Rear Drive Unit Oil Cooler Installation Instructions

Thank you for ordering our MPP.R Rear Drive Unit Oil Cooler!

Installation is fairly straight forward, but it is critical that you follow the steps to avoid any issues.

Make sure you pre-fill the lines and cooler as instructed to keep the oil level in the drive unit the same as factory.

The Orientation of the hoses and take-off plate is CRITICAL to ensure the fittings can never touch the subframe when the rear of the drive unit moves downwards under load. PAY ATTENTION.

Installation Instructions:

Time Required: 2.5 hours
Tools Required: AN-8 wrench, 1 1/16″ or 27mm Socket, AN-8 plugs, Torque Wrench, Metric Socket set, Spare helper’s hands
Supplies Required: 1L of ATF-9, AN-8 Plug
Difficulty Level: 7/10

Step 1 – Remove Diffuser + Undertray

Jack the car up as high as you can get it, or ideally be on a hoist.
Remove the undertray under the drive unit
Remove the rear diffuser. There are clips behind each rear wheel, as well as bolts. There are also flaps that need to be removed on the rear bumper valence (between the diffuser and the painted rear bumper) that need to be popped open to expose hardware to be removed

Step 2 – Prepare Oil Cooler

Lubricate the o-rings on the Setrab M22 to -8AN fittings and the 90-degree port adapter and install as shown in the photo below. Torque to 40Nm. using a back-up wrench to support the oil cooler core.
Install the 1/8″ NPT temperature sensor adapter on the outside with the port facing rearwards (towards the fan). Tighten.
Install the straight fitting on the short line to the outside port, along with the Setrab 90-degree adapter (see photo for hose details)
Install the 90 degree fitting on the long line to the inside port (see photo for hose details)
Do not yet mount the oil cooler (the picture below is a bit misleading – sorry!)

Step 3 – Install Oil Filter Take-Off Plate

Put a clean drain pan below the oil filter.
Remove the oil filter, and keep track of how much fluid comes out of the drive unit.
Install the MPP oil filter adapter, ensuring the o-ring is properly seated, and the groove and face of the drive unit are clean. Install at the angle showing in the picture.
Thread the central adapter bolt by hand until the o-ring is mostly compressed.

Step 4 – Install Long Hose

With the oil cooler sitting on the ground, or supported by a table, set the long hose out.
Route the long hose over the subframe and connect to the lower port of the oil cooler. See the attached image (pre-production kit shown).
Adjust the rotation of the oil take-off plate so that the line is close to the motor and has ample space to the subframe, keeping in mind that the motor moves down significantly under load.
Torque the 1 1/16″ (27mm) hex to 25lb-ft
Tighten the long hose with the AN-8 wrench.

Step 5 – Fill Cooler And Lines With Oil

The system should now be ready for fluid. Confirm all fittings at the cooler are tight.
We will now use the short hose as the fill port to fill the cooler and lines with oil.
Carefully pour the drive unit fluid into the line. Once you’re nearly full you will need to raise the hose to the same level as the oil filter sandwich plate.
The lines and cooler will take around 600mL of oil.
If you over-fill the system some oil will come out of the sandwich plate, don’t worry it is not possible for it to flow into the drive unit as long as you have installed the hose on the lower fitting on the adapter plate.
Once the lines and cooler are full, cap the line with an AN-8 plug (shown in the picture).

Step 6 – Install Final Oil Line

Pass the shorter line through the subframe as pictured (pre-production hose shown)
With the oil cooler still on the ground or on a table (well below the level of the oil sandwich plate), install the fitting.
Tighten both fittings
Fill the oil-filter with as much oil that had initially drained out, or as much as you can get into it, and install.

Step 7 – Mount Oil Cooler & Hose Cleanup

Mount oil-cooler using the supplied brackets and hardware. No drilling or cutting is required, OEM mounting points are utilized. See picture below as well as the picture from Step 2.
Once the cooler is mounted you may want to loosen and re-orient fittings at the sandwich plate. Ensure enough room is left for the motor’s movement during operation, the motor will move downward over 15mm under hard acceleration.
Re-tighten and check all fittings. Zip tie hoses together as shown in the photo.

Step 8 – System Test

When the drive unit first starts up it will cycle the oil cooler for a few seconds. Have a helper cycle the drive unit power a few times while looking for leaks and confirming that you hear and feel flow through the cooler.
Opening the charge door will turn off the drive unit. Pressing the brake pedal (with the phone or key present) will turn the drive unit on.
Turn the drive unit on and wait 20 seconds until you hear the pump come on. Open the charge door once the pump shuts off.
Repeat this process a few times and inspect for leaks.
You can also force the oil cooler to come on by navigating to a supercharger – if the UI indicates that it is preheating the battery for charging, the oil pump will ramp up to full speed.
Ensure the hoses are not kinked or obstructed in any way. Confirm all fittings are tight.
Remember if a hose comes off or fails the drive unit will empty itself of its oil and catastrophic failure may result. Give the system the respect it deserves!
Inspect the system after your first aggressive drive. Remove the middle tray and inspect the hoses, specifically around the subframe, for abrasion or wear.

Step 9 – Fan Wiring

Ground the negative terminal of the fan to chassis ground.
Using best practices (NOT WIRE TAPS!), splice an 18AWG wire to the amplifier’s power lead. This is a 12 AWG Red wire in pin 6 of connector X561.
The amplifier is located behind the carpet on the right side of the trunk carpet.
You can use a high current switch or our Solid State relay and a microcontroller or low current switch to control the fan. Please contact us if you’d like to purchase a Solid State Relay to connect your fan that way.
The oil cooler’s cooling output is almost negligible with the fan off, so the fan must be running to have effective cooling!
Re-install the diffuser and drive unit tray and go enjoy!

Step 10 – Trim Rear Valence

The oil cooler can be run either with the plastic rear valence removed, or you can make a cutout in the rear valence to allow airflow to exit. The picture below gives an idea of the shape and area to cut (see the blue area).