Randy Daggett

I have been rebuilding transmissions for over 30 years and I just bought at the time a new 2020 Chevy Silverado 5.3L and I love it except for all of the little features that I really didn’t want but anyway let’s get to the 8 speed Chevy transmission, I have found that most of the time when the transmission is clunking or shifting hard at lower speeds is due to a faulty Valve body and THECM unit, or internal clutch packs that are leaking or just burnt clutches can cause clunking at low speed, the valve body is one of the most common reasons for clunking at low speed, but there can be burnt clutches or a defective one way clutch assembly, pump assembly not producing the correct pressures. When ever I rebuild a newer 6,8,10 speed automatic transmission I always get a remanufactured Sonnax valve body, they are all dyno tested for internal leaks that cause clunking and many other issues!