• An empty cart

    You have no item in your shopping cart

AAF E46 Diff Fluid Cooler Kit


AAF E46 Diff Fluid Cooler Kit


  Clear selection


Why do I need a Diff Cooler?

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 AAF Kit 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!

Additional information

Weight N/A
Dimensions N/A



There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

Make Model Year
Make Model Year
BMW 318 1999
BMW 318 2000
BMW 318 2001
BMW 318 2002
BMW 318 2003
BMW 318 2004
BMW 318 2005
BMW 318 2006
BMW 320 1999
BMW 320 2000
BMW 320 2001
BMW 320 2002
BMW 320 2003
BMW 320 2004
BMW 320 2005
BMW 320 2006
BMW 323 1999
BMW 323 2000
BMW 323 2001
BMW 323 2002
BMW 323 2003
BMW 323 2004
BMW 323 2005
BMW 323 2006
BMW 325 1999
BMW 325 2000
BMW 325 2001
BMW 325 2002
BMW 325 2003
BMW 325 2004
BMW 325 2005
BMW 325 2006
BMW 330 1999
BMW 330 2000
BMW 330 2001
BMW 330 2002
BMW 330 2003
BMW 330 2004
BMW 330 2005
BMW 330 2006


Lost your password?