Leaking rear differential

[dirky123]

Hi everyone!

I just bought a new to me 2005 AWD Freestyle SE a few weeks ago. It has been performing great, but after having some surging issues around 80-100km/h, I took it to a mechanic I know to have the throttle body cleaned (sidenote: not sure if it's made a difference yet)

While he had the Freestyle, a leak started (or was made worse) in the rear differential. The leak in the unit must be new as I'd never found any signs of leaking, myself, and he discovered a large pool on his garage floor the evening after I dropped it off. Upon further inspection the rear wheels had 0 motion when the accelerator was pressed, and the T/C light has been on since I bought it- presumably I've been in FWD without knowing it the whole time. In light of all this his recommendation was to remove the rear drivetrain, to prevent any major damage if/when the differential leaks dry and seizes up.

I did it, and she drives fine. So the question now is- Without the rear drivetrain in place, is repairing/replacing the rear diff necessary? I'm happy to stay in the forced FWD state if it will save me the headache of dealing with the cost, which I'm sure will be high. But he wasn't sure if the configuration would still cause the wheels to eventually seize up once the fluid is totally gone.

[Splicer]

Yes, you need fluid in the differential or you will have even greater expense to be concerned with. Where is it leaking from?

[dirky123]

The circled bit in this picture is where the leak seems to be coming from

E55D96E0-D797-46DB-B7C3-A6F3C0B352F3.jpeg (135.25 KiB) Viewed 440 times

Apparently Ford no longer makes a replacement part. I think I'm going to contact a dealership and just have them remove the differential.

[mmsstar]

You might explore whether the part is available from Volvo.

[Mike51Merc]

The Freestyle differential has two fluids for two different chambers. One is the same old fashioned gear lube for the ring and pinion gears, the other is Haldex fluid for the AWD system. Haldex is in the front section.

The Haldex system has known problems (call it maintenance or repair as you wish), and there are parts that have seals that can fail and leak. The temp/pressure sensor, the filter, and the pump are the three main sources of failure or leaks. None of these is a huge problem, but generally will cost hundred$ to fix (what doesn't today?). If the fluid leaks out, you won't seize anything, but your AWD won't work and you'll probably get the traction control light lit on the dash.

I suggest you look closer at your leak, because the part you point to may not be the source of the leak.

The bottom line is that you can drive in 2wd without the Haldex system, but you cannot drive without gear oil in your ring and pinion gears.

[dirky123]

Thanks for the feedback! It's been decided that the rear cv axles are coming off. After making some repair cost inquiries, it's definitely the path of least resistance. Throttle body cleaning didn't help the surging issue so I guess that's next on the list.

[Mike51Merc]

You can remove the shafts, but I'd say it's unnecessary, unless you're doing it just for better fuel economy.