Bought a used 2021 Silverado…
Bought a used 2021 Silverado with the 8 speed transmission. Before purchasing I took it out for a test drive, when I returned, I told the salesman that the gear shifting was not smooth and it shuddered. Vehicle had 68K miles, certified used-warranty good to 100K on Powertrain. After owning for 30 days, I tool it to the dealerships service dept., explained the issue, after an 1-1/2 hours repairs were completed.
Steps completed:
1: Drain transmission fluid
2: Drop the pan and filter
3: Inspect & clean exposed components
4: Install new gasket and filter
5: Refill transmission fluid, check fluid level after warming up the engine
*NOTE*
There is no transmission dipstick, GM eliminated it, transmission now has a fill/check plug located on the upper backside of the transmission. Hard to spot, even harder to get at!
Before any of the above service work was performed, the starting battery was disconnected. According to GM, by performing this procedure (min 30 minutes) it resets the TCM (Transmission Control Module)
You can’t make this stuff up!
BTW, my transmission shifts just fine with no shuttering. 😁