TCI 4X and 6X Transmission Packages: Reliable Automatics for Everyone

If there is one thing General Motors knows how to do, it’s building strong, reliable automatic transmissions. The General’s 700R4 and 4L80E automatics are prime examples.

And if there is one thing TCI knows how to do, it’s making those GM transmissions better. With the 4X Four-Speed and 6X Six-Speed Transmission Packages, TCI takes the goodness of the factory transmissions, adds heavy-duty components to handle big horsepower, and puts them into packages for popular GM, Ford, and Chrysler engines.

How is this possible, you ask? It’s kind of simple, really; TCI machined off the factory GM bellhousings, bolted on a universal mounting flange, and made bellhousings to fit these engines:

  • Chevy small block, big block, and LS
  • Ford small block, big block, modular, and Coyote
  • Chrysler small block, big block, and Gen III Hemi
  • Buick, Olds, and Pontiac V8

Interested? Thought you would be. Let’s take a closer look.

4X Four-Speed Transmission Packages

TCI offers two types of 4X transmission packages:

The 700R4-based packages feature a non-electronic 700R4 transmission—no transmission controller required—rated to handle 550 or 750 horsepower. TCI fits the transmissions with a constant-pressure valve body to eliminate low line pressure—a common 700R4 failure point. The packages come with an SFI-spec bellhousing; flexplate drilled for a GM-pattern torque converter; transmission cooler; TV cable; dipstick; and TCI Max-Shift transmission fluid.

The 4L80E-based packages are rated to 875 horsepower and have an electronically-controlled 4L80E transmission that can be used with a factory GM transmission controller or TCI’s EZ-TCU controller. The packages include the SFI-spec bellhousing; a flexplate drilled for a GM-pattern torque converter; transmission cooler; dipstick; and Max-Shift transmission fluid.

6X Six-Speed Transmission Packages

The OEMs have had six-speed automatic transmissions for years, but TCI’s 6X 4L80E Automatic Transmission Package is the first aftermarket six-speed auto that can handle big horsepower—up to 850 horsepower, in fact.

Based on a GM 4L80E, the 6X gives you six forward gears (2.97, 2.31, 1.57, 1.18, 1.00, and 0.75 overdrive) for quicker acceleration and increased fuel economy at cruising speeds. The transmission comes with TCI’s EZ-TCU transmission controller to give you control over shift points. You can get a package with an Outlaw or paddle shifter for full-manual shifting, or no shifter if you prefer. Unlike automatics with an add-on overdrive unit, you can stuff a 6X anywhere a standard 4L80E transmission will fit.

The TCI 6X 4L80E Automatic Transmission Packages include the transmission, bellhousing, and flex plate; EZ-TCU and wiring harness; shifter if selected; dipstick; and transmission cooler. TCI even includes Max-Shift transmission fluid.

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