Frequently Asked Questions About Kenworth W900B/W900L Transmission Coolers

Will these transmission coolers fit my specific year and model Kenworth W900B or W900L?

Most aftermarket transmission coolers for W900B/W900L models are designed to fit trucks from 1987 through current production years. However, there can be variations based on your transmission type (Eaton Fuller, Allison, etc.) and whether you have a day cab or sleeper configuration. We recommend checking your transmission model number and confirming the cooler's inlet/outlet sizes match your existing lines. Common sizes are 3/8" and 1/2" NPT fittings. If you're unsure, contact us with your VIN and we'll verify compatibility.

How difficult is the installation process, and what tools will I need?

Installation typically takes 2-4 hours for someone with moderate mechanical experience. You'll need basic hand tools, line wrenches for the fittings, and potentially a drill if new mounting holes are required. The most challenging part is usually routing the transmission lines and ensuring proper clearance from exhaust components. Many drivers report that having a second person helps significantly when positioning the cooler. Make sure to have extra transmission fluid on hand as you'll lose some during the line disconnection process.

What's the difference between aluminum and copper/brass coolers for my application?

Aluminum coolers are lighter weight and offer excellent heat dissipation, making them popular for highway applications. They typically cost less but may be more susceptible to road debris damage. Copper/brass coolers are more durable and better suited for heavy-duty applications or off-road use, though they're heavier and more expensive. For most over-the-road W900 applications, aluminum coolers provide the best balance of performance and value. Consider copper/brass if you frequently haul heavy loads in extreme conditions.

What size transmission cooler do I need for my truck?

Cooler sizing depends on your gross vehicle weight rating (GVWR) and typical load conditions. For standard highway hauling with a W900B/W900L, a 24,000-28,000 BTU cooler is usually sufficient. If you're pulling heavy loads (80,000+ lbs) or operating in mountainous terrain, consider stepping up to a 30,000-40,000 BTU unit. Plate-and-fin style coolers in the 11" x 15" to 11" x 20" range are most common for these trucks. Going too large can actually hurt performance by overcooling your transmission fluid.

Do I need to add an electric fan to my transmission cooler?

Most W900B/W900L applications don't require an electric fan if the cooler is mounted in the airflow path behind the grille. However, you should consider adding a fan if you frequently idle for extended periods, operate in stop-and-go conditions, or have noticed transmission temperatures exceeding 220?F. Fan kits typically add $150-300 to your setup but can significantly extend transmission life in demanding applications. Mount any electric fan as a pusher configuration (in front of the cooler) for best results.