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Street Legal TV – TCI Transmission Rebuild

TCI Puts The Fight Back Into Killer Kong’s Worn Out 727 Torqueflite

We think transmissions don’t get the proper credit they deserve. While everybody wants to talk about how many cubic inches, carburetors or how much horsepower your ride’s engine cranks out, very few people bother to ask, “What stall converter you running?” or “How many discs does that clutch have?” Nope; like the Jan Brady of powertrain parts, the transmission will always – and unfairly – live in the shadow of its sexier sibling.

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Since Oldsmobile introduced the Hydra-Matic in 1938, the first American-made clutchless hydraulically-operated transmission (a factory option available for a whopping $57!), Americans have been warming up to the automatic transmission faster than anywhere else in the world. Designed to meet the growing demand from both the daily commuting set and those horsepower-hungry types, the first TorqueFlite came into existence in 1962.

Our TorqueFlite had seen better days. First to go were the old converter, transmission mount (not shown), the kick down lever and gear selector. Next to go was the old oil pan, which when removed, exposed the valve body and filter. The filter screws directly to the valve body, so removing the 10 bolts of the valve body saves you the hassle of unscrewing the four screws keeping the filter on. Since the factory valve body will be replaced with a reverse manual unit from TCI, the old piece was merely thrown away. Finally, all seven bolts holding down the oil pump assembly were unthreaded. The pump – comprised of a pump body, two rotors, and a reaction shaft support – needed to be rebuilt as well.

Built to Last

Surprisingly enough, the sturdy 727 TorqueFlite design survived through the early years of unmerciful “neutral-drop” launches from those racing push-button shifted Chryslers. While such treatment casually murdered one TorqueFlite after another, word quickly spread that the new Mopar slushbox was a force to be reckoned with. Designed to be nowhere near as complicated as GM’s TH350 and 400, and more streamlined than Ford’s C4, the 727 proved formidable behind the HEMI or Mopar’s high-revving LA-block.

But, as it is with most automatics, not all TorqueFlites are the same. Since our project ’69 Dodge Charger Killer Kong was once a mild-mannered two-barrel 383 B-Block-powered daily driver and not a snarling factory-equipped 426 HEMI-powered street bruiser, the included 727 3-speed came woefully ill-equipped to handle the power of a Magnum 440 or a 7-liter elephant – not to mention the 750-horse naturally-aspirated hemispherical-headed monster we’ve got cooking.

Differences between the degrees of performance are various, but usually add up to a discrepancy in the total number of front clutch plates, clutch springs and their respective spring tension, governor weights, the pre-programmed up-shift speed, band friction material and construction, as well as the torque converter stall speed. All of these variants can have a significant impact on the given TorqueFlite’s behavior.

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