1981 to 1993 General Motors vehicles equipped with the TH200-4R, TH700-R4 and 4L60 automatic transmission were fitted with various diameter boost valves from the OE manufacturer.
The diameter of these valves is based on the specific vehicle application, such as engine size, chassis weight, etc., As the years have gone by, these transmissions have been exchanged and overhauled many times over. As a result, the transmission may have the incorrect diameter boost valves for the given application. Consequently, if the wrong diameter boost valve is installed, shifts will be soft or flared and the unit will experience repeated friction element failure due to inadequate line pressure.
|#7-300||Low and reverse boost valve and bushing for firmer manual 1-2 shift|
|#7-422||.422″ TV boost valve and bushing recommended for light duty V6 and V8 gas engines|
|#7-472||.472″ TV boost valve and bushing provides faster line pressure response and higher max line pressure for heavy duty towing, off road, and mild performance use|
|#7-500||.500” TV boost valve and bushing. Ideal for big block competition, racing and pro-street|
What is a boost valve ?
The TV boost valve influences line pressure in accordance to the throttle valve pressure cable stroke. The low-int/reverse boost valve provides a static pressure increase as well as determining the fixed line pressure value in manual 2nd and 1st ranges. Adequate main line pressure is required to provide enough clamping force under all load conditions to prevent slipping, as well as to achieve proper shift quality. Consequently, incorrect diameter boost valves will cause complaints of soft shifts, flare shifts and burnt friction elements.
Features and benefits:
These TransGo replacement boost valve and bushing assemblies provides you with an economical and durable direct replacement for the OEM assembly.
- Insufficient line rise
- Soft, slipping or flaring shifts
- Burned friction material