Do I have an Exhaust Brake or an Engine Brake

[kidoo]

Hi, do I have an Exhaust Brake or an Engine Brake? I have a ISB 300HP, 2003. I have a switch and it slows the MH down when I use it.

I cannot see any parts on the exhaust (except the turbo) I guess it would be after the turbo if it would be an exhaust Jacob Brake?

If it is an Engine Brake, what is the difference and where is it?

Thanks.

[Mr_D]

Exhaust brake on that year ISB. You usually don't get an engine brake till the ISL or larger engine although I have heard of a few on the ISC but have never seen it on one.
Engine brake changes the valve timing to basically use the engine as an air compressor and is much better at slowing you down than an exhaust brake

[WILDEBILL308]

Well Kidoo it would be helpful if we had more info as you haven't filled out your profile or added basic information to your signature. See mins and Mr Ds sig. What you probably have is the retarder that is built into your transmission. There is a lot of confusion on this even by the coach builders. In my Allason 3000 transmission manual it is called a Retarder but in the owners manual it is called an engine brake and the switch is labeled that way. Here's a excerpt from my Allison book.

RETARDER
The self-contained retarder is at the output of the transmission and consists of a
vaned rotor which rotates in a vaned cavity. The rotor is splined to and driven by
the output shaft. An external accumulator holds transmission fluid until the
retarder is activated. When the retarder is activated, the fluid in the accumulator is
pressurized by the vehicle air system and directed into the retarder cavity. The
interaction of the fluid with the rotating and stationary vanes causes the retarder
rotor and output shaft to reduce speed, slowing the vehicle or limiting speed on a
downhill grade. Refer to USING THE HYDRAULIC RETARDER for additional
information.
When the retarder is deactivated, the retarder cavity is evacuated and the
accumulator is recharged with fluid.
Bill

[Skip426]

IF ! your coach is on a Freightliner chassis,
Then a call to the Freightliner Free help line 1-800-385-4357.
With the chassis serial number , will get you an engine and transmission serial number.
A call to Cummins Care, with the engine serial number. 1-800-343-7357
will provide info on exhaust brake , or possible VVT turbo, not sure what year they changed over.
The a trip to the Allison transmission web page and a browse through " My Allison " with your trans S/N will give you all the info you need there.

Allison Transmission Home

Because the additional cost of the Allison transmission, with Hydraulic Retarder, they were seldom used in anything but very high end coaches.
Although the dash control on my coach is labeled " RTDR " it is only equipped with an exhaust brake.

EDIT: Please take the time to fill out a signature line.
From your " User CP" on the left side of the page click " Edit Signature" type in your coach info and click save at the bottom of the page.
The info automatically appears below your posts and you don't have to type it in every time. More info = Better answers.

[dons2346]

You have an exhaust brake

[kidoo]

Thanks to all. I just got an answer from Quickserve Cummins and they say my engine has an Exhaust brake. No engine brake was available for this engine in 2003. I also found on the cummins Quickserve that the Exhaust brake is part of the turbo.

Note: Exhaust braking is an integral function of the VG turbo on ISC/ISL/ISB CM2150.
https://quickserve.cummins.com/info/..._nondodge.html


There was a post a few years ago saying that he disconnected the EGR on a ISB engine in order to keep the turbo clean and working. From what I get from this, the engine brake is a function of the VGT ring/vane in the turbo itself, closing for braking, opening depending on the demand. The turbo and VGT are actually braking or boosting the engine.
http://www.irv2.com/forums/f123/cumm...4-a-90078.html

[Mr_D]

I didn't realize they used the variable vane turbo in 2003.
The only RV that is known to use a transmission retarder is the Foretravel.

[WILDEBILL308]

Mr D hear is a quote from my Allison owners manual.
A hydraulic retarder is available on all of the models covered in this manual. The
retarder is activated and controlled in various ways. The control depends upon the
vehicle type and particular duty cycle. Both manual and automatic controls are
available. Automatic controls are applied by the ECU. Some types of controls and
the amount of retarder application are shown in the Types of Retarder Control
table.
This manual covers the 3000MH and 4000MH and a couple of others.
Bill

[Mr_D]

Originally Posted by WILDEBILL308

Mr D here is a quote from my Allison owners manual.
A hydraulic retarder is available on all of the models covered in this manual. The
retarder is activated and controlled in various ways. The control depends upon the
vehicle type and particular duty cycle. Both manual and automatic controls are
available. Automatic controls are applied by the ECU. Some types of controls and
the amount of retarder application are shown in the Types of Retarder Control
table.
This manual covers the 3000MH and 4000MH and a couple of others.
Bill

That is correct, as far as it goes. What I said is also true, only Foretravel uses the retarder in their RV's