anyone got an exhaust break on a duramax/allison? What maker.
Do you have to install anything to make the TC lock up or does the allison lock up enough already?

The best I've seen is the BD, have known of the Banks to have problems. The converter will stayed locked pretty well if you use "Tow/Haul", and then the downshift programing works well also.

dont bother with an exhaust brake...if using tow/haul and the allison grade braking doesnt slow you down enough, the trailer is too heavy...JMO.

towing heavy thru hills and steep long grades Ive never found myself riding the brakes once the trans downshifts.

in tow/haul mode the allison locks up in 2nd gear at ~20mph and stays locked from there on up and down, unless speed drops below 20mph in 2nd gear, OR you brake hard enough to cross the ABS threshold.

I live in the california sierras and tow all over the place in california, the allison does do a great job of holding the load back, just wondering how much retarding factor you gain with the exhaust break, and if you need the trans controller on the allison like you do on the fords and dodges.

Bought a banks, ran one trip and Ebayed the peice O shit*.
*IMO

I run the BD exhaust brake on my '02 Duramax. I have an 11' camper and a 18' trailer with the Jeep.

Living in BC we have our fair share of mountains. The factory tow haul mode works well but I hated seeing the motor climbing to redline when i use it. The exhaust brake helps hold the truck at a constant speed. I'm happy with it. It makes a much bigger difference than the factory tow/haul mode.

I haven't noticed any need for an aftermarket trans controller.

there is no aftermarket trans controller availible for the Allison. The ATS one fizzled after some unsolvable issues/problems developed, and PCS has said they have had an Allison controller in development for over a year... :rolleyes:

the engine is balanced to 5,000 rpm. If the RPM in grade braking rises to a point of hurting the engine, the TCM will command an upshift to lower RPM and prevent engine damage...nothing to worry about.

there is no aftermarket trans controller availible for the Allison. The ATS one fizzled after some unsolvable issues/problems developed, and PCS has said they have had an Allison controller in development for over a year... :rolleyes:

the engine is balanced to 5,000 rpm. If the RPM in grade braking rises to a point of hurting the engine, the TCM will command an upshift to lower RPM and prevent engine damage...nothing to worry about.


so it wont hurt our dmax's @ 3500-3600 ?

yeah that is right. the older duramax had a red line at like 3600 I think it was, when the LLy came out (I think it changed with the lly) they removed the redline up to like 5000 i think it is. I think they did this because people were probably worried about reving into the red on down hills. The computer wont let the motor go into the red under throtle. Amd like its been said if the motor does rev to high going down hill the computer will just shift the trans up, I dont think there is much you can do to hurt the set up that hasnt been thought of and doesnt have a fail safe of some sort. if you have ever got the motor up into this range when going down hill you can really feel the motor slow you down or at least hold ya there, even with alot of weight.

dont bother with an exhaust brake...if using tow/haul and the allison grade braking doesnt slow you down enough, the trailer is too heavy...JMO.

towing heavy thru hills and steep long grades Ive never found myself riding the brakes once the trans downshifts.

in tow/haul mode the allison locks up in 2nd gear at ~20mph and stays locked from there on up and down, unless speed drops below 20mph in 2nd gear, OR you brake hard enough to cross the ABS threshold.


I disagree, pulling aroubd 9-10,000lbs through the mountains this weekend while the tow haul works great(I don't yet find a need for an exhaust brake)but it would occasionally push through the allison, 8-9 miles of 7-8% grades. I don't think I am towing too much for this truck.

My truck is an 05, and I have used a friends 04.5 before, same exact truck, LLY and all that and I swear his tow haul worked better than mine, nearly the same load and it would maintain whatever speed you set it at at the top of the hill. I wouldn't be surprised if some worked better than others:)

BTW there is no reason to worry when it revs really high coming down in T/H, mine was in the mid 4's this weekend a few times:)

so it wont hurt our dmax's @ 3500-3600 ?


bahh not in the slightest. Jess Spruill (one of the 10 second dmax's) has wound is engine to nearly 5800rpm and its still running fine. Being a V8, high revs are not going to hurt it as easilly.

J kimmel I completely agree with you. The Allison grade braking is totally hit or miss. Sometimes mine works awesome and cranks the engine right up slowing me down well with heavy loads, other times Ill ride the brakes forever and the trans just sits there like a retard sitting on its hands. The Allison TCM is too smart for its own good and sometimes it just is a pain in the ass. The grade braking program in the Allison TCM is a completely dynamic highly complex proprietory algorithm that takes MANY different parameters into account when deciding if a downshift is necessary. It is not like the simple passive grade braking like in the Ford TorqShift, which downshifts regardless the second you step on the brake pedal. Most of the time Id actually rather have the simple "step on the pedal, trans downshifts" idea...but then again there are rare occurances when that would not be desired.

