AWD Maintence: Part 1

[sasmith]

This is my first post on the forum but I would not still be driving my 05FS AWD if this site did not exist. Had to give up on my local Ford house years ago. My FS is at 225k and has experienced most of the common problems but overall this thing has been very dependable. My AWD quit functioning 4 years ago and as you all know, at that time the DEM options were expensive and very limited. Replaced the solenoid sending switch at that time but did not fix it. Since then, I have been driving the vehicle with AWD dysfunction light on with no issues yet but all the electronics and driveline still hooked up. My question is, what would be more practical at this time. Have the DEM fixed or just convert this thing to AWD. What potential problems would I encounter if after all these years I sent the DEM off for repair? If I decided to convert to FWD, what exactly would it take to do this?

[Jack Watts]

Welcome to the forum!

First things first, how do you know it's the DEM? Have you eliminated the pump as a source of trouble? The Haldex pump ends up being the root cause about 90% of the time.

As far as fixing it vs. converting it, I guess it depends on whether or not you need the AWD? The components should be fine, you'd just want to change all of the fluids (front PTU, rear differential, Haldex fluid, filter and probably the pump (or remove and clean the pump if the DEM is in fact the problem). Do that, and it should be up and running.

To turn it to FWD permanently, you can pull just the driveshaft (which will probably save you 1-1.5mpg, or you can go full-on and remove the DS, rear diff/haldex unit and rear axles. That should give you 2-2.5mpg boost, since you eliminate some rolling losses, drivetrain losses and a significant amount of weight. You may need to drop part of the rear subframe to get the rear differential assembly out, but I'm not sure. I can check in the service manual at some point if you'd like.

I've been maintaining the fluids in mine pretty religiously, but the day I have AWD issues I'm pulling everything out. I'd rather have the mpg boost, and FWD+snow tires probably beats AWD and all seasons anyway. The AWD has served me well and all, but in reality I don't need it very often.

[sasmith]

Thanks for the reply. Actually not sure it is the DEM. Pulled the code 4 years ago, replaced the solenoid switch, then just gave up thinking that there is no way this vehicle would last long enough to justify the cost of the new DEM (which the dealer said needed replacing) I soon figured out that I knew more than the local Ford service center so have just been playing a waiting game. And the vehicle just keeps driving...so I thought what the heck, I will just go ahead and fix it. Checking the pump tomorrow. After reviewing your detailed posts, I now feel confident I can get the AWD back and running. Honestly, when the AWD was working, it was the most impressive AWD I had ever driven. Thanks again. This forum and your detailed posts have already saved me thousands over the last few years. Fluids and filter are already on order. Will post the outcome.

[ElbowJoe]

Hello. I have been busy preparing my home "fleet" for the winter onslaught. I thought I was pretty much ready with my Freestyle, having just got new tires, changed the oil, fuel filter, air filter, spark plugs, cleaned the throttle body and done a Seafoam treatment. I am about to tackle a coolant flush and fill today. I reviewed the owners manual and found the PTU and coupler lube requirements and learned a little about the Haldex unit. I came to this forum to learn a bit more and need some help. The Freestyle has 118,000 mi on the clock and I don't think these fluids have ever been changed. (2nd owner)

I am wondering if I should take it in to my local Ford Dealer for the swapping of these fluids or attempt it myself. I am a fairly capable backyard mechanic and have replaced the brakes, sway bar links, spark plugs on this. I have done brakes, front and rear axle swaps, control arms, sway bar links and wheel bearings on our Escape. I need a nudge on these fluid swaps and was looking for a video or tutorial on the PTU, Haldex etc but cannot locate anything. I understand Jack Watts has posted some pretty detailed instructions but cannot locate them.

Any help or suggestions would be greatly appreciated. Thanks!!

[Jack Watts]

This is way less complicated than changing the plugs, so if you can mange that, then this will be a no-brainer. The tutorial is at the beginning, but the pictures have gone away. I'm actually due to swap these fluids again, so I'll try to take some better pics. There may be some buried somewhere on here, though.

The dealer won't be of help. They'll only change the fluid when the unit explodes. That's straight out of the factory service manual (the FSM actually has the fill bolts in the wrong location on the picture!).

It's not rocket surgery. Basically, you just need to vacuum the fluids out with a vacuum pump, then pump in the new fluids. So, if you have a mityvac pump or similar, that will help. One suggestion: use vinyl tubing, the smallest OD you can get (use a reducer on the Mityvac or similar). You can get the tubing at any hardware store. Rubber tubing can potentially get caught on the gears and break (happened to one Volvo guy).

