2004 XC70 Driveline Problem

Selkire_AWD · Post by **Selkire_AWD** » 24 Sep 2015, 17:25

When making a sharp turn at very low speed I hear a series of clicks from the rear of vehicle. Trying to find the source of noise, I have car on jack-stands with all four wheels off the ground. If I start the car and put it in gear all wheels turn. With engine off I can turn all 4 wheels by hand. When I crawl under and try to turn driveshaft, it is locked at the front of the rear differential. There are electrical connections and a solenoid at the front of the defferential, so I tried leaving the key on and lever in D, still cannot turn the driveshaft.
Question # 1. Anyone know what the clicking noise is? It's not very loud, just want to make sure it's nothing serious.
Question 2. How do I release the driveshaft so I can rotate it and inspect the center U-joint.

Post by **vtl** » 24 Sep 2015, 18:24

I think clicking you describe is a symptom of a dead Haldex (AOC) pump.

Selkire_AWD · Post by **Selkire_AWD** » 24 Sep 2015, 19:14

Thanks, can you tell me what an AOC pump does? Does this mean my AWD is not working properly?

Post by **vtl** » 24 Sep 2015, 19:21

AOC is a pump, which controls how much of torque is applied to rear differential. Bad AOC pump means AWD is not functioning correctly, or not functioning at all.

This is one of many Haldex replacement threads: http://www.volvoxc.com/forums/showthrea ... D-concerns