spn 2791 fmi 7 a26
Discussion Starter · #1 · Sep 30, 2015. Ugh so here we go, starting yesterday my truck started shuddering at 45-55mph under slight throttle input speeding up very slowly and then maintaining a constant speed when the TCC is locked up. It happens in 3rd gear under lockup and same as 4th gear, adding throttle and the converter unlocks and all. The 8-Speed GM Transmission. The GM 8L90 and 8L45 transmissions were developed to replace earlier 6-speed automatic transmissions in General Motors rear wheel drive vehicles. The 8L90 was introduced in 2014 in vehicles like the Chevrolet Silverado / GMC Sierra pickups, the GMC Denali, the Corvette and Camaro, and several Cadillac applications. GM 6L80/90, 8L90, & 10L90 Transmission Shudder During Acceleration General Motors has released technical guidance regarding a shudder issue caused by improper transmission fluids in their 6L90, 8L90 and 10L90 transmissions. These transmissions suffer from torque converter clutch shudder during acceleration between 25 - 80 mph.