TCI Maximizer 4×4 Transmissions 371400

Lift kits and oversized tires put extra strain on a drivetrain, and this remanufactured four-speed automatic is sized for exactly that kind of four-wheel-drive demand rather than light-duty street service, running the Chevy bellhousing pattern, a forward shift pattern, and lockup compatibility.

Why it's built heavier

The internals in this line are sized up specifically to handle the extra load that comes with aftermarket suspension lifts and larger-than-stock tires, which puts more strain on a transmission than stock-height street driving does. First gear sits at 3.06:1, the input end carries 30 splines, and the case is aluminum with a stock-profile pan. It is lockup compatible, a feature not every automatic in this catalog shares, which matters if your controller or wiring is already set up to use it.

What's missing from the box

Treat this as transmission-only: a converter, flexplate, controller, and harness all need to come from somewhere else, along with the cooler and fluid. It also doesn't include a shift lever. If you're swapping out an identical model, your existing speedometer gear and its housing should bolt right back on, since neither ships new with this unit. Sold individually.

Is this suited to a lifted truck with big tires? Yes, the internals are built for that added demand. Does it come with a shift lever? No, that needs to be sourced on its own.