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Drivetrain› Clutches and Components

American Powertrain

Tremec TKX 5-Speed Transmission Kit

$4,499.00 $4,199.00 Save $300.00

SKU: APO-COGM-F2FX

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INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The American Powertrain Tremec TKX is a 5-speed transmission kit designed for 1970-1974 GM F-Body vehicles. It features a 600 ft-lb constant load rating, a 26-spline input shaft, and 4616 chromoly gears and shafts. The kit includes an aluminum X-Factor cross member with 3.5-inch exhaust clearance, an offset shifter mechanism, and a driveshaft slip yoke.
Show original supplier description
The American Powertrain ProFit TKX transmission kit is engineered for 1970-1974 GM F-Body vehicles, offering a robust solution for upgrading from a 4-speed manual. This 5-speed transmission boasts a 600 ft-lb constant load rating, constructed with 4616 chromoly gears and shafts for durability. It features a 26-spline input shaft and a 31-spline output shaft, with a .68 OD for efficient highway cruising. The transmission is designed for both electronic and mechanical speedometers and fits any GM 4-speed bell housing. The included ProFit installation kit streamlines the conversion process. Key components are the X-Factor modular aluminum crossmember, certified to 1000hp with 3.5-inch exhaust clearance, and the AP Revolution Offset Shifter Mechanism, designed to maintain the OE 4-speed shift position. A 1330 solid yoke, mechanical speedometer conversion adapter, VSS wiring harness, and an ISO-X ballistic mount are also part of the comprehensive kit, along with a white shift knob. This kit requires a 26-spline clutch disc, which is not included. While the main transmission is rated for 600 ft-lbs of torque, an optional TKO Extreme upgrade is available, increasing the rating to 950 ft-lbs with the addition of Cryo treatment and other internal enhancements for high-torque applications.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandAmerican Powertrain
Part NumberAPO-COGM-F2FX
CategoryDrivetrain
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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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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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