Product Description

Background:  In 2006 and 2007, all GM medium duty (4500 and 5500) Allison 1000 equipped vehicles, including motorhomes, have 6-speed capability, but the existing transmission control module (TCM) software limits to 5 speed.  The 6th gear is disabled.  With higher gear ratios, the resulting high rpms are fuel wasting.  Optimum cruise rpm is 1800.  This replacement module gives you the intended 6-speed operation without any other hardware modification.  Plug and play, your existing TCM will be replaced with our custom reprogrammed factory module.

You will observe a 350 rpm reduction resulting in:

• A 2-3 MPG CRUISE ECONOMY IMPROVEMENT,
• QUIETER.  REDUCED ENGINE NOISE EMMISSIONS,
• INCREASED ENGINE LONGEVITY,
• INCREASED OIL CHANGE INTERVALS,

2 Programming Options:

FACTORY SHIFT PACKAGE: Shifting behavior should be the same. You may notice when towing, there is a lot of shifting between 5^th and 6^th gear (hunting), typical factory behavior.  Our CUSTOM REFINED option addresses this behavior.

CUSTOM REFINED SHIFT PACKAGE: Multiple improvements over the stock shift schedule.  You should notice less 6^th gear engagement during high throttle, lower speed operation (hills and headwinds). This is intentional, intended to reduce gear shifting (hunting) between 4^th, 5^th and 6^th gears, also useful with larger tires. You should also note that the truck is less “jerky” during unloaded and “in-town” driving, due to changes made to torque converter lockup.

IMPORTANT:  2006 OR 2007 YEAR AND VIN CODE “2” or “G” (8^th DIGIT IS “2” or “G”.)  Your VIN will be required, kindly provide it with your module, or contact us separately.  We can also supply a VIN for custom non-factory projects.  Ship your module to us, or local drop off service also available.

SUPPLY CHAIN NOTE:  Since these TCM’s are in shortage with a very pricey $1500 core charge, most people will want to send in their TCM with the programming payment to avoid that charge.  If you cannot be without your truck or motorhome for a few days, a refundable TCM swap fee of $1500 must be collected, swap return shipping instructions included.  Contact us to send in your TCM in advance and avoid this charge.