What kind of engine brake do I have?

[Statgeek]

I have a 2013 Fleetwood Discovery 40G on a Freightliner Chassis. My Fleetwood manual (which I have on PDF) shows this text:

Using the Engine to Slow
the Motor Home
To use the engine as a braking force, select the
next lower gear. Engine braking provides good
speed control for going down grades. When the
motor home is heavily loaded, towing, or the
grade is steep, preselection of a lower gear prior
to the grade may be desirable.
Gear preselection means the selection of a
lower gear to match the driving conditions you
encounter or expect to encounter. Preselection
will give you better control on slick or icy roads
and on downgrades. Downshifting to lower
gears increases engine braking. The selection
of a lower gear often prevents cycling between
a gear and the next higher gear on a series of
short up-and-down hills.


This suggests that the engine break merely downshifts, but that's not my experience. With the engine break on, the minute I take my foot off the accelerator I can feel a 'pull' of the engine break (before it shifts any gears).

Any Fleetwood owners out there (or maybe this is a Freightliner question) know what kind of engine break I have? I know only that there are different kinds of engine breaks ("pac" breaks, exhaust breaks, maybe others?) and I'm just curious what I have. I'm also curious about what difference it makes among them... Thanks!

[450Donn]

What motor?
Cummins is likely going to have a sliding vane turbo. This acts as an engine brake. Allison Transmission? These use the transmission as a sort of brake.

[BFlinn181]

You need to give more information. Which engine? Transmission? Do you have a switch near driver to turn engine brake on or off? You might have either an exhaust brake or the sliding turbo vane as mentioned above. Not many RVs have Jake brakes, they are very noisy. Usually an exhaust brake has a switch to disengage it so it doesn't come on automatically when you release accelerator.

[Steve Ownby]

Originally Posted by Statgeek

I have a 2013 Fleetwood Discovery 40G on a Freightliner Chassis. My Fleetwood manual (which I have on PDF) shows this text: Using the Engine to Slow the Motor Home To use the engine as a braking force, select the next lower gear. Engine braking provides good speed control for going down grades. When the motor home is heavily loaded, towing, or the grade is steep, preselection of a lower gear prior to the grade may be desirable. Gear preselection means the selection of a lower gear to match the driving conditions you encounter or expect to encounter. Preselection will give you better control on slick or icy roads and on downgrades. Downshifting to lower gears increases engine braking. The selection of a lower gear often prevents cycling between a gear and the next higher gear on a series of short up-and-down hills. This suggests that the engine break merely downshifts, but that's not my experience. With the engine break on, the minute I take my foot off the accelerator I can feel a 'pull' of the engine break (before it shifts any gears). Any Fleetwood owners out there (or maybe this is a Freightliner question) know what kind of engine break I have? I know only that there are different kinds of engine breaks ("pac" breaks, exhaust breaks, maybe others?) and I'm just curious what I have. I'm also curious about what difference it makes among them... Thanks!

This is an oddly written couple of paragraphs which never directly mention a brake of any kind. Do you have a brake on/off switch? If so and it's switched on does the transmission select a lower gear when the brake activates?

Do you have a Cummins ISB engine? If so you likely have an exhaust brake that is actually the VG turbo doing extra duty. It seems to work well.

[Clayobx]

You may have a " engine retarder system" it is an electromagnetic system that closes the valves thus compressing the air in the cylinders, slowing or retarding the energy. Call FW with your FIN number or FL with your VIN number they will infirm you as to the type then you can search your system. On my 450 ISL I have the retarder system.

[Statgeek]

Sorry guys. I didn't provide enough info. I have a Cummins engine with Allison transmission. It is 380 hp and yes, there is an engine break on/off switch that I use to have it on or off. I believe my engine is an ISL but I do not recall the liters.

[Steve Ownby]

Originally Posted by Statgeek

Sorry guys. I didn't provide enough info. I have a Cummins engine with Allison transmission. It is 380 hp and yes, there is an engine break on/off switch that I use to have it on or off. I believe my engine is an ISL but I do not recall the liters.

After 2010 the Cummins engine with a 380 hp rating is the ISC 8.3 liter engine:

http://cumminsengines.com/showcase-i...s=100#overview

More than likely the exhaust brake on your engine is based on the VG turbo. The Allison 3000 should be the transmission you have. When the exhaust brake activates you should see in the transmission display a 2 or 3 to indicate the transmission will start shifting down as rpm permits toward that gear. The transmission will select 6th when the exhaust brake disengages.

