AOD/ DEM quit today

Blacklab467 · Post by **Blacklab467** » Sat Jan 02, 2021 2:27 pm

I was out today in the deep snow and got stuck this morning in something that shouldn't have gotten me stuck in. Trying to get unstuck revealed that my rear wheels weren't receiving power. I dug the car out and drove home into the garage to check things out and managed to restore operation to my AWD thankfully but didn't find anything conclusive and need some ideas so that this doesn't happen again.
Just a little history on the car: I spent much of the summer reviving the AOD which hadn't worked for about 2 years which involved replacing a dead pump, changing fluid and filter, new Dorman Haldex pump, and welding the collar sleeve to the Bevel Gear input, and cleaning and repacking the propshaft CV joints.......everything has been working flawlessly for about 6 months, no leaks, etc.

Today in the garage after the failure I:
-Jacked the car up, everything looked fine.
-Started the car up, pump appears to not be turning.
-Put 12V to the pump, pump runs fine, reversed polarity and ran the pump the other way for about another 10 seconds.
-Removed DEM connector, I wasn't sure where to find 12V on the pins but poked around and found some voltage between some of the pins. Also measured resistance across the pump at about 1.5 ohms.
-Reseated the #17 CB and measured 4.5 volts there.
-Tested the battery: 12.6Volts.
-Reseated all connectors and put dielectric grease on the pins.

Went for a test drive and confirmed that the AOD works fine again! I'm wondering what happened to cause the failure because I didn't really find anything wrong. Perhaps the Dorman pump is giving trouble? Or a bad connection? Any ideas?

jonesg · Post by **jonesg** » Sun Jan 03, 2021 10:46 am

Vida should show a stored AOC code if it was a dirty connector.

Blacklab467 · Post by **Blacklab467** » Sun Jan 03, 2021 11:13 am

Car did the same thing this morning, I haven't gotten under it to find out why or try and fix it yet. Unfortunately I don't have VIDA.

Blacklab467 · Post by **Blacklab467** » Sun Jan 03, 2021 12:37 pm

Well I think I definitively determined the problem. I put 12 volts to the pump and no life in either direction. That Dorman pump lasted 6 months. I'll order a new Volvo one today and look forward to another day lying under the car

Might as well change the fluid and filter again too.

Post by **erikv11** » Sun Jan 03, 2021 6:14 pm

Wow that is disappointing. I will fix the AWD on the S60 this spring and was going to try out a Dorman, but I don't think so. Thanks for sharing the info.

But the fluid will be pristine now!

Post by **- Pete -** » Mon Jan 04, 2021 11:54 pm

Thank you so much for posting this. This solidifies my suspicions about the non-Volvo AOC/DEM pumps.

I don’t think the Dorman pumps even cost that much less, maybe $50 or so less?

Add this to the “only buy the Volvo part...” list.
There’s just so many of these parts that you just can’t stray away from Volvo for. Told ya!

Edit: you cannot change the pump without fully draining the case. The filter, on the other hand, if the one you put in is the new “finned” version, I’d just leave it be. 6 months of little driving isn’t worth it. Chances are the one you replaced was probably the original.

Blacklab467 · Post by **Blacklab467** » Tue Jan 05, 2021 7:10 am

So true about non OEM.......and yes, you told me so.....again! The Dorman was $167 USD from RockAuto and I paid 390 CDN ($305 USD) for the Volvo pump. I may just leave the filter in as you suggested, we'll see what the fluid looks like. I put the new finned one in after removing the original filter in July.
The first part I changed on this car was the fuel pump when it died 5 years ago and it was an aftermarket brand, now I'm wondering if I shouldn't go fish one out at the wreckers for when it dies next!
I think I jinxed myself when I had nothing to fix on the car and was contemplating treating it to a polish and wax and detail job! It seems whenever you decide to baby a car, that's when it will act up!

Post by **- Pete -** » Tue Jan 05, 2021 8:07 am

Isn’t that the truth! I like to give my P2’s plenty of pillow talk & massaging and it seems like I’m always working on them! It may be time for me to start treating them like an old Ford 7.3 - gallon low on oil & a wash whenever it rains.

Good call on the fuel pump. The pumps seem to last but many have experienced leaks, myself included.

Post by **vtl** » Tue Jan 05, 2021 8:56 am

- Pete - wrote: ↑Tue Jan 05, 2021 8:07 am Isn’t that the truth! I like to give my P2’s plenty of pillow talk & massaging and it seems like I’m always working on them! It may be time for me to start treating them like an old Ford 7.3 - gallon low on oil & a wash whenever it rains.

What? You check oil level in your truck?

=)

Post by **- Pete -** » Tue Jan 05, 2021 9:35 am

vtl wrote: ↑Tue Jan 05, 2021 8:56 am
- Pete - wrote: ↑Tue Jan 05, 2021 8:07 am Isn’t that the truth! I like to give my P2’s plenty of pillow talk & massaging and it seems like I’m always working on them! It may be time for me to start treating them like an old Ford 7.3 - gallon low on oil & a wash whenever it rains.
What? You check oil level in your truck?

=)

When I drain it! If the 5-gallon bucket is ~half full
I know I’m probably ok.

There’s an old saying, “if you can’t see any part numbers on the pieces of metal in the drain pan it’s good to go.”