Exhaust brake - any disadvantage?

[CraigSmith]

So the older exhaust brakes caused problems with the transmission thrust bearing. I haven't heard about that any more. Are there any disadvantages to using the exhaust brake aside from poorer mileage? It seems it would help keep combustion temperatures up (and the manual recommends it for idling) and result in cleaner burning. Or does it create more problems with other compenents?



I try to use it when cold, but ironically it often doesn't go on when it's really cold. Maybe the oil has to heat up a bit?

 

[Hoefler]

The exhaust brake has no effect on fuel milage. When the exhaust brake engages, except at idle, there is no fuel going through the injectors.

 

[CraigSmith]

It itself isn't using fuel, and if you are driving a constant speed engaging the accelerator it doesn't activate, but the fact that it reduces mileage in general is documented. In non-constant-speed driving the braking effect when you would otherwise be coasting causes more fuel to be burned over a given distance. But the extent of the impact depends on the driving style/situation.

 

[HBarlow]

So the older exhaust brakes caused problems with the transmission thrust bearing. I haven't heard about that any more. Are there any disadvantages to using the exhaust brake aside from poorer mileage? It seems it would help keep combustion temperatures up (and the manual recommends it for idling) and result in cleaner burning. Or does it create more problems with other compenents?

I try to use it when cold, but ironically it often doesn't go on when it's really cold. Maybe the oil has to heat up a bit?

Use of the exhaust brake will cause you no problems whatsoever. My '01 and '06 both had a Jacobs Exhaust Brake and both were used 100% of the time.

The exhaust brake did cause reverse thrust bearing problems in the automatic transmissions but only on 2005 and earlier trucks that were not approved for exhaust brake use by Dodge or Cummins. After years of development and testing Dodge and Cummins finally authorized use of the Jacobs Exhaust Brake on trucks with the 48RE automatic beginning with model year 2006 and it could be ordered from the factory with exhaust brake. As soon as it was authorized I bought one.

Technically, our new ISB6. 7 engines do not have an exhaust brake. Our engines have a variable geometry turbocharger which is cabable of closing and providing an exhaust braking function.

To remain free of soot build up and continue to operate smoothly our turbos should be normally exercised from full boost to full closed (exhaust braking). That means use of full throttle and full boost on hard acceleration loaded or climbing a grade and, also, full exhaust braking.

 

[Hoefler]

Learning to drive it with the exhaust brake on is something all new 6. 7 diesel owners have to go through. If you want to coast with out the brake engaged, you simply apply very light pressure to the foot feed, it will allow you to coast with out any braking. If you play with it a little, you will find it. This is what is happening while using the cruise control.

 

[CraigSmith]

Thanks guys, I'll start using it all the time. Sometimes I turn the truck off at long stoplights and forget to turn the brake back on, but I'll just have to get used to it.

I knew it wasn't like a Jacobs brake but I wasn't sure if it could cause the same potential issues (and how well the new transmission had been tested) or if it had any other negative issues. I hadn't thought about it in terms of exercising the turbo.

One other question -- since this one is so quiet, do you still turn it off in areas that prohibit exhaust brakes?

I didn't realize the C&C keeps it on unless you turn it off; it seems they could offer a dealer-enabled option to do that without having to rig a relay.

 

[Lil' Dog]

IMHO, the EB feature of the VGT turbo is BETTER than any aftermarket exhaust brake. Its totally variable and adjusts to maintain maximum back pressure at any RPM, no aftermarket brake does that. No spring loaded relief valves etc to fool with.

It only "uses" more fuel on cold warmup as its adding load to the engine to warm up and disengages once the engine/ambient temperatures are above set point. If you are concerned about this fuel consumption, only use the EB once you are moving and need it.

 

[JHumphries]

... One other question -- since this one is so quiet, do you still turn it off in areas that prohibit exhaust brakes?...

I haven't seen any areas that prohibit exhaust brakes, only compression brakes.
Those signs are all over the cities across the water from Seattle.

 

[Mikey-KE7LBB]

The trucks are too quiet in stock form to violate ANY city ordinance!! And if someone wanted to argue the point... All of the signs I see specify "Jake Brake" and that is a trademark!!

 

[Newt]

Signs I've seen in Texas say, "No Engine Brake".

I think they're talking about the HDT trucks that really make a racket with the brake engaged.

Newt

Newt

 

[JDennis]

H Barlow



Regarding "Reverse Thrust Bearings"---I have a 2003 5. 9 HO with 48RE--155,000 miles---am considering the BD Eqipment Exhaust Brake with Pressure-Loc to maintain TorqConv pressures--Would the "thrust bearings" still be considered a potential problem in this situation?--Appreciate your comments--Thanks in advance--

JDennis

 

[CraigSmith]

IMHO, the EB feature of the VGT turbo is BETTER than any aftermarket exhaust brake. Its totally variable and adjusts to maintain maximum back pressure at any RPM, no aftermarket brake does that. No spring loaded relief valves etc to fool with.



It only "uses" more fuel on cold warmup as its adding load to the engine to warm up and disengages once the engine/ambient temperatures are above set point. If you are concerned about this fuel consumption, only use the EB once you are moving and need it.

I'm not actually too concerned about fuel consumption, I gave up on that. It is odd that in order to reduce emissions we have to burn more fuel, and I wonder what the net effect really is, but I don't lose sleep over it.



In my experience so far it doesn't seem like the EB provides much braking compared to a jake brake, but I'll take what I can get. The lack of an EB was the whole reason I didn't get the diesel back in '04.

 

[Lil' Dog]

I would agree that the ExB is not going to give the same retard as a true engine retarder like PacBrake or Jacobs. But with the engine size, you wouldn't be able to cost effectively design that into the valve train. But if you compare any of the aftermarket exhaust brake kits out there, the OEM is a pretty nice unit.



If you could get similar numbers to the larger 15-18L engines for retarding power, that would be scary. 300hp retard? Talk about compression skid!:-laf

 

[JHumphries]

... Talk about compression skid!:-laf

I did that with my 2010 coming down a wet hill unloaded!

 

[EOwen]

exhaust brake sqeal

I have a 6. 7 with the factory exhaust brake (VGTurbo) with 187K miles.

I just noticed it starting to squeal when this engages.

I replaced the serp belt since it was pretty chewed up on the top surface and had left alot of belt matl on the idler pulleys etc.

Anyone else have any experience with exhaust brake squeal?



thanks for your help.

 

[Hoefler]

Normal, now to make this long enough to post.

 

[Wiredawg]

The EB on the C & Cs w/ the Aisin auto may be more effective than the 2500/3500 setups w/ the 68RE. My 09 works much better than the BD on my 02, especially at lower RPM. Both are cool and work well. ,but the 09 is more consistent throughout the RPM range.



wiredawg

 

[HBarlow]

Signs I've seen in Texas say, "No Engine Brake".

I think they're talking about the HDT trucks that really make a racket with the brake engaged.

Newt

Newt

An "engine brake" is very different from an exhaust brake and much noisier. An engine brake actuates the valves to create compression braking.

 

[HBarlow]

H Barlow

Regarding "Reverse Thrust Bearings"---I have a 2003 5. 9 HO with 48RE--155,000 miles---am considering the BD Eqipment Exhaust Brake with Pressure-Loc to maintain TorqConv pressures--Would the "thrust bearings" still be considered a potential problem in this situation?--Appreciate your comments--Thanks in advance--
JDennis

JDennis,

I've been out RVing for a few days and missed your post.

I don't know anything about BD products or the claims they make but I can tell you this:

At the TDR Rally held at the Cummins Mid-Range Engine Plant at Columbus, IN in summer of 2002 just weeks before the new HPCR engine and Gen III trucks were introduced we attended lots of briefings with Dodge, Cummins, and Jacobs engineers to discuss the new trucks. Carlton Bale, a Jacobs Exhaust Brake engineer, told us that Dodge and Cummins planned to offer new trucks with automatic transmissions and factory approved exhaust brakes very soon.

As it turned out extensive testing first determined that the 2003 and 2004 truck ECM's lacked adequate computer size to contain all the necessary programming to integrate the engine, automatic transmission, and exhaust brake. When that limitation was overcome it was determined by extensive testing that the 48RE automatic contained a reverse thrust washer that would fail early under continual use of an exhaust brake.

One or more long-running threads here in the TDR website recorded the discussion that was updated occasionally by Carlton Bale, the Cummins/Jacobs engineer. I'm sure the thread is archived.

Finally, following upgrades to the 48RE, for MY 2006 Dodge/Cummins/Jacobs agreed that a 2006 Ram could be ordered from the factory with a dealer installed Jacobs Exhaust Brake sitting in the back floor. Neither Cummins or Dodge installed the exhaust brake on the assembly line but it appeared on the order sheet, dealer invoice, and MSRP. The eb was shipped in the original box resting on the floor behind the driver's seat. I ordered one of the early ones and it worked great for 230,000 miles.

You can draw your own conclusions as to whether your 47RE or 48RE will hold up to continued use of an exhaust brake while towing. My guess is BD will tell you it will. Unless BD also upgrades the transmission internals to handle the reverse thrust the limitation found by Cummins/Jacobs still remains. One of the excellent 48RE rebuilders often mentioned here on TDR could upgrade the transmission to handle the exhaust brake.

 

[JDennis]

H Barlow



Thanks for the info---I remember the articles by Carlton Bale, did not remember the final report, other than 2003/2004--etc, automatics were not approved for EB---however, lately I saw, not sure where, that most of the 2003 48RE's had corrected the "thrust washer" issue???---



Also, earlier in another "thread", some of the guys indicated that with my mileage

(155,000)--I may need to "freshen up" the transmission with EB installation---how extensive do you think "freshen up" means??--- Torq Convertor, with maybe a shift kit??---and address the "thrust bearing" issue---or Total Rebuild---Appreciate your comments--

Thanks in advance--

Jim Dennis