[oliver77rc]

What happens if torque converter drains back after setting overnight? My truck takes about 10 seconds after starting to move in drive or reverse. When this happens the fluid level is up slightly when checked before starting. I was told by the dealer a check valve in the converter might be bad and it takes a few seconds to pump up. It doesn't happen every time. Could that depend what position the flywheel stops which could allow the converter to drain back. And lastly does this hurt anything.?

 

[Ewag2983]

This sounds like a bad valve body to me.

 

[HemiLonestar]

Converter drainback does not hurt anything, usually thisis a side effect of using aftermarket trans filters. You just need to let it warm up a bit longer to give it a minute to fill the TC back up. FYI you're not supposed to check the trans fluid cold before starting. Supposed to be warmed up to temp and checked hot.

 

[TransEngineer]

The anti-drainback valve is actually a diaphragm in the spin-on (cooler return) filter, inside the trans pan. Did you recently change the filters? Some aftermarket filters have had bad diaphragms.

Drainback does not hurt anything. The air inside the converter (at startup) won't transmit any torque, so that's why it feels like it's slipping. But it really isn't slipping; you're just getting too little torque. The trans will feel like it slowly "oozes" into gear as the converter refills.