My Jaguar was on blocks for 28 years and i refurbished the complete car to its original status the engine and transmission is original and nothing has been changed but was refurbished.
all is in order and working fine except that with a test run i discovered gearshifting problems in third gear, once it selects third gear in motion (normal driving conditions on a flat surface road) the transmission chages back to 2nd gear and stays there.
i have done all kinds of test on the gearbox and torqeu converter and could not find any visible problems even presure tests was done with air on ports everything seemed to open and close on the gearbox as it should be and the correct oil is in use.
can anybody assist me in the faultfinding problem please ?

Thank you kindly for the response regarding the switch yes it is active and working fine.
A plugged point nearest to the outgoing drive shaft i discovered losing presure when 3rd gear is engaged is this normal ?

Hello to members of the Jaguar Enthusiasts Forum.

Thank you for the speedy response to my two previous e-mails. From enquiries that I have made, I believe that some modification or replacement had possibly been made to the oil transfer tube currently fitted to the automatic transmission of my Jaguar. My request is whether you could trace a drawing with specified sizes of this component. The parts section of the Jaguar Heritage DVD, JHM 1117 that I possess does not provide sizes on drawings, or fault finding. Local transmission service providers are not able to help me either. (Johannesburg, South Africa.)
The reference numbers of my car, 1964 Jaguar 3.8 MK2:
Engine No. LC9741-8
Transmission DG-250-MJ
Serial No. JBC 18316
Tube in end of Main Shaft for Oil Transfer (J.20-392)

Do the workshop manuals that you list include fault finding and repair methods for the automatic transmission of the model/type described above?

We have again separated the transmission box and torque converter, then removed the transfer tube to be photographed and made a drawing with actual measured sizes. We also checked to ensure that the tube provided a firm fit through the “o”ring at the centre of direct drive clutch. (Photo and drawing attached).

Is there a way that we/your Enthusiasts Forum can determine if this part is of correct size to be expected to operate as necessary?

Should we try enlarging the 1/16” hollow at the narrow end of of the tube to allow more transmission fluid to pass through?

Your input is appreciated. Our testing effort has thus far not provided success.

Regards.

[As per our discussions i am still not closer to solving the problem regarding my cars gearbox problem being that it does engage to 3rd gear but does not stay there i will really appreciate it if any body can assist me in solving the problem ]

Good day Jaguar Forum
Regarding all previous discussions I would like to carry on with discussing the current problem i still have regarding the fact that despite all the effort and recomendations i religioslly followed, the problem regarding 3rd gear engaging but does not stay engaged persists.
I will appreciate if someone can maybe recomend ways on how this can be resolved that may have had the same experience regarding this problem, I am sure that it must be some minor problem being that the fact that uptil now no visible fault was found.