I have been battling a very aggressive 1-2 shift after having my transmission rebuilt. The car drives and performs perfect otherwise, I just really don’t like the 1-2 shift. After doing my own research I found this part by SONNAX and it cured my shifting issues. I believe this also applies for other transmissions as well: 200-4R, 4L60, 4L60-E, 4L65-E, 4L70-E

Sonnax 77998-03K Transmission Kit, 1-2 OR 3-4 Accumulator Piston (.310" Pin)

LINK
https://www.ebay.com/itm/124327786449

- PER SELLER ON EBAY -
Symptoms:

Poor shift quality
Burnt clutches & bands
Cause:

Wear at the piston pin bore due to repeated reciprocation.
Correction:

The Sonnax patented pinless design with dual seals stabilizes the piston in the bore and provides improved sealing characteristics. Use of the Sonnax part eliminates the need for the pins.
200-4R, 4L60, 4L60-E, 4L65-E, 4L70-E
Pinless Accumulator Piston Kit
Part No. 77998-03K