[lanerd]

The paragraph you provided is NOT for the engine BRAKE. Just manually shifting the trans to a lower gear is what that paragraph is describing. You need to look further in your owner's manual for additional info on the engine BRAKE.

It's my understanding that the ISB, ISC and some ISL (not sure of what date) Cummins only have the "exhaust" brake, commonly referred to as an "E Brake". All other larger Cummins engines (ISL's of more recent dates, and larger) have the engine compression brake..."C-Brake". I'm not 100% sure of these facts, but this was what was explained to me by our Cummins Mechanic.

Ron

[koda59]

On my diesel I have a jake brake. It has a switch for low or high

[Statgeek]

Originally Posted by lanerd

The paragraph you provided is NOT for the engine BRAKE. Just manually shifting the trans to a lower gear is what that paragraph is describing. You need to look further in your owner's manual for additional info on the engine BRAKE. It's my understanding that the ISB, ISC and some ISL (not sure of what date) Cummins only have the "exhaust" brake, commonly referred to as an "E Brake". All other larger Cummins engines (ISL's of more recent dates, and larger) have the engine compression brake..."C-Brake". I'm not 100% sure of these facts, but this was what was explained to me by our Cummins Mechanic. Ron

Understood. That is all that my manual has to say about the brakes...

[palehorse89]

