often does) reduce the rpm of the engine faster than you can react with the shifting lever.

On an auto-shift, (I have never driven one), I would expect to find that the computer that does all the work shifting, would also control the jake.

On my own truck, I never turn if off unless I'm going through a town with a restriction, or after 8PM if I'm near a residential area. Parents tend to get a bit irate if a loud noise, like a jake brake, wakes up an infant they've been trying to get to sleep for several hours. It's a matter of courtesy.

I know of NO instance that it effects the operation other than engine RPM during shifting, if you float the clutch. It's rather like the guy that tried to tell my wife that if she plays "country-western music" on the stereo, it will degrade the speakers and stereo components. My vote says it's a bunch of HOG-WASH.