'07 S60 AWD Concern

soulvoid21 · Post by **soulvoid21** » 23 Feb 2021, 07:58

Hello,

I own a '07 S60 2.5T AWD. Currently has 166k miles on the body, 115k on the engine, and unknown mileage on the trans (around 100k) as it was swapped with a junk yard unit.

However, I'm concerned my AWD is not performing correctly. No warning lights on the dash, stored codes or pending codes, but last night trying to back into my driveway through 1-2in of snow, the car was just sitting still with both front tires spinning. I have very good snow tires on the vehicle all around as well. I moved forward about 6 inches onto dry pavement, and had no issues backing in from there. It was not deep snow, rather well packed, icy, speed bump sized mound. But the back tires should have had traction where they were positioned.

I know the AWD works, because if I'm spinning the rear wheels do provide some power when moving forward, and will spin if I throttle down hard enough. Additionally, if I accelerate from a stop a bit hard and the front end breaks look, I can feel the AWD hook up pretty hard. But it just doesn't feel right when I'm in snow. The front end constantly slides around while the DTSC fights the slide (or if I turn DTSC off and feather the throttle).

Am I expecting too much out of the AWD? Are maybe my brake pads worn a little too far, causing the DTSC to not do its job? Pads are older but still have a good amount left. This happens with DTSC on or off, and in Winter mode.

I'm unsure when the AWD was last serviced by the previous owner, so it's possible the fluid is expired. But I'd think that would cause it to not hookup at all, on a dry surfaces especially. Angle gear is fine, no leaks, play or anything of that sort as well, and the car performs amazingly otherwise.

Thanks for any insight!

Post by **Blacklab467** » 23 Feb 2021, 11:19

It sounds like your AWD isn't working. The front tires shouldn't spin more than 15 degrees before the Haldex sends power to the back . You noted that you "know" the AWD works because when the front tires are spinning you do get some power to the rear, this is somewhat encouraging. It suggests that the front components, namely the bevel gear and associated collar sleeve are functional. It also suggests that the Haldex, differential and DEM are working properly.
I would be about 99% sure based on what you have described that the Pump and fluid/filter are the cause. These pumps don't last forever, and can fail or weaken intermittently, as you'll find well documented in posts on this forum. Also dirty fluid and contaminated filter may reduce flow/ pressure, impeding Haldex operation even with a good pump.
I would suggest a new pump , upgraded filter and new fluid. You could try and just change the fluid and filter but the amount of miles your car has, the pump is almost certainly on its way out. You only want to remove the propshaft once, trust me!
Get a Volvo brand Haldex pump......trust me on this one too.

soulvoid21 · Post by **soulvoid21** » 23 Feb 2021, 12:30

Blacklab467 wrote: ↑23 Feb 2021, 11:19 It sounds like your AWD isn't working. The front tires shouldn't spin more than 15 degrees before the Haldex sends power to the back . You noted that you "know" the AWD works because when the front tires are spinning you do get some power to the rear, this is somewhat encouraging. It suggests that the front components, namely the bevel gear and associated collar sleeve are functional. It also suggests that the Haldex, differential and DEM are working properly.
I would be about 99% sure based on what you have described that the Pump and fluid/filter are the cause. These pumps don't last forever, and can fail or weaken intermittently, as you'll find well documented in posts on this forum. Also dirty fluid and contaminated filter may reduce flow/ pressure, impeding Haldex operation even with a good pump.
I would suggest a new pump , upgraded filter and new fluid. You could try and just change the fluid and filter but the amount of miles your car has, the pump is almost certainly on its way out. You only want to remove the propshaft once, trust me!
Get a Volvo brand Haldex pump......trust me on this one too.

Thanks for the reply! At least I know my thought process is correct! I wouldn't be surprised if the fluid is completely past it due date. I've never changed the fluid myself and have put 66k miles on the car. No idea when it was last, if ever, serviced. So it's definitely long over due.

The system is indeed working. I've gotten the car stuck many times in deep snow, to the point that all 4 tires were floating. The times that happened, I could open the door and look back, and see the rear wheels spinning. However, it still seemed like the front wheels were getting way more power/spinning significantly faster than the rears. And from what I've read (I could be mistaken) this system should split power about 70/30.

This seems like a DIY job that I can tackle in my garage, so I'll give it a go. My regular service light just came on today, so it looks like I've got some other work ahead of me anyway.

I'll definitely report back if I still have issues, or if this fixes it. You guys have never let me down before, so I'm sure we'll get it sorted!

Post by **erikv11** » 23 Feb 2021, 12:45

Is the AWD even supposed to engage in reverse, does anyone know?

Post by **- Pete -** » 23 Feb 2021, 12:51

Yes, AWD does engage in reverse.

At the end of the DEM/Haldex’ pump life the AWD can certainly work only intermittently. So you may have witnessed it beginning to get flakey.

A rudimentary test to see if your DEM pump/module is operational is to press and hold the “read” button on the end of the turn signal stalk while simultaneously pressing twice (2X) the REAR fog light button. Then scroll through the DIM screen by pressing “read”, cycling through all the readable modules in the car until you get to DEM. It should report the status as “ready”.

On one of my AWD P2’s the DEM pump went about 272,000 miles before it finally quit. I have another AWD V70 that is at 148,000 and it is showing the beginning signs of DEM pump failure. Just illustrating that it can affect these cars at a wide range of miles.
As far as the power split goes it doesn’t translate into fronts spinning at a different rate of speed than the rears. Rather, it’s how much power is being sent to the front vs rear. And you’re correct, it is front biased. But on glare ice, if all 4 were broken loose they would all spin at around the same speed.