In my experience, the rear differential is easy to drain almost all of the fluid, the Haldex unit takes a little more fishing of the tubing, and the front PTU is the most tricky. Eventually though, you'll get out the fluid. The front PTU fill hole is easiest to access going in from the front of the car. The rear Haldex and differential bolts are harder to see, up above the rear sway bar. The fill bolts are right next to each other (13mm I think?), the rear is the differential, the one towards the front of the car is the Haldex fluid.

You should also do the Haldex filter at this point. It's above the oil pump (one of two things held in my two 4mm bolts. The Haldex filter is the top one. The oil pump can't come out without removing the driveshaft flange, so there's no worry of removing that accidentally.

Hopefully that should get you started, but let me know if you have any additional ? and I'll try to answer as time allows. Good luck!

[swespace]

When changing the Haldex Oil, make sure that you run the car for a little bit first. If the car have been standing for a little while the friction modifiers in the oil can separate and create almost a sludge/gel like substance. This goes away after 30sec-1 min engine or even just a few keycycles letting the pump on the awd enable.

Once you replaced the AWD oil and most definitely if you replace the filter you should de-air the system. Again, a few key cycles and then a little driving. Once done open the oil plug again, and insert an allen key or zip tie or similar. The oil should be atleast within 1 cm from the oil fill plug.

Shop around for the oil. Audi, VW, Seat, Volvo, Ford is all Haldex oil.

[Aokakesu]

That's the VW/Audi G 055 175 A2 fluid you're mentioning?
Same as Volvo AOC caulking fluid?

[Jack Watts]

Yeah, the Audi fluid is the same as the Volvo fluid (though they don't sell it in the caulk tubes any longer). The Volvo fluid is the best deal, though: http://amzn.to/2jS134h

[swespace]

Yeah, the tubes was a mess as they started leaking.
You can also check for GM SRX/XTS AWD OIL or Buick LaCrosse AWD oil (2011-2013)

[Aokakesu]

swespace: With the inclusion of the XTS and Lacrosse, it sounds like the same fluid covers Haldex II all the way to Haldex xWD. I'm surprised there isn't a third party offering outside of dealer/OEM.

[ElbowJoe]

Thanks for your response Jack Watts! I am planning to attack these fluids soon. I have a couple of updates.

1) The website for the filter that was provided thru ebay charged me $29 (shipping included) for the filter. I just stopped by the Volvo dealer today to get the fluid $23.05 +tx and found they only wanted $24.95 for the filter. - Live and learn.

2) I checked the website for vivaperformance.com and the fluid is less expensive $18.46 - however it is currently sold out and I don't know about shipping charges. - Oh well. I already got it from the dealer.

I found some diagrams (attached) through the website http://www.fordparts.com/ of the PTU or PTO or Transfer Case (your choice) and the Rear Diff. The PTU diagrams list the drain plug 7A010 and 4C130 - though one appears to be a washer which makes me think it may be labeled wrong. In any case I believe this is the location where the fluid is both vacuumed from and added. Please correct me if I am wrong. Strangely enough, the diagram for the Rear Diff uses the same part numbers and descriptions- so they appear to be using the same bolts. The diff shows two such bolts so I would think one is for the Haldex fluid and the other is for the gear lube.

Finally, I am dreading vacuuming out the fluid from the PTU. Has anyone drilled a 6mm thru hole on the bolt that Jack Watts identified? (I attached a photo.) I would really like to do this to make the drain procedure easier and more complete, but I do not want to do this casually without good info that it works.

Thanks to all - especially Jack Watts and to this website!!

[ElbowJoe]

It appears that the diagrams did not make the attachment on my last posting, so here they are.

[CasualSurveyor]

Re: the bolt being removed for drilling/tapping a drain for the PTU (Ford jargon) or Bevel Gear (Volvo jargon)

Are these photos from the Volvo site showing the same bolt/location? Looks quite different to me.





VS

[Jack Watts]

-the part mentioned in the callout is the drain/fill plug. WOW, don't lose that plug! (a $46.00 bolt? really??).

-the Volvo bevel gear pictures is a GenII, which is why it looks so different. I know that member whoated drilled a drain, but I'm not sure where he did it. I've seen an exploded diagram though, and I'm pretty confident that location will work. Still, drill at your own risk!

[CasualSurveyor]

This is an outstanding thread! Many great contributions.

I would like to ask: what is the correct size(s) of the crush washer(s) for:

1. PTU/Bevel Gear

2. AOC (Haldex)

3. Rear Differential

Are they all the same? If yes, do these fill plugs and washers resemble the ones in this photo?



It would be great to just have the nominal ID and OD for the crush washer(s). There are many generics available for cheap at local auto parts stores and hardware stores. I would like to purchase all needed items before I pull any plugs.