Experiencing rough shifts, late shifts, or transmission fluid in your vacuum line on your TH350 or TH400 transmission? The vacuum modulator might be the culprit. This adjustable vacuum modulator from Rostra (part number 44160R, also known as JX67 or 20234) is the fix you need. It comes with a new hose and is designed to precisely control shift points based on engine vacuum, improving performance and smoothness. The adjustable feature lets you fine-tune shifting to match your engine's setup – perfect for stock builds, performance applications, or troubleshooting. Installation is straightforward: just locate the old modulator on the side of your transmission, swap it out, and connect the hose. A fresh modulator can restore crisp, timely shifts and extend the life of your transmission. Whether you're a mechanic, restorer, or transmission enthusiast, this Rostra part is a smart upgrade for your Turbo Hydramatic.