When I drive, especially when I know I'll be going down grades I like to have my jake brake switch "on". Now I been wondering is this a bad habit for me, is it bad for the truck? I like to know that when I let off the throttle to go down grades that my jake will be there to slow me down if I do need to gear down. It's not any nervousness about going down grades or anything, maybe it's just lazyness I dont know but I seriously was wondering if it is or isnt bad for the engine to just leave your jake switch on? Thanks.

 

The only time my switch gets turned off is when I am in a city, or at a standstill on a freeway.

 

Doesn't hurt a thing.

The engine brake will not energize untill you let all the way off the throttle, with the clutch engaged.

If you have a Cat engine, you can leave the cruise control "on off" switch in the on position and that will keep the engine brake from coming on until you apply the vehicle's brakes, this makes it nicer for shifting without the clutch, as you don't have to worry about the engine brake coming on when you let off the throttle to upshift.

 

Exactly. I have mine on 24/7 except for winter time on some occasions and running empty in the rain.

 

Ahh, thanks splitshifter, I never realized you could do that, unfortunately I dont have a CAT engine I drive a Volvo with the Detroit engine dont know if it does that, but I'll give it a try thanks for the info, I'm glad to hear I'm not hurting anything in the engine doing that. I dont know what got me thinking about it one day and so I said better get on CAD and ask huh?

 

I guess I never really got the hang of "floating" with the jake on. High? Med? or Low?--

I guess part of the reason was the first truck I ever drove with a jake- also had super 10 too. Which at the time was rather a lazy man's transmission anyway-- break torque with throttle- rev up- flip the switch- and she engages as the rpms drop slighly--- that jake on- makes it all too quick--

but, yeah- I've known many drivers that like shifting with the help of the jake.

 

The only thing you have to really watch is that you aren't using your clutch to keep the jake from engaging by resting your foot on it.

 

I try to remember to keep mine OFF-

nothing worse than climbing a grade-- and forgetting it's on- (and you suck at floating with it on) and you're using progressive shifting- waiting to almost bottom out each gear before down shifting-- then you try to float( habit) downshift-- and the jake+ the sudden pull of gravity--- and you miss that 1 lower gear completely.

 

If you're going down a grade without the jake, what are you using? The foot brake? That will mean using the foot brake many times, and for longer periods. The foot brake is a wonderful thing. Helps you avoid rear-ending another vehicle on the road in front of you, but when you use it going down a hill, it tends to heat up. The latest version of the CDL manual that I've seen says that this contributes to CRACKING OF THE DRUMS. It also means that if you NEED the foot brake when you get to the bottom, it may not be as effective because of " FADING" when you get it hot.

By not using the jake when going down a grade, or even using the jake, but in too high a gear so that you must use the foot brake on your way down, you could be setting yourself up for disaster at or shortly after the bottom when that brake suddenly becomes important.

You can tell the true professional driver on the way down a grade. If you watch, he/she may be going slower, but the brake lights very seldom, if ever come on. The gear is selected so that the engine braking torque is about equal to the pull of gravity, and the engine controls the speed all the way down. That is the theory behind the design of the engine brake.

So, by using it, no, you will not do any harm to anything inside the engine. However, if you use the foot brake instead, you do stand a chance of having cracked brake drums on any one or several of the wheels. And, that becomes dangerous even when you are not going down a grade. I've seen pieces of brake drum on the shoulder of the road after getting to the bottom of Monteagle, TN, on the eastboung side. And, I really don't have to wonder what made the brake drum come apart.

 

In 15years I've never seen a brake drum- just suddenly "crack" on a driver- heading down a grade- they usually crack- if they've been super-heated to many times(tempered)- or if the knuckle head that then adjusted the brake- didn't back it off 1/4 turn-- this usually shatters that "tempered" drum the first hard application out of the shop.

or if they are super hot(on fire) and some one pisses on it- throws water on them--- usually- you'll see trucks completely on fire- and burnt to the ground.

but you're completely right about selecting the right gear to start down the hill-- and every driver should know how to descend a grade without having use of a jake without smoking their brakes. If you got a heavy load- and you start down a 8%- 40 mile grade- and you start down in High gear thinking your Jake is gonna do the whole job-- you're still going to be smoking before 1/2 way point. The jake is a great "helper" but shouldn't be considered a cure all- for poor planning.