[Healeys] Overdrive problem #2

[warthodson at aol.com]

A friend's BN7 overdrive won't engage. The electrical system is operating
correctly. Initially, the alignment lever did not appear to be precisely
aligned with the alignment hole