JDGMC
11-22-2005, 08:18 PM
Well, I did a search and didn't find the answer I was looking for --- but it will be my luck that I screwed up the search. I would have guessed that this topic would have been discussed before and I just can't find it. If it was, and I missed it - sorry.
Anyway - Does anyone know if there is any truth to a rumor that I've heard that I could possibly have the internal parts for a 6 speed and further, that it could be possible to convert my rig to get six operational speeds???? I could use the milage increase.
Thanks for any info - I hardly ever post but do read here occasionally.
DJGMC
carhauler
11-22-2005, 08:22 PM
Look in ALLISON AFERMARKET section
DangerousDuramax
11-24-2005, 12:48 PM
I have heard a rumor that those of us with the 5 speed Allison alread have the 6th gear that it just isnt engaged thru the computer. Also heard that there are aftermarket companies working on new computer upgrade so that the 5 speed Allison will use the 6th gear.
RideRed
11-24-2005, 01:40 PM
Sounds to be pretty complex, i.e. the software for the trans is hard to reverse engineer---whole new computer between 5 and 6 speed too?
Plus that, another passage (external tube) has to be added to the valve body.
briano
11-24-2005, 06:37 PM
moving to Allison OEM section
Mike L.
11-24-2005, 07:26 PM
Sounds to be pretty complex, i.e. the software for the trans is hard to reverse engineer---whole new computer between 5 and 6 speed too?
Plus that, another passage (external tube) has to be added to the valve body.
All the experts say you only need a toggle switch. It was there all along and we idiots could not see it.
DURAtotheMAX
11-24-2005, 07:38 PM
yeah I think to get anywhere with this mod, we would need to load 4th generation software into a 3rd gen TCM. The 4th Gen TCM most likely wont work in our trucks because its completely different...runs on a 32 bit computer and speaks GMLAN only...whereas our (old) TCM's speak CAN and Class II. Physically, its "easy" (in terms of valve body mods). The challange would lie in the programming, OR somehow getting a 4th gen TCM to work in our "old" trucks. I thought it would be a great project at first, but ive given up on it...I have other projects to worry about and finish. Like the Suncoast IV kit thats still sitting in a box in my back hall...
--Ben