Mishimoto Automatic Transmission Oil Cooler Thermostat Mounting Kit

Mishimoto Automatic Transmission Oil Cooler Thermostat Mounting Kits

When automatic transmission fluid runs too hot, the consequences range from sluggish shifting to accelerated wear and, eventually, catastrophic failure. A thermostat mounting kit is the precision link between your transmission oil cooler and the rest of the cooling circuit — and few brands bring as much engineering focus to this problem as Mishimoto.

Automatic transmission oil cooler thermostat mounting kits serve a critical function: they regulate when and how transmission fluid is routed through the cooler, ensuring fluid reaches optimal operating temperature before being directed away. Running fluid through a cooler before it has warmed up can actually cause its own set of problems — delayed warm-up, increased wear, and sluggish hydraulic response. A properly functioning thermostat mounting kit solves this by keeping fluid in the transmission loop until temperatures are right, then opening the circuit to the cooler.

Mishimoto’s Approach to Thermostatic Transmission Cooling

Mishimoto, widely regarded as a world leader in performance cooling products, was established in 2005 and has built two decades of experience delivering superior cooling system upgrades. That deep background in thermal management is evident in how they engineer their thermostat mounting hardware.

Mishimoto’s thermostatic components are CNC-machined from billet 6061 aluminum and are precision-engineered to properly regulate engine oil, transmission fluid, or any other driveline fluid. The included thermostat regulates temperatures at 185°F (85°C), which is easily interchangeable with 160°F (71°C) and 200°F (93°C) thermostat units to accommodate virtually any build. This flexibility means builders can fine-tune their thermal targets rather than accepting a one-size-fits-all solution.

The thermostat includes four -10AN fittings with dowty seals for leak-free line connections, and also incorporates a CNC-machined heat-sink that enhances style while helping to further reduce fluid temperatures.

Mishimoto’s thermal bypass valve kits, such as the MMTC-RAM-TBV, are constructed from CNC-machined billet aluminum with a black anodized finish, and are designed as direct-fit solutions for specific vehicle applications like the 2013–2018 Dodge Ram 2500/3500 6.7L Cummins, with compatibility for transmissions including the 68-RFE and Aisin AS69RC.

Built for the Long Haul

Automatic transmissions generate considerable heat under stress, and while the stock cooling system handles everyday driving well, sustained heavy loads or demanding conditions can push transmission temperatures beyond optimal ranges. Whether you’re towing, off-roading, or pushing a performance build, a Mishimoto thermostat mounting kit ensures your transmission fluid is always managed intelligently — not just cooled blindly.

All Mishimoto products are carefully designed for a clean, direct-stock fit for easy installation and are rigorously tested to ensure quality. Every product is covered by Mishimoto’s Lifetime Warranty, which includes accident protection for cars and trucks. For a category where installation confidence and long-term reliability matter as much as raw performance, that warranty commitment is a meaningful differentiator.

Explore the full Mishimoto brand catalog for their complete lineup of transmission coolers, oil cooler kits, and thermal management solutions, or browse all automatic transmission oil cooler thermostat mounting kits to compare options for your application.