21 GMC sierra AT4 6.2 shudder/vibration after trans flush

[DonnyAT422]

Recently took my AT4 in to service for the standard 45k service. At this time it’s recommended to do a flush, so we proceed to keep service Records up to date.
 

After about a week after the flush, I started to notice an increase in the shudder at 30-40 mph. It was alway noticeable coming to a stop prior the flush. Now it feels like a rumble in the steering wheel. A hesitant response feel, but once I step on the gas - I gain mph. 
 

I had my truck in for diagnostic around 28k to get my concerns recorded. For the most part I dealt with it and lived with the slight rumblings at stop. But after the flush, it seems worse. Am I going crazy, or is this a sign of something deeper to come?  I’m 10k from warranty going, so trying to get in front of it. 
 

 

[Tom73]

Take a look at this thread, 

Your issue sounds a lot like a valve body issue. Mine went out after transmission service. No indication of problems before the service. 

 

[DonnyAT422]

Thanks. Weird it becomes more apparent after the service.