Drivetrain› Automatic Transmissions and Components

DuraMax Tuner

6 Speed Conversion Kit

$1,999.00

SKU: D06C DM1361070080900

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

Upgrade your '01-'05 Allison 5-speed transmission to a 6-speed with this conversion kit from Duramax Tuner. This kit improves reliability, shift quality, and fuel economy, especially at highway speeds. It reduces RPMs by approximately 14% (around 300 RPM lower) during highway cruising, leading to less engine wear and tear, a quieter cabin, and improved fuel efficiency. The kit includes a new valve body, wiring harness, and solenoids, with custom TCM tuning tailored for your truck.
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6 Speed Conversion Kit

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Available on iOS & Android

Specifications

BrandDuraMax Tuner
Part NumberD06C DM1361070080900

Videos

Less Road Noise, Better Fuel Economy? The 6 Speed Conversion Kit Is What Your LB7 Or LLY Needs!

Less Road Noise, Better Fuel Economy? The 6 Speed Conversion Kit Is What Your LB7 Or LLY Needs!
I CAN'T BELIEVE THIS DURAMAX 6 SPEED CONVERSION MADE THIS MUCH OF A DIFFERENCE!!

I CAN'T BELIEVE THIS DURAMAX 6 SPEED CONVERSION MADE THIS MUCH OF A DIFFERENCE!!
2005 GMC Sierra 2500HD - Duramax Tuner 6 Speed Conversion

2005 GMC Sierra 2500HD - Duramax Tuner 6 Speed Conversion
We Need An Extra Gear - DIY 'Till I Die Ep. 4

We Need An Extra Gear - DIY 'Till I Die Ep. 4

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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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