A worn valve or valve body bore can result in incorrect pressures in the transmission, which may lead to poor performance or failure of the transmission. With the proper equipment, vacuum testing is an efficient way to determine if a valve/bore is worn or to verify if a valve repair was performed correctly. It’s an easy diagnostic technique that yields repeatable, numerical results for comparison and documentation.

Sonnax vacuum test plate kit 34994-VTP for GM 4L80-E and 4L85-E units is an ideal tool for fast, easy testing. The plate and seal fit securely over the entire valve body casting to seal all the critical valve body passages at once. Strategically located test ports and exhaust holes allow all key casting areas to be vacuum tested quickly by just moving the vacuum test tip.

• Clear test plate and silicone pad seal casting for quick, easy testing
• Open ports at key areas identify recommended test locations
• Easy-to-follow instruction booklet identifies ports, valves, symptoms of wear and the right Sonnax parts for repair