A common problem in GM 200-4R and 4L60 transmissions is burned bands and/or 3-4 clutches. This failure can be reduced by eliminating throttle boost oil leaka
Sonnax Oversized Pressure Regulator Valve & Boost Kit - 15741-01K
Sonnax 77917-04K TV Boost Valve Kit .500 Dia., Factory-Style Sleeve (No O-Ring)
Sonnax Boost Valve Kit - 36946-02K
Sonnax TV Boost Valve Kit - 77917-02K
Sonnax Boost Valve Kit - 76990-03K
SONNAX TRANSMISSION & VALVE BODY PARTS & TOOLS
Sonnax 77917-04K TV Boost Valve Kit .500 Dia., Factory-Style Sleeve (No O-Ring)
Sonnax 4L60 (700-R4)
Sonnax Oversized Pressure Regulator & Boost Valve Kit - 104520-07K