Solution for Problematic GM Transmission
The 8-speed GM automatic transmission has
already caused a lot of troubles for the automaker because of some technical
issues. In April 2019, transmission issues eventually led to the court action
against GM, in which car owners complained about numerous transmission problems
and demanded it to be eliminated. Now it seems like GM has found an efficient
solution for issues related to the 8-speed unit.
Recently, the automaker started using a new
type of Mobil 1 ATF for this problematic transmission. Now, customers, who are
not satisfied with operational capacities of the mentioned gearbox unit, are
advised to perform ATF flushing. GM dealerships are also instructed to perform
flushing services on all possibly affected new cars.
Mobil
1 Synthetic LV ATF HP fluid
The TSB document says that the new solution deals with torque converter clutch (TCC) shuddering issues detected on 8L45 and 8L90 units. The list of affected brands includes the following:
These transmission malfunctions have a dual nature. Firstly, some customers complain about frequent gearbox vibrations. Secondly, shifts between 1-st and 2 gears are very harsh. These problems manifest themselves in the most vivid way under light and medium throttle applications, and as often during full throttle applications. It seems like ATF flushing really helps to solve the issues, as many customers have confirmed significant improvements in gear shifting quality after ATF change. In cases when ATF flushing amounts to nothing, then GM experts recommend to replace the torque converter, which could be badly affected.
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GM
8L45
The issue can be caused by the fact that moisture may get mixed up with ATF. Therefore, the old ATF must be changed with a new ATF. After driving the car for several days, owners should notice improvements in gear shift quality, as the new ATF cleans the gearbox internals and the adaptive shift algorithms relearn various parameters. Problems with 8L45 and 8L90 units undoubtedly caused a lot of troubles to the owners of affected cars and the new fluid swap can become a long-term solution.
