Got an odd situation which perhaps someone can clarify...

Late March, went driving for a bit, not far because the gearbox had been behaving over the past months -- "lazy" shifting especially from 3-4 and 4-5, sometimes slipping for a fraction of a second, and pretty hard knocks under high load. (Brought it to a mechanic to verify the trans fluid level (I had done the oil change myself, wasn't sure all was fine) ; all good).

Then during that short trip, I started hearing a purring sound from the right rear wheel -- clearly the bearing starting to go out. Which I had changed last summer.
On the way back, the sound changed to, huh, metal being grinded into small pieces, I'd say. And the result -- not for the faint of heart.
Obviously, I hadn't made such a good job last summer. I'm guessing that I hadn't properly tightened the axle nut, causing some play.

Anyway, I changed that bearing again, being more careful this time, and -- now the odd part -- the gearbox seems to work normally. Shifts are still a tad slow when it's cold, but I didn't experience any kicks or slips.

I'm not quite sure of how the bad bearing could have caused transmission issues. Even if it had been affecting the wheel rotation for a while (without any sound...), the differential would have absorbed it, right ?

Perhaps the gearbox is simply in a "eye of the hurricane" situation and the next step is that it will explode without any warnings

 

Ouch, total race failure...did you find what you did wrong?

I would conclude the trans issue as coincidence that it is seemingly working better. This guy is pretty good about describing issues and what part causes it and where and how to fix it.
https://www.youtube.com/c/GaryFerrar...ssion%20issues

 

The transmission computer (TCM) also uses the signals from the rear wheel speed sensors for its computations. Your bad right rear wheel bearing probably caused the signal from the wheel sensor to be erratic (wheel vibration/wobble) confusing the TCM.

 

Yes, given the previous issue with the right rear wheel sensor that was covered with grease, I was thinking there may have been some relation again... Wait and see, anyway.

@Highhorse , thanks for the link. Interesting set of videos here... Bit of a frustration though, because while I'm pretty sure I'd be able to tear down and repair that gearbox, I have no means of pulling it out of the car, and no mechanic in the area wants anything to do with it
Not sure what I did wrong : the outer seal was completely crushed and merged into the outer bearing. Looked like tightened too hard, but I'm quite sure it was the opposite : my wrench maxes out at 210 Nm, and it requires 310. I don't recall having done anything else to reach the right torque. There was probably some play, causing friction, heating, and eventually this.
This time, I took a metal rod as an extension. I weigh about 80 kg *, so I put a mark at 37.5 cm on the rod (800 N x 0.375 m = 310, sort of), and stepped on it (not jumping, just stepping). Obviously it's not very precise, but it should be a decent approximation...

* Metric system values, I'm too lazy to convert into your Imperial mess

 

MS states an interesting perspective....if it is how he says, then drive it a bit and see. As for the NM, do you not have auto stores that loan out tools? We have a couple here where you pay for the tool, bring it back and they give you your money back.

Don't let the inter-web intimidate your ability to do those conversions....lol...and don't blame us for this imperial mess, blame the imperial monarchy from England. Though I can say we failed to follow everyone else into the metric era and we now deal with this confugal.

BTW...I looked up Haute Savoie and that's a beautiful looking area.

 

bad LR speed sensor = incorrect gear ratio = trans fail safe

 

Yes, it is beautiful indeed -- pretty nice combination of a lake and mountains. The downside is that there aren't many flat areas, and the XJ is not quite at its best on winding uphill roads (the gas mileage, for one...). These are funnier (and a lot scarier) on a motorbike

Mostly I'd need to lift the car, and there are no "self-service" garages over here.. the closest is over a hundred miles away. Having thought this through, my conclusion is that I should move to a new house with a garage large enough to install a hydraulic lift

 

Right. Well, here's hoping I didn't drive long enough in that state to actually cause an issue in the gearbox... So far so good in any case.