No Engine Braking In 2nd Speed

THM 3L80 & 3L80HD (400 & 475) transmissions contain a plastic front accumulator piston, if broken or cracked, can cause a no engine braking in drive 2 (D2) condition. The piston should be replaced with an aluminum front accumulator piston, part number 8626883.

1. Front servo or accumulator oil rings leaking.
2. Front band broken or burned.
3. Front band not engaged on anchor pin and/or servo pin.