Sun Coast A1-6VB-TCM-LB7 Allison 5-6 Speed Conversion

2001-2004 GM 6.6L Duramax LB7
Sun Coast Converters
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The Sun Coast A1-6VB-TCM-LB7 Allison 5-6 Speed Conversion for your 2001-2004 GM 6.6L Duramax LB7 converts your 5-Speed Allison A1000 Transmission into a 6-Speed like the later models. With the conversion, you can drop 325 engine rpm @ 75 mph with 3.73 gears. While increasing fuel economy 1 – 1.5 MPG, reduces engine noise while cruising, a truck with 3.73 gears that normally likes cruising at 62 MPH will now cruise nice at 72 MPH. The gear ratio in your 5 speed is .71 and our 6th gear will be .61. 6th gear can be disabled with your two haul button and 5th canceled with OD off. Requires valve body and TCM change. No wiring, no modifications required.


  • Converts 5-Speed Automatic To 6-Speed
  • Decrease Cruising RPM's
  • No Wiring, No Modifications Required
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(2 Ratings, 1 Review) Average Rating:
Nice cruising with an extra gear on the highway.
Chris ( NJ) 4/6/2017 8:41 PM
I've had this conversion since 2011. It is great for highway cruising and something the LB7 owners would love, but find it hard to spend the money to drop 300rpm and get maybe 1 MPG more or not. The truck definitely shifted better and more crisp and has the torque to cruise at a nice speed and not feel like you're pushing the engine that hard. The main reason why I am reviewing this is that I wanted to installed a Trango junior kit recently (2017). I purchased the(6 speed) junior kit, dropped the valve body and discovered that in fact the conversion valve body already had the kit installed in it from Suncoast. So I wasted 80 bucks on a kit that was already installed and it is not listed int the description. Just wanted to inform any buyers not to waste their money on the Junior kit. Maybe inquire to see if they install that kit standard in all conversions to be sure.