[vtirocz]

I only changed the fluid in the transmission (unbolted rear crossmember and supported trans).

As others have stated, the service manual stresses not to overfill the MM6. Here's a quote from the manual:

"IMPORTANT:
Transmission fluid level setting must be followed exactly as written or the
transmission may be overfilled or under filled. For fluid recommendations, Refer to Adhesives, Fluids, Lubricants, and Sealers (MM6)

Transmission fluid level MUST be 3.2 mm (1/8 inch) below (1) the fill plug. This can be done by one of the following methods:

1. Bend mechanics wire to 3.2 mm (1/8 inch) to check fluid level. Add or remove fluid as necessary.
2. Fill transmission until level with the bottom of the fill plug hole, then remove 240 ml (8 ounces) of fluid."

See the attachment in this post called "manual trans flush.pdf": https://www.camaro6.com/forums/showthread.php?t=500494

I also referenced this thread when I did mine: https://www.camaro6.com/forums/showthread.php?t=492814