ICT Billet Solid Aluminum GM Transmission Mount TH350-4L80E

This is a one-piece, CNC-machined billet aluminum transmission mount that replaces the rubber or polyurethane mount between the tailhousing and the crossmember. Instead of a rubber biscuit that flexes, the whole mount is solid metal, so the back of the transmission stays locked to the crossmember instead of walking around under load.

The fitment list is deep because it uses the common GM mount pattern: TH350, TH400, 700R4, 2004R, 4L60E, 4L65E, 4L70E, 4L80E, 4L85E, 6L80E, 6L90E, Powerglide, and the manual T56 Magnum, TR6060, and Muncie 4-speed. If your car runs one of those and the stock mount bolts to the crossmember, this drops into the same spot.

The reason people switch to a solid mount is deflection. A worn or soft rubber mount lets the tailshaft rise and shift on a hard launch, which changes driveline angle, upsets pinion angle, and shows up as wheel hop or a clunk. Bolting the trans solid to the crossmember takes that movement out, which is why this is a drag strip and heavy-launch part. The trade is honest: a solid mount passes more driveline vibration into the floor than rubber does, so it is a performance choice, not a comfort upgrade for a daily cruiser.

It is machined in Wichita, Kansas from USA-produced aerospace-grade billet, bolts up in the factory location, and does not need the driveshaft or crossmember modified to install. ICT Billet part number 551404.