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 back 6-speed function 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: A number of improvements. 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, especially 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.

This is a TCM exchange-only upgrade.  See photos for TCM location on the passenger side.  We cannot program your TCM.  A refundable TCM swap fee will be automatically added to your cart in checkout, return shipping instructions included.  Contact us if you elect to send in your TCM in advance and avoid this charge.