The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

**Bob B.** · 03-24-2022, 12:36 AM

littlehopper is right. The 6L80 usually has only 5 shift detent positions. P, R, N, D, and M for manual. Some 6L90's in HD trucks have 6 shift detent positions, P, R, N, D, M, and a manual L. These transmissions do not have detents for every gear. I would think any cable shifter designed for a Hydra-Matic ought to work with the addition of a switch to manually select gears when the shifter is in 'M'. Be advised that if you are not doing a complete LS swap with a GM PCM you will need an additions stand-alone TCM for the 6L transmissions, and they run close to $1000. The internal TCM in the 6L valve body is part of the vehicle's CAN-BUS and can't function alone.

03-24-2022, 12:36 AM	#7
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,393	Re: 6L series trans column shift? littlehopper is right. The 6L80 usually has only 5 shift detent positions. P, R, N, D, and M for manual. Some 6L90's in HD trucks have 6 shift detent positions, P, R, N, D, M, and a manual L. These transmissions do not have detents for every gear. I would think any cable shifter designed for a Hydra-Matic ought to work with the addition of a switch to manually select gears when the shifter is in 'M'. Be advised that if you are not doing a complete LS swap with a GM PCM you will need an additions stand-alone TCM for the 6L transmissions, and they run close to $1000. The internal TCM in the 6L valve body is part of the vehicle's CAN-BUS and can't function alone. __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90. Last edited by Bob B.; 03-24-2022 at 12:44 AM.