Transmission Information - Sticky Valves

Transmission Services: Sticky Valves

The risk of sticky transmission valves is real. Taking care of this risk can mean the difference between a transmission that lasts for hundreds of thousands of miles, and one that needs to be replaced within the first 75,000 or so miles.

Here is a look at what Thurston County Transmission does to avoid sticky transmission valves for our customers.

What exactly are sticky transmission valves?

Valves that stick are just what they sound like. It means the valve body has components that are not operating properly because they get stuck during operation.

What are some of the causes and symptoms of sticky transmission valves?

Causes
The most common cause of a sticky valve is poor cooling. High operating temperatures can cause components in the valve body to break down much faster than expected. Extreme heat and carbon deposits cause stickiness among throttle valves, transmission governors or modulator valves on older cars.

Symptoms
If your clutch is in good shape, but your transmission is struggling to move between gears, you may have sticky valves. If a noticable delay of 1 second or more is required between your shifting action and when the gear actually shifts, sticky valves might be the problem.

What steps can a professional mechanic take to prevent sticky transmission valves?

Each transmission shop has a unique approach. Here is our standard service plan to prevent sticky transmission valves:

1. Remove transmission pan drain fluid and inspect pan for evidence of a problem
2. Replace filter or clean screen (most have filters made out of fiber)
3. Clean magnets stuck to bottom of pan
4. Reinstall pan with a new gasket (some use a molded rubber reusable gasket)
5. Refill transmission with correct type of fluid to recommended level
6. Drive to get transmission up to operating temperature and recheck fluid level
7. See manual for checking level in park or neutral at correct temperature
8. For transmissions with no oil pan, remove drain plug and check for an external filter to replace, then refill the transmission fluid.