Here are the specs. on your Coach, 380 Cummins = Exhaust brake

2013 Fleetwood Discovery® 40G Specifications

Engine: Engine Brand Name Cummins Engine Type I6 Diesel Pusher Cylinders 6 Horsepower (bhp/kW) 380 / 283.6 Horsepower RPM 2000 Torque (Ft Lbs/Nm) 1050 / 1423.6 Torque RPM 1400 Fuel Requirements Regular Fuel Type Diesel Turbocharged Yes Supercharged No Chassis Model XC-Series Chassis Brand Freightliner Displacement (l) 8.3 Carburetion Type Fuel Injected Transmission: Transmission Type Automatic Number Of Speeds 6 Overdrive Yes Transmission Brand Allison Wheels & Tires: Wheels Composition Aluminum Front Wheel Width (in) 8.25 Rear Wheel Width (in) 8.25 Number Of Axles 1 Tire Brand Goodyear® Front Tire (Full Spec) Goodyear® 275/70R 22.5 Rear Tire (Full Spec) Goodyear® 275/70R 22.5 Brakes: Front Brake Type Hydraulic Disc Rear Brake Type Hydraulic Drum Anti-Lock Brakes Standard Air Brake Standard Exhaust Brake Standard Technical Specifications: Length (ft/m) 41.62 / 12.7 Width (in/mm) 102 / 2590.8 Height (in/mm) 154 / 3911.6 Wheelbase (in/mm) 276 / 7010.4 Interior Height (in/mm) 84 / 2133.6 Length (ft/ft) 41 Length (ft/in) 8 Towing Capacity (lbs/kgs) 10000 / 4536 GVWR (lbs/kgs) 32400 / 14696.6 Fuel Capacity (gal/l) 100 / 378.5 Storage Capacity (cuft/gal/l) 374 / 2404.3 / 10590.2 Number Of Fresh Water Holding Tanks 1 Total Fresh Water Tank Capacity (gal/l) 100 / 378.5 Number Of Gray Water Holding Tanks 1 Total Gray Water Tank Capacity (gal/l) 75 / 283.9 Number Of Black Water Holding Tanks 1 Total Black Water Tank Capacity (gal/l) 50 / 189.3 Propane Tank (s) Standard Number Of Propane Tanks 1 Total Propane Tank Capacity (gal/lbs) 38.7 / 164.1 Seats: Seat Type Bucket Seat Material Leather Power Adjustable Seat Yes Reclining Seats Yes Swivel Seats Yes Seat Armrests Yes Number Of Seats 2 Number Of Rows 1 Exterior: Body Material Aluminum Sidewall Construction Fiberglass Number of Doors 1 Sliding Glass Door No Number of Slideouts 2 Power Retractable Slideout Yes Number of Awnings 1 Power Retractable Awning Yes Screened Room No Leveling Jack Type Front Power / Rear Power Power Retractable Entry Steps Standard Sky Light Standard Roof Vents Standard Exterior Ladder Standard Exterior Window Shade / Cover Standard Exterior Shower Standard Pass-Thru Storage Standard Exterior Wheel Skirts Standard Slideout Awning Standard Instrumentation: GPS Standard Voltage Meter Standard Fresh Water Holding Tank Gauge Standard Gray Water Holding Tank Gauge Standard Black Water Holding Tank Gauge Standard Trailer Level Gauge Standard Water Pump Power Display Standard Propane Tank Gauge Standard Identification: Generic Type (Primary) Class A Manufacturer Country USA Introduction Year 2009 Regional Availability All Regions Display Name Discovery® 40G Interior: Kitchen / Living Area Flooring Type Carpet / Tile Kitchen Table Configuration Chairs Kitchen Location Front Living Area Location Center Number Of Oven Burners 3 Overhead Fan Yes Layout Oven / Stove Microwave Oven Standard Refrigerator Size Full-Size Refrigerator Power Mode Electric / Propane Washer / Dryer Standard Sink Cover / Cutting Boards Standard Number Of Sofas 1 Sofa Material Leather Number Of Recliner / Rockers 0 Max Sleeping Count 8 Number Of Bunk Beds 2 Number Of Double Beds 0 Number Of Full Size Beds 0 Number Of Queen Size Beds 1 Number Of King Size Beds 0 Number Of Convertible / Sofa Beds 1 Master Bedroom Flooring Type Carpet Master Bedroom Door Style Conventional Door Full Size Master Bedroom Closet Yes Master Bedroom Mirror Doors Yes Master Bedroom Shades / Curtains Yes Master Bedroom Location Rear Bunkhouse No Bed Spreads Standard Number Of Bathrooms 1 Bathroom Flooring Type Tile Bathroom Location Center Toilet Type Porcelain Door Type Plastic / Glass Bathroom Sink Standard Bathroom Medicine Cabinet Standard Bathroom Mirror Standard Bathroom Vent / Fan System Standard Central Vacuum System Standard Sink / Faucet Standard Power Vent Fan Standard Electrical: Battery Power Converter Yes Air Conditioning Prewiring Yes Cable Prewiring Yes Phone Prewiring No Heat Prewiring Yes TV Antenna Prewiring Yes Satellite Prewiring Yes Washer / Dryer Prewiring Yes Exterior Plugs Standard Ground Fault Plugs Standard Solar Battery Charger Standard Generator Standard Other: Smoke Detector Standard Carbon Monoxide Detector Standard Propane Alarm Standard Emergency Exit (s) Standard Number Of Emergency Exits 1 Towing & Hauling: Size (in/cm) 2 / 5.1 Tongue Weight (lbs/kgs) 1000 / 453.6 Rear Hitch Type Receiver Heater & Cooler: Air Conditioning Type Automatic Heater Type Automatic Water Heater Tank Capacity (g/l) 16 / 60.6 Water Heater Pump Power Mode Electrical / Propane Water Heater Tank Bypass Yes Freeze Proof Insulation Standard Audio & Communication: Brand Name Sony Number Of Radios 3 Speaker Location (s) Interior / Exterior Surround Sound Yes Number Of Discs 1 DVD Player Standard Television Brand Name Sony Number Of Televisions 3 Exterior Entertainment System Standard Retractable Roof Antenna Standard Lights: Exterior Flood Lights Standard Convenience: Cruise Control Standard Air Suspension Standard Rear Video Backup Camera Standard Paint & Finish: Paint Standard Wallpaper Yes Interior Wood Finish Yes Curtains / Shades Standard Warranty: Basic Warranty (Months) 12 Structure Warranty (Months/Miles) 36 / 45000 Powertrain Warranty (Months/Miles) 36 / 50000 Chassis Warranty (Months/Miles) 36 / 50000 Drive Line: Driveline Type 4X2

[lanerd]

Originally Posted by koda59

On my diesel I have a jake brake. It has a switch for low or high

Actually, not quite true. All of the brake systems made by Jacobs Vehicle Systems can accurately be called "jake brakes," not just their compression release engine brakes. They also produce the Jacobs Exhaust Brakes and Jacobs Driveline Brakes, both of which are nearly silent.

The more accurate name of your system is an "compression brake".

I know, I know... picky, picky, picky.

[Gary RVRoamer]

All of the brake systems made by Jacobs Vehicle Systems can accurately be called "jake brakes," not just their compression release engine brakes.

Perhaps by you or another RVer, but I don't know of any experienced diesel tech or truck driver who would use "Jake brake" for anything but the Jacobs compression brake.

[BFlinn181]

Originally Posted by Gary RVRoamer

Perhaps by you or another RVer, but I don't know of any experienced diesel tech or truck driver who would use "Jake brake" for anything but the Jacobs compression brake.

LOTS of folks use 'Jake Brake' as a generic term for engine or exhaust brakes. I've wondered if I could use an exhaust brake in one of these places and argue the ticket over the fact that it's technically not a Jacobs compression brake.