It is probably no big deal but i would think thrice before cutting a hole in the body!

I think blowing from the fill port every time you change the fluid would be sufficient, it doesn’t look too hard to uncap it with s long reach tool.

 

@Ray Ray The “crud” that I extracted from the various corners of the XJL eDiff (and from many V6S LSD’S) seems to be impervious to air flow.
I am thinking the oil sludge with friction material is an accumulating, semi-solid formation.
This would favor the use of direct air pressure or a auger tool (the zip tie cleaning method) to clear the vent tube.
So I am supportive of @diablo2112 approach.

respectfully,
Herman

 

good to know that!

do you know if there is enough clearance for the crud to come out with a fluid change?

 

Ray,
the crud (friction material and metal paste suspended in oil) seems to accumulate at low points and places with burs and threads (like the axle seals, and the fill port).
See my video above at 5:35, 6:05 and 9:50, where I pulled crud out of various corners of the diff.
I am thinking these small collections of crud will stay hidden in the unit when the oil is refreshed. The only place the crud will do any harm is in the vent tube. So best to clean that out with compressed air or a pick/zip tie.

 

I was hoping when cleaning from the port side, the sludge would be suspended in the fluid and come out with a flush.

By clearance i meant if the inside of the diff had enough space for the sludge to travel through with the fluid flush.

i guess the best thing to do would be clean the port, run the car for a bit and then change the fluid to get most sludge out.

 

Not to get too far into semantics, but I think I'd call it a cover, not a cap. It doesn't need to be removed unless you're doing something like the zip-tie method of cleaning. It covers the hole but the inside of it is designed that it's a couple of millimeters from seating with passage for air.

If I were to use the fill port to clear the vent I'd either make sure to use low pressure air or slight vacuum. The small handheld Mity-Vac seems a good choice. It's small enough that if the vent is clear, you'll never be able to get any appreciable vacuum. If the system holds even a slight vacuum, you'll know the vent is clogged.

 

@Ray Ray
After looking at several diff units, I suspect there is no good way to rid the housing of the gunk.
There is room for the "sludge" / "crud" / "grime" / "gunk" to fall from the breather tube, back into the differential housing.
But it is heavy and schloppy... and I am not sure if it will flow or slide across the bottom of the housing while draining the oil (cold or hot).
I have found gunk in all sorts of corners and crevices, so the only way to rid your diff of the sludge is to remove the diff from the car and disassemble it.

That being said, I think the best path of action is to simply clear the vent tube with a zip tie, and refresh the rear diff oil. (every 25k miles?)
Then consider a rebuild of the diff, if it starts to loose it's LSD action (worn friction discs).

@lizzardo I think a small amount of air vac or pressure may be insufficient to move much crud... rather it would just run through the small hole/opening.
I think the zip tie method is better at cleaning out the passage.

 

I just checked the spare unit in my garage, and no gunk was apparent on the zip-tie I used. I can't remember what the mileage was on the unit but the supplier has other 6MT parts. Based on what I recall of the VIN they're from the same car, so 63K miles. You'll get to see the insides of it soon enough.

I was thinking low pressure to eliminate possibility of damaging a seal, and keeping the operation manageable entirely from underneath the car. You're the Jaguar diff specialist around here, so I'll certainly defer to your judgement.

 

@lizzardo The V6 rear diffs (with friction LSD) also accumulate crud (if driven aggressively?),
but the V8's (with eDiff) seem to develop more issues with vent pipe clogging which leads to front pinion seal leaking.
I will report back on how much gunk I find in the unit you send back to me.
But it would be nice if a simple sequence of applying compressed air to the fill hole could liberate any crud in the vent pipe.
Perhaps some experiments are called for!
How much air pressure causes pinion seal failure?
How much air pressure will clear a clogged vent pipe?
How much crud can a wood chuck chuck?

 

Another concern I'd have about pressure at the fill hole would be blowing off the little yellow vent cover. If that comes off then it would be much easier for water and other BS (Bad Stuff) to get into the diff. I'm not sure how easy it would be to put back on, even assuming that it blew off into place you could find it.

Maybe I need to crawl under the car and see about access so that I'm not confusing things with impossible suggestions.

 

Update: May 17, 2024
The folks over at RacingDiffs have an upgraded set of eDiff clutches in their production shop.
I will receive the first set of clutches from them and do a trial fit up.
These upgraded clutch discs should provide robust operation for the Jag eDiff.

Drive Well,
Herman