The Mishimoto thermal bypass valve kit replaces the failure-prone factory bypass valve on the ZF 8HP transmission in the Jeep Grand Cherokee, Grand Cherokee L, and Dodge Durango. The stock valve withholds transmission fluid from the cooler until operating temperature, but its thermostat can fail closed — starving the cooler and overheating the transmission. This CNC-machined billet aluminum valve includes a fully serviceable thermostat for fast cold-climate warm-up, plus an installable thermostat-bypass insert for constant cooling in hot climates or heavy towing. Strategically machined internal passages improve flow over stock, and cooling fins machined into the body add heat dissipation. Black anodized, installs in under an hour.
| Brand | Mishimoto |
| Type | Transmission thermal bypass valve kit (thermostatic) |
| Transmission | ZF 8HP |
| Material | CNC-machined billet aluminum, black anodized |
| Thermostat | Serviceable, with installable full-bypass insert |
| Install | Under 1 hour |
| Warranty | Mishimoto Lifetime Warranty |
This part fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2018-2024 | Dodge | Durango | Citadel / GT / R/T / SRT / SRT 392 (all trims) |
| 2016-2020 | Jeep | Grand Cherokee | Laredo / Limited / Overland / Summit / SRT / Trailhawk (all trims) |
| 2018-2021 | Jeep | Grand Cherokee | Trackhawk / High Altitude / Limited X |
| 2021 | Jeep | Grand Cherokee L | Laredo / Limited / Overland / Summit (all trims) |
