A few months back we detailed the buildup and testing of our street 4L60E trans with help from our trans man Jimmy Galante and parts from Sonnax and TCI Automotive. But that was only half the battle.

PerformaBuilt's all-out 4L60E race transmission starts with OEM parts ... The Sonnax 2.84 Ratio Input Carrier (six-pinion planet) sits inside and splines into the ring gear. See All 26 Photos ...

One of the most common components in today's classic trucks is an overdrive automatic transmission ... controlled transmissions such as the 4L60E and the 4L65E can easily be adapted to street ...

The 4L60E, while a welcome change ... balance," was Pickering's comment about the modifications. Each mod inside the transmission affects something. Increasing pressure and tightening clearances ...