1981 GMC K1500 Transmission Shift Kits

A B&M transmission in a box! Transform your automatic transmission into a full-tilt B&M performer! This is our ultimate transmission kit – it comes complete with full instructions on how to assemble your transmission to B&M specifications.

These kits include all of the necessary components to rebuild your automatic transmission. OEM style gaskets included. Kits do not include overhaul instructions – please refer to factory shop manual for proper assembly procedures.

The B&M Transpak is the next step up from the B&M Shift Improver kit. It has all the features in the Shift Improver kit, plus it provides additional driver manual control (GM TH-400, 350, Ford C-6 and Chrysler Torqueflite only). B&M Transpak kit for 1968-1981 GM TH350 automatic transmissions. Most stock automatic transmissions won’t downshift into low gear above 15 mph, and automatically upshift at a predetermined speed no matter what gear you’re in. With the Transpak, you can downshift at any speed, and you can hold the transmission in first gear to any speed that you want! This is an asset when you’ve got a modified engine, and you want additional RPMs, or you’re towing a trailer or driving heavy loads downhill. Stage 1. Heavy Duty is for street rods, normal passenger vehicles or other heavy duty use. Firmer shift feel but not harsh. Improves transmission performance and life dramatically without loss of comfort and offers normal automatic operation when in Drive. Stage 2 is for Hi-Performance street use. Essentially the same as Heavy Duty mode except shifts are much quicker. Retains full automatic features and standard shift points with selector in Drive. Notes: Does Not Fit GM TH350C transmissions.

ATP Transmission Components are exact fit, no compromise replacement parts

The B&M Shift Improver kits feature two options to recalibrating your 1965-1987 GM TH400, TH375 and TH475 automatic transmissions. First is the HEAVY DUTY set-up, giving you firm positive shifts without loss of driver comfort for improved performance in all street vehicles. This is a great option for performance street driving or towing. The second is our STREET/STRIP set-up. Be warned, this will deliver firm positive shifts you will feel, along with easily chirping the tires when shifting somewhat aggressively. This setting is recommend for high performance street/strip use, or for competitive events when you want the hardest, quickest shifts possible from a shift improver kit.

The B&M Shift Improver kits feature two options to recalibrating your 1968-1981 GM TH350 automatic transmissions. First is the HEAVY DUTY set-up, giving you firm positive shifts without loss of driver comfort for improved performance in all street vehicles. This is a great option for performance street driving or towing. The second is our STREET/STRIP set-up. Be warned, this will deliver firm positive shifts you will feel, along with easily chirping the tires when shifting somewhat aggressively. This setting is recommend for high performance street/strip use, or for competitive events when you want the hardest, quickest shifts possible from a shift improver kit. Note: Does not fit GM TH350C with lock-up. Use part# 30235 for TH350C transmissions.