Ive tried to find out about what parameters the Ally TCM takes into account when it decides if a downshift is neccessary, but its very secret and proprietory, just like everything else to do with Allison. :rolleyes:

from what ive found, I think it looks at the rate of accelleration, how throttle position, how fast you lift from the throttle and press the brake, how hard you press hte brake, and lots of other things.

I can "ALMOST" make it downshift "on command" by if Im at the top of a long down-sloping hill, I actually accellerate down the first 100 feet or so of the hill so im gaining speed, then I quickly lift and "dip" into the brake with a smooth hard "tap". The trans will downshift 8 out of 10 times and work like its supposed to when I use this "technique", I dont know why, but it seems to work. The times it doesnt work I just move the shifter down to "3" manually.:confused:

bahh not in the slightest. Jess Spruill (one of the 10 second dmax's) has wound is engine to nearly 5800rpm and its still running fine. Being a V8, high revs are not going to hurt it as easilly.

Got a link? I'd love to see what he's done to his truck. Quickest Dmax I've seen is around the 12sec mark.

J kimmel I completely agree with you. The Allison grade braking is totally hit or miss. Sometimes mine works awesome and cranks the engine right up slowing me down well with heavy loads, other times Ill ride the brakes forever and the trans just sits there like a retard sitting on its hands.

Yet you argue against the need for an exhaust brake? :D Between this and the fact that I've got an LB7 with the lower redline it convinced me to put the exhaust brake in. I agree GM did a good job of sorting these trucks out and I know the tranny will upshift before it does any harm but I like having the peace of mind knowing the exhaust brake is there too.

Between this and the fact that I've got an LB7 with the lower redline it convinced me to put the exhaust brake in. I agree GM did a good job of sorting these trucks out and I know the tranny will upshift before it does any harm but I like having the peace of mind knowing the exhaust brake is there too.


FWIW, ive heard of an engine being puked with an exhaust brake, but never heard of an engine being puked when being revved high with grade braking.

I mean when the allison grade braking works it holds the trailer just fine:flipoff2:

for the umteenth billionth time, the LB7 and LLY's DO NOT HAVE A LOWER REDLINE. Its a freaking reprinted tachometer on the instrument cluster, nothing more. You can rev any duramax to 5,000 rpm (UNFUELED; there is a difference) safely. Now if you are actually remove the rev limiter, and run the engine with fuel (power) up at 5,000 rpm thats a different story.

There have been at least 2 10 second duramax's around for a while.

Buck and Jess Spruill, 2003 extended cab/short bed, fully street legal in every way, LB7, TTS Extreme tuning, modded CP3, Crower/TTS rods, Suncoast V allison, stock everything else. Yes, he is still running the engine's original stock turbo and its holding up fine. This truck cuts a 1.3x 60 foot time.:eek:

No Limit Diesel Performance, 2001 regular cab long bed, fully street legal, LB7, TTS Extreme, bigger injectors, ATS Aurora 5000 turbo, ATS Allison trans, Crower Rods, everything else stock.

NLDP was running stock rods for a while. Engine had 131,000 miles of the shit beaten out of it, running 11.70-11.00 seconds flat all season, truck pulling, then this season they got 3 10 second passes out of it, spit the #8 rod on the 3rd 10 second pass like all >825 rear wheel hp duramax's do.

now I know cummins guys are running 10's with stock rods, but not on stock turbos or stock trans hard parts:flipoff2: :D

From here: http://www.thedieselpage.com/features/2006MY.htm

http://www.thedieselpage.com/features/2006-05c.jpg

"Many Duramax diesel pickup owners have been confused about the tachometer redlines used in previous model-year trucks. All previous model-year tachometers began with a dashed redline beginning at 3200-rpm (as shown in the 2001 photo below), and a solid redline beginning at 4800-rpm. The dashed redline was meant to indicate the rpm limit while under load, and the solid redline was intended to indicate the engine rpm limit while in grade-braking. The engine could run to as high as 4800-rpm while in grade-braking, which concerned a lot of pickup owners who mistakenly thought they were running their engine well past the "danger zone". The new tachometer (shown above) now eliminates the dashed redline entirely."

http://www.thedieselpage.com/features/2006-14c.jpg



:flipoff2: