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View Full Version : BD Exhaust Brake On Duramax\Allison



EIS01
05-11-2002, 20:00
I was wandering if anyboy is using a BD Exhaust Brake on a D\A combo? Does the transmission work well with this setup? I did not know if it would cause problems with the engine or tranny with the grade braking feature. Do people use exhaust brakes on other diesel trucks with automatic transmissions, or is it only possible because the Allison locks the torque convertor. My truck brakes real nice with the Allison as it is, but was thinking about adding an exhaust brake, I tow pretty heavy most days. Also, are they difficult to install? Thanks for your input in advance. Kevin

Jake99Z71
05-11-2002, 21:09
EIS01,
I've got one on my truck. Real easy to istall. If you would like I can email you the installation instructions. I like the added braking power. You can run exhaust brakes on automatics but you need to be able to lock the torque converter and raise line pressure to hold the gear. But we are lucky here because the Allison already has both for us.

pontiac_m18
05-11-2002, 23:47
eiso1, you can go to = www.trailerlife.com & go to the forums. There you will find all your questions about exhaust brakes on trailers!! Very interesting reading!! Howard :D :D :D

rberner
05-12-2002, 07:40
Hey Pontiac:

Maybe I'm blind but I looked for an hour on the trailer site and couldn't find anything about the exaust brakes.

Could you point me to the right forum

Thanks Roger

EIS01
05-12-2002, 16:54
Thanks for the replys. That answers a couple of my questions. The other question had to do with noise...I was wandering if it sounds neat? smile.gif Hopefully like the big trucks...and can you turn it on and off with a switch? Also, is it real effective, in other words do you think it helps a lot over the already good Allison braking? I don't know much about these things and did not want to spend all that money, just to be disappointed. Thanks again, Kevin

Jake99Z71
05-12-2002, 18:23
EIS01,
It sounds good not like the big trucks. I am running stock exhaust. Yes, you can turn it on and off with a switch besides a micro switch on the throttle pedal. Well to put it simply I can stop in a shorter distance using it over the standard grade braking. At times it has enough force to throw you out of the seat.

IndigoDually
05-12-2002, 20:44
The noise that you hear on big trucks is a "Jake Brake" or Jacobs engine brake. It works with the valve train to provide braking assistance. Some lighter heavy-duty trucks have exhaust brakes instead. The exhaust brake applies back pressure to aid with braking. When it is activated the exhaust will not have that cool sound, it will probably sound more like a vaccum cleaner.

John

pontiac_m18
05-12-2002, 21:46
EISO1, FOUND IT!! Go to www.trailerlife.com, then forum = rv.net = then search. type in exhaust brakes & be sure to change to 1 yr. search!! There are about 100 topics. There are 10 of which are related to the duramax alone. E-mail me if you need help!! Their web site say alot also! www.bd-vfi.com Howard - howard_m18@yahoo.com :eek: :eek: :eek:

[ 05-12-2002: Message edited by: pontiac_m18 ]</p>

Amianthus
05-14-2002, 09:04
I don't know what psi valve springs the Dmax has in it (the Cummins has 60psi springs), but one thing to consider is that the valves may float if they aren't strong enough and they could possibly contact the pistons at the wrong time. Obviously that will cause damage to the engine.
We have a turbo mounted exhaust brake on our firetruck (Cat 3126B) with an Allison automatic. The brake is controlled with a servo on the automatic. The transmission determines when the brake is on. That way the tranny can shift first and then apply the brake. I would think that this would be the best way to run the brake, if GM would allow it.

As far as sounding like a vacuum cleaner, only on a V-8. Mine sounds just fine. Just like it should. tongue.gif

IndigoDually
05-14-2002, 09:11
I drove an International with a 300hp./Allison combo (unsure if Cummins). When exhaust brake engaged there was the sound of air (exhaust) pushing through an opening. There was not noise just more like air rushing. Similar to putting your hand over the end of your tailpipe now.

John