AAF E46 Rear Diff Fluid Cooler Kit

Why do I need a Diff Cooler?

Rear Diff Cooler kit – Although you may not be tearing up equipment, high heat levels in your differential may be costing you horsepower! As the ring-and-pinion gears mesh, intense heat is generated at the point of contact. Simply pointing an infrared temp gun at the differential cover will tell you the temperature of the cover, but not the real temperatures being reached by the fluid. Preventing diff fluid from overheating is not only beneficial in endurance racing, but in sprint races too.

What makes the E46 Rear Diff Cooler kit by AAF stand above the rest?

The AAF kit is designed to be as close to a bolt-in kit as possible. We have gathered the best parts for the job, and created the best kit out there.

• Fully Automated Electronics

  – One of the best parts of our kit, is that it functions 100% on its own, when it needs to. The leading cause of diffs with coolers installed overheating is that the driver forgets to turn it on. That will NEVER be an issue now! Once the diff fluid comes up to temperature the pump and fan will turn on. Once the fluid has cooled off again, it will shut its self off. A driver operated override switch can be installed in addition to this kit, but is not included (or needed). All electrical parts needed for automated cycling are included.

• Mounting Brackets Included

  – Most kits leave it to you to figure out how to mount the cooler in the trunk. This kit comes with the brackets needed to install the diff cooler in any E46 trunk, and most other trunks!

• Maintenance

  – Changing your diff fluid with a cooler installed can be a drag, but not with the AAF kit. We retain the ability to run the pump while draining and filling the fluid. This ensures that all of the fluid has been pumped out of the diff when draining, and you are able to fill the system completely. When you run the pump during filling the system, you ensure that the pump, cooler, hoses, and differential are full of fluid. This is a huge benefit over other systems that use the fill hole as a return inlet.

• Tilton Pump

  – The Tilton pump we include was designed for pumping oils continuously for up to 1000 hours with no cool down. This is the most robust and dependable pump you can get.

• Fluid Cooler

  – Our huge fluid cooler is the largest of any diff cooler we have seen. Not only does this allow for better cooling, but for increased fluid volume capacity, which helps even more with cooling and longevity of the fluid.

• AN Fittings

  – Not only are AN style fittings the best and most durable fitting to use, we include ALL BLACK fittings with our kit for the BEST look for any color scheme! No more blue and red fittings!

• Push Lock Hose

  – The hose we include is a “Push Lock” style. This is the easiest AN hose to build at home. No more sticking yourself with pesky steel braided hose!

This kit comes with the needed hardware to install a needed fluid return bung into your existing diff fluid cover. If you do not want the hassle of drilling, tapping, and sealing the fitting to the diff cover, simply select the “Include pre-modified diff cover” option!

Why do I need a cover? 

Modifying your cover or buying an already modified cover is necessary for the return of the fluid from the cooler back to the differential. If you do not add the AAF pre-modified cover to your order, be prepared to drill and tap the holes for the fluid return hose.

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