Rebuilt 6l80 Fluid Question

[Plimbob]

The summary - I had a local shop rebuild my 6l80 and it now has about 12k on the rebuild. After warming up it tends to shift harder from 1st to 2nd and 2nd to 3rd. However, it is more pronounced up and down between 1st and 2nd. It has done this pretty much from the start, they tell me it is because of the new valves, etc makes the trans shift firmer.

My question, they put in BG trans fluid. I have read on this board and others that the trans shift process is better when the low friction AC Delco fluid is used. I am contemplating having it flushed and have the AC Delco fluid put in to see if it smooths out the shifting.

Any feedback is appreciated.

Thanks
Tim

 

[Fless]

What are the warranty specifics? Is it still under warranty and, if so, are there requirements for fluid changes by the same shop?

 

[swathdiver]

BG does not Dexron VI compatible fluid. Part number 316. Is this what they used on yours or one of the many others?