Auto Gearbox Pilot Bushing - I Don't Understand...

[E55BOF]

Some will have seen that I've just done a transmission fluid change on my 722.6 gearbox. Intending to change the pilot bushing to avoid the 'gearbox loom and ECU full of oil' problem, I undid the 7mm centre bolt, but could not get the old bushing out, so left well alone. (I didn't want to use force, break off a bit of the plastic, and end up cramped under the car with a problem I couldn't fix and the car off the road).

There was no sign of oil leakage on the outside of the gearbox. What I don't understand, though, is how replacing the pilot bushing and its two o-rings would stop oil getting into the loom. I had assumed that the oil came through the innards of the connector and up the loom that way. The two o-rings seal the outside of the pilot bushing into the gearbox, not the inside from the loom.

I did a fair bit of internet research before I started, but I'm still baffled. Unless the oil comes out through the outside of the pilot bushing, then works its way by capillary action into and up the loom, I can't see how this fix works. Am I missing something here? And if not, presumably there would be oil on the exterior of the gearbox around the pilot bushing if the problem starts to occur on my car?

Could someone clear this up for me? Please?

E55BOF

 

[Justin1600]

If the gearbox oil level is correct and not over filled. Take the multiplug off of the pilot bush, if lots of gearbox oil comes out then the conductor plate above the gearbox valve body is faulty, allowing oil out through the electrical connector. As you say this will end up going up the wiring to the control unit.

 

[E55BOF]

Ah-Ha! Now that DOES make sense. There seem to be quite a lot of people out there in the ether that confise the two faults, though. If my pilot bushing starts to leak, I have the spare new one.

There was a small amount of oil around the multiplug when I removed it, but the box had been drained and the sump off for over 24 hours. Does this mean I probably have the problem? Presumably, to fix it the valve body assembly would have to come out and the conductor plate be replaced; does anybody know roughly how many hours' labour is involved, and the cost of the connector plate?

E55BOF

 

[E55BOF]

Found the plate on eBay; around £100, so not too bad. Anyone know how much of a job it is to replace it?