RayB_911

Decided to clean up the under pans of my C4 after having my back pan off for most of summer. When I pulled the front off I noticed the torque tube was missing a plug of some sort. When I pulled the middle (metal) cover the plug was sitting on it half full of oil. I searched for torque tube. Checked my manuals and don't see a lot of information about the tube.

Should there be any oil in the torque tube?
If not, why would there be oil sitting in the cap?

The front differential looks clean with exception of what appears to be creosol.

Torque Tube


Pulled the front belly plastic off to find this. Plug was missing.




Then pulled the center pan down.




This was oily mess as well.

-nick

Yikes! Torque tube should be completely dry. The input seal on your front diff has to be practically missing for that much oil to get out. Good news- with all of that oil you don't have to worry about any corroded bolts. Bad news, it's kind of a pain the ... to remove the diff. The subframe and steering rack have to come out.

RayB_911

It was/is a little scary. It looks dry so my suspect is that; either the fluid is coming from the differentials inside tube or the oil got in that cap somewhere else. Right now I have cleaned up the mess and looking for where the fluid might be coming. The plastic plug surely was not to hold back fluid.

Thanks.

alexjc4

very common issue. my indy advised to just check the diff oil level at the fill plug from time to time rather than fixing it since the labour is expensive and it comes back fairly quickly. the issue is the input shaft seal on the diff. royal pita to fix, i DIYed mine and its no fun. 5-6 years and 20,000 miles later and its looking a little damp again, so its lasted slightly better than i expected.

jevvy964

Good advice, I hate leaving leaks un fixed though!

I've just finished doing the input shaft seal on a C4, not a fun job! I kinda wish I'd not started it as the top 2 bolts that hold the front diff to the torque tube are virtually impossible to get to. Chatted with Alex about it and he said he got to them through the gear shifter hole which is what I ended up doing but still needed to drop the gearbox mount a bit using longer bolts which lowered the torque tube and front diff enough to get to the bolts.

The factory manual makes it seem fairly easy:
front diff removal

Make sure you replace the small round disc seal as detailed on page 2 of the pdf linked above.

I didnt fully remove the front suspension/subframe/steering rack, I just unbolted them from the car and let it hang on the shocks which gave enough room, I took some pics so let me know if you are going to attack it and I'll get them uploaded.

HiWind

^^ Jevvy thanks for that link! PHEW looks like a major effort but with torn CV boots and leaky diff and stabiliser bar which needs to be changed, as well as some front suspension bushes and one top mount, I guess there's no better time ... hmm