TRANSFER OF POWER.

GM Powerglide, Turbo-Hydramatic 350s and 400s, Ford C4s and C6s, Chrysler TorqueFlite, Tremecs, Toploaders, and T5s — the gearbox, or transmission, is something that is somewhat the unsung hero of your driveline. It typically gets the least love, and, ironically, it’s also the part that can make or break the performance of a combination. Perhaps it’s the complexity of the automatic, the mind-bending science behind correct converter selection, or the simplicity of the driveshaft, but we all tend to never give it a second thought until something goes wrong. Upgraded power plants are great, but have you put into enough thought into selection and modifications to handle that power?

TORQUE CONVERTERS

In a manual gearbox, you’ll have a clutch, but in an automatic it’s the job of the torque converter to both engage and disengage the engine from the driveline, which it does with fluid. How does that work? A centrifugal pump (impeller) uses the engine’s rotation to send fluid outwards; this in turn causes a vacuum that pulls new fluid into the middle of the converter. The drive happens when this pressurised fluid is forced through the blades of the turbine. The turbine is not mechanically connected to the engine; it is, however, connected to the transmission through its splined shaft. The fluid hits the angled blades of the turbine, which are in the opposite direction to those of the impeller. This action spins the turbine blades and in turn provides drive for your transmission. The harder you rev, the higher the pressure