Drivetrain› Automatic Transmissions and Components

TCI Automotive

TH400 HD STEEL MAIN SHAFT

$1,070.50

SKU: T00M 223700

In Stock
In Stock
Ships by Jun 8
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Non-Returnable Item
INSTALL DIFFICULTY
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Advanced — 4+ hours

Description

The TCI Automotive 223700 is a heavy-duty billet main shaft for TH400 automatic transmissions, made from 300M alloy steel for high-performance applications. It is an internal upgrade for any TH400 transmission, commonly found in GM vehicles from the mid-1960s to early 1990s.

Fitment

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Specifications

BrandTCI Automotive
Part NumberT00M 223700

Buy with Confidence

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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