Volvo Haldex AWD Coupling Oil Pump, OE 31256757

When an all-wheel-drive Volvo S60, S80, V70, XC60, XC70 or XC90 starts spinning its front tires on wet roads or snow, shows an AWD service message, or simply feels like a front-driver, the electric oil pump on the Haldex rear coupling is the usual culprit. This pump replaces Volvo OE 31256757 and interchanges with Dorman 699-005. It is the charge pump for the fourth-generation Haldex coupling, and the listing also covers earlier S60 and V70 AWD cars from chassis 495001 on.

What the Haldex pump does on an AWD Volvo

The Haldex coupling sits in the driveline just ahead of the rear differential. Inside is a wet multi-plate clutch, and it is open by default: the rear axle only gets torque when oil pressure clamps that clutch pack. On the Gen 4 design the electric pump is what builds that pressure, and the AWD control module then meters it through a valve to decide how much torque goes rearward. The pump draws oil through a screen at its inlet, and that same oil lubricates and cools the clutch plates. Fine clutch wear material collects in the oil over the years, loads up the screen and filter, and the pump motor overheats trying to pull through it. Once the pump stops, the coupling stays open and the car is front-wheel drive only.

Symptoms of a failing Haldex pump

• Front wheels spin when pulling away on rain, gravel or snow, with no push from the rear
• An AWD service message on the instrument cluster
• A pump or coupling fault stored in the AWD control module while the engine and transmission show nothing
• No faint pump hum under the car when the engine is first started (a healthy pump can often be heard priming)
• Black, sludgy oil when the coupling is opened up

How to confirm it before you order

A generic engine-code reader will not see this fault, because it lives in the AWD module. Use a scan tool that reaches chassis modules on Volvo, such as the Autel MaxiCOM MK808S, and read stored codes and live data. Our scan tool buying guide compares what each class of tool can reach, and reading live data covers how to watch a value change while you test. Next, check power and ground at the pump connector; a broken wire or corroded plug can mimic a dead pump. If the pump gets voltage, the screen is clean and the rear still never engages on a slippery surface, the pump is the likely failure. If the pump runs but the rear still will not drive, the coupling clutch pack or its control valve may be the problem instead.

Fitment

The listing covers AWD versions of the Volvo S60 2003-2009 and 2011-2012, S80 2009-2012, V70 2003-2007, XC60 2010-2012, XC70 2009-2012 and XC90 2009-2014. On the S60 and V70 it applies from chassis number 495001 onward only; earlier cars of the same year use a different coupling pump. Front-drive cars have no Haldex unit. Because the same fourth-generation coupling family was shared with other makers, compare the number on your old pump to 31256757, or send us your year and VIN and we will confirm before it ships. Related driveline and transmission parts are listed in our hard parts category.

Install notes

• Raise and support the car and find the pump on the side of the coupling housing ahead of the rear differential. On some models, the XC90 in particular, the propshaft has to come down for clear access to the coupling.
• Unplug the connector, remove the two retaining bolts and pull the pump straight out. Old oil will drain, so have a pan ready.
• Clean the inlet screen area and the bore, then fit the new pump with fresh O-rings lightly coated in Haldex oil.
• Change the coupling oil and filter in the same job. Contaminated oil is what kills these pumps, and a new pump fed through a loaded filter will not last.
• Refill with the specified Haldex coupling oil through the fill plug. A small hand pump such as the 3L manual fill pump reaches the side port more easily than a bottle.
• Clear the AWD codes, then road test on a low-traction surface to confirm the rear axle pulls. If the car also flares between shifts, the 2003-2009 S60 and V70 AWD automatic is often the AW55-50SN; our AW55-50SN service guide covers that unit separately.

Will this fit my 2005 Volvo S60 AWD?

Only if the car is from chassis number 495001 onward. Earlier S60 and V70 AWD cars use a different coupling pump. Check the chassis number, or send us the VIN and we will confirm.

Is this a Gen 4 Haldex pump?

Yes. 31256757 is the fourth-generation Haldex charge pump used on AWD Volvos, and it interchanges with Dorman 699-005.

Should I change the Haldex oil and filter when I replace the pump?

Yes. A clogged filter and dirty oil are the most common reason these pumps fail. One maker of a Gen 4 service kit recommends changing the coupling oil and filter every 30,000 miles or 3 years.

Can a bad Haldex pump damage the transmission?

Not directly. The car simply runs in front-wheel drive. Constant front wheelspin is hard on tires and the front driveline, so it is worth repairing promptly.

Do I need a scan tool after installing it?

Yes, to clear the stored AWD fault and confirm the module sees the pump working. A basic engine-code reader will not reach the AWD module.

• Best Scan Tools for a Transmission Shop
• How to Read Transmission Live Data
• Aisin AW55-50SN Service Guide