I got to talking to an Allison dealer about unlocking 6th gear on a 2500PTS.
While it can be done, the process is bureaucratic and not guaranteed. There are two paths you can take:
- Allison and OEM of bus authorization
- PCM Performance (pcmperformance.com)
Before you start, any Allison 2500PTS manufactured AFTER June 28, 2006 is capable of taking advantage of the TCM being unlocked. Transmissions manufactures prior to this have hardware differences and must be altered (no guarantee) to work with the TCM flash. Each transmission has a date code. It follows this format YYMDD.
- YY is the last two digits of the year (06 for 2006)
- M is a letter that translates to the month (A is Jan, J is October)
- DD is the day of the month
Unfortunately, my date code os 06D28 - and manufactured prior to June 28, 2006 so mine is not able to take advantage of the TCM flash.
So here we go:
- For an authorized Allison dealer, follow the instructions in the PDF attachment.
- To go outside of the Allison authorization, go to PCM Performance - Alex will charge you ~$300-350 to flash your TCM or you can purchase a new one from him for $500.
Here's the mythical Allison instructions: http://www.pizoteadventures.com/down...ashRequest.pdf