P0741 on Cadillac

The CT5 uses GM's 10-speed automatic (10L80) that can exhibit harsh shifts, delayed engagement, and shift hunting, particularly when the adaptive learning resets. The 10-speed has very complex shift logic and can take 500+ miles to fully adapt to a driver's pattern after a battery disconnect, TCM update, or reset. Some CT5 owners report persistent shift quality issues even after adaptation. The CT5-V and CT5-V Blackwing have refined calibrations but can still exhibit occasional harsh shifts.

The CT5 pairs both its 2.0L turbo and 3.0L twin-turbo engines with a GM 10-speed automatic (10L80/10L90), which can develop a torque converter clutch (TCC) shudder felt as a vibration or 'rumble-strip' shake, typically at light throttle and steady cruise (roughly 25-55 mph) when the converter clutch is applying. The accepted root cause is TCC friction-material shedding and fluid contamination degrading TCC apply. GM issued TSB 22-NA-080 covering 10L80/10L90 TCC shudder (added July 2022, later revised to add newer model years). This is distinct from the 10L80/10L90 control-valve-wear recall and from harsh-shift/solenoid codes. Verified: TSB 22-NA-080 exists and covers this transmission family; CT5 use of the 10-speed with both engines is confirmed; CT5/V-Series owner shudder reports are corroborated on forums.

The 4T80-E four-speed used behind the Northstar develops two documented and related faults. The lower control valve body and its channel plate/gasket leak internal pressure, producing 1-2 shift delays, slips and flares with P0731 or P0732, and slipping or complete loss of fourth gear with P0734. Where the pressure loss has been present for a while, the fourth-gear (overdrive) clutch pack cooks off its friction material - owners report finding the pan full of clutch debris and the fourth clutch stripped bare. The transmission fluid pressure switch assembly sets similar codes and is a cheaper first suspect. Owners also report the plastic locating ears on the valve body breaking. Fluid contaminated with clutch material is what carries the failure across the rest of the clutch packs, which is why a late fluid change on a slipping unit often makes it worse rather than better.

GMT800-era Escalades use the 4L60E/4L65E four-speed behind the 6.0L LQ9/LQ4, and in a 5,800-pound SUV the 3-4 clutch pack is the component that gives out. The 3-4 clutch apply circuit runs through a small feed and the waved snap ring and clutch plates cook under sustained load - towing, hills, or just the vehicle's weight over time. It usually starts as a flare or slip on the 2-3 shift, then the transmission stops making 3rd and 4th entirely and drives only in 1st and 2nd (or goes to limp with no movement at all). The sun shell ('Beast' shell) splintering is the other classic failure and produces loss of reverse and 2nd/4th. CarComplaints lists 'Transmission Failure' as the #1 problem on both the 2005 Escalade (avg $2,800 at 79,000 mi) and the 2006 Escalade (avg $2,800 at 77,000 mi), which is early-life failure for a truck transmission. This is a separate failure from the later 8L90 and 10-speed shift-quality complaints.

The GM 6L50 6-speed automatic transmission in V6-equipped STS models is prone to overheating and developing harsh shift quality. The transmission fluid cooler is undersized for the vehicle weight, and the valve body solenoids degrade from heat cycling. Fluid darkens rapidly, and shift quality deteriorates with delayed or slipping 3-4 and 5-6 upshifts. The torque converter clutch also fails prematurely from heat damage.

The Cadillac XT5 uses an 8-speed (2017-2019) or 9-speed (2020+) automatic transmission. The 8-speed shares the torque converter shudder issue with other GM 8-speed vehicles. The 9-speed (GM 9T50/9T65) can have harsh shifts, delayed engagement, and shift hunting. Both transmissions have been subject to multiple software calibration updates from GM. The 9-speed is particularly sensitive to fluid condition and requires proper Dexron HP fluid.

The XT6's GM 9T65 9-speed automatic transmission exhibits shuddering during light throttle acceleration between 25-50 mph, similar to driving over rumble strips. The torque converter clutch wears prematurely, contaminating the transmission fluid.