It never gearbox and speedometer

Hi all,

Finally after a winter of welding,filler,painting,making fuel lones,service I thought it would be good to run the the car on pillar with wheels in air just to see if anything more would occur and sure did.
Speedometer work in idling in drive but as soon as I put foot on gas pedal the needle goes to 0 on speedometer and when rev goes down it catch up again at 20km/h. Wire seems to be ok but my car has geardrive in to box and is a 1982?
I also hear a knocking noise when acc.and deacc…knocking seems to come from rear support of gearbox. Bushing seems ok looking on it
Finally a contact housing hangs down and I striped it back. I also notice that a cover is missing
So here are my questions:
Speedometer:is my problem a typical angle gear problem?

Cover:surely there should a cover over the big hole,right?
Knocking noise when gearbox moves:Bushing broken?
Wire harnes: what is the 4 pole contact for?
Top picture show contact and cover missing. Below is just angle gear

Check the rear transmission mount bushing.

Surely the 82 should have an electronic speedometer, Johnny…??

…which doesn’t explain its behavior - which indeed sounds more like one of a cable driven one. If cable driven; check the square drive connections for wear causing slipping - and inspect the cable for kinks? If electronic; it’s most likely a bad electric connection, or a faulty speedo - I trust the engine is running OK…

xj6 85 Sov Europe (UK/NZ)

Hi ,
Well it is gear driven for sure but a 4 pole contact housing hanging in area so maybe someone has exchanged in the past?
I made a test drive with nearly no brakes and speedometergoes up to 40 km and then stop. I have checked in gear end and squareis fine. I have ordered new gear and itwill arrive on tuesday.
Brake pistons has been greased up and moved back and pushed out again but very hard pedal force is needed. First I thought it was rust on discs but that is gone so next thing to check is vaccum…then steering gear dust boot is bad and…
I have 4 Jaguars and my idea was to make one ready for road without beeing too picky and drive oldtimer insummer and then focus on the other 3 but start to doubt it will be ready for MOT before summer…

It spells lack of booster assist, Johnny - so checking booster vacuum seems sensible…

One test; there should be a brief ‘hiss’ of air entering the booster through the coaxial air inlet at the pedal - when the pedal is pushed. Stopping as the pedal is constant. A continuous ‘hiss’ implies a leaking booster…

xj6 85 Sov Europe (UK/NZ)

I have not had time to look deeper in to it but drowe it in to garage and when starting I felt that vaccum is working on the pedal. It will rain for 1 week now so will make more test drives after that.