TV Plunger Spring,200,200C,200-4R,700-4R,4L60,81-93

A low throttle boost condition is a common complaint in vehicles with 700-R4 transmissions. This loss of throttle boost oil creates poor line rise and accelerates 3-4 clutch and band failure. In late-model transmissions, the hardened steel throttle valve continuously oscillates in the cast iron valve body bore and eventually wears the three bore diameters. This wear allows throttle valve feed oil to leak past the valve spool and exhaust, resulting in a low throttle boost condition. This excessive leakage can be eliminated by installing the oversized Sonnax replacement throttle valve 77968.

The three spool diameters on this valve are slightly larger than the late model OEM valve, allowing the valve body bore to be modified to restore the hydraulic integrity of the assembly.
The valve body bore can be made large enough to accept this replacement valve by reaming it with the specially designed reamer 77968-RM, which has three tightly-toleranced cutting diameters that will slightly enlarge the valve body bore in the area of the throttle valve.
Use of reamer eliminates miscalibration or similar wear when exchanging with another used valve body.