When a transmission starts sucking fluid into the engine, the symptoms are immediate and hard to ignore:

You might notice your transmission fluid levels dropping constantly with no visible leaks on your driveway. 🛠️ How to Diagnose and Fix It

💡 If you’ve just replaced a blown modulator, remember to clean out the vacuum lines. Residual fluid left in the lines can still cause smoke and rough idling for a few miles until it’s fully cleared out.

If you are dealing with a car that "sucks" in the literal, mechanical sense, here is a write-up on why your transmission vacuum modulator might be the culprit. ⚙️ The Mechanics of "The Suck"