AWD service Bleeding ATTESA pump system

When I needed to bleed the ATESSA All Wheel Drive system during an overhaul on the Never Ending R32 GTR Epic Build Story, I found a particularly good walk-through on the forums, and from Tyndago's site.  So this is a combination from both. (RBS14 on GTRc and Tyndago)You need Nissan ATF fluid for this application, or any equivalent.
Step 1: Fill the tank 30 mm above MAX line. The tank is located in right rear of your trunk.
AWD Fluid for ATESSA
Step 2: Open the air bleeder on the oil pump. Crack it open until there is no more air coming out and you get fluid dripping. This air bleeder is located on the pump on top of the rear diff. Bleeder is on right side. Can’t miss it.

Rear differential diff bleeder
Step 3: After you tighten up that bleeder go and turn the ignition on. Don’t start the car just turn the key to IGN (Ignition).

Step 4: You need to unclip the air bleeder connector. This is a white clip located under the dash on the right side behind your kick panel" Opposite side of your ECU" Might be a good idea to un screw your kick panel before you do any of these steps. When this connector is unplugged it puts the pump in (air bleeder mode) and the pump operates at a fixed hydro pressure to the transfer actuator
Pump Relay Switch
Step 5: You now need to bleed the nipple on the rear of the trans just below the tail shaft and above the hydraulic line attached to the rear of the transmission. You want to give it 1-second blerps. You can hear the pump actuate while doing this. Do this step until there is no more air coming out the nipple.
AWD pump Bleeder Screw
Step 6: Go back to the tank in the trunk to check the level of fluid. Fill it to max as necessary or just above. Now to finish the bleeding process you need to go back into the car to the air bleeder connector. You want to plug it back in and then unplug it and plug it back in. You want to repeat this process until the lower level fluid in the tank in your trunk has a 5mm max air gap between the lower and higher level fluid. I had to plug in and unplug my bleeder sensor about 20 times at least. If you want get a friend to check the rear level while you sit in the car unplugging the bleeder sensor that might be easier. 


  1. what do you do if u unplug the connector and nothing happens. u never hear the pump come on

  2. @ Anon - Check your fuses, you may have blown the AWD pump fuse in the process... alternatively sometimes it's very quiet and you won't hear it, so you could ask a friend to watch the fluid level in the container, and as you turn it on/off the fluid level should go up and down...

  3. Worked beautifully, great write up! I was able to get the lower fluid level up by just cycling the key on and off in 5 second intervals with the connector still plugged in.

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