Isx 550 In a kenworth C500....Jake shift?

I was always told jake shifting is a big no no.

 

The 500 and 600 cummins in my Freight's dont like to jake shift either

 

3 tranny's later he figures it out . least thats how many a bud wasted now lol

 

why do you want to jake shift ?

 

Look at what truck dr1c is driving its a C500 that is an offroad/onroad mostly off. When your running in soft ground or pulling very steep hills at slow speeds its nice to be able to get the next gear but you cant if the rpms wont drop faster than your road speed.
But to respond to the op. That is controled in the ecm not much can be done about unless you get a tune like PDI or something. My only suggestion is to try the engine fan. Leave it on and it will draw the rpms down a little faster.

Jake shifting is hard on the turbo. Its the turbo being spooled and spinning fast then the sudden back pressure that can cause the turbo to spin backwards in an instant that is the problem.

 

Bingo

But then we have the supa truckas. A local guy is border line psycho with jake brake. If the jake quit working, i dont think he could/would drive the truck. He gases on it just to let off and go blllaaahhh. Shifts just to hear blllaaahhhh. Gases on it again so he can let off and blllaaahhh. And it is his own truck, his fuel, his repair bill...

 

jake shift.that's funny.that is just sooo cool.i am impressed by jake shifting almost as much as the all ten gears thru the truck stop drivers.go ahead and jake shift that truck,driver,and go thru a couple of transmissions.ask your bossman,or woman,what they think of jake shifting-

 

I wonder what it is in ECM programming that allows engines paired with automated trannies to use the jake to speed up a shift, but not a standard?

 

The engine brake doesn't spin the turbo backwards. You would hear on helluva whoosh and be replacing broken shafts and ruined bearings every trip if it did.

The engine brake simply lets all of the cylinder pressure out at TDC. The energy spent compressing the air is wasted versus being overpowered and send back down by combustion. This is what slows the engine. The exhaust still goes out the exhaust the intake still comes in the intake.

Shifting with the brake on can be hard on things if you don't use your head. Run it only when needed. As mentioned soft soil and big hills with heavy loads. It's all about timing. You have to manage to get the trans out of gear before the Jake hits and get back on the throttle to cancel the Jake and into gear after the Jake is off but before you start accelerating. Essentially you are doing a very sped up version of what is normally done. It takes a lot of practice and you cant be sitting on the floor reclined into the sleeper with the radio cranked. You gotta be on your toes. The people who ruin trannies using this method are people who would've ruined them anyways. It's all about keeping the transmission fRom switching directions of torque. The method described takes the transmission from forward to neutral to forward. The people who ruin transmission s are the ones who don't care or pay attention. They take the transmission from forward to bang clang bang. Essentially they allow the Jake to put reverse torque on the transmission somewhere throughout the sequence at least one. Sometimes jumping between directions. Or there's the guys that just stab it in.

When used wisely it can help you get out of a rut. Most people will never need it though. I have a talk with every guy I catch doing it when not needed. Drive line parts aren't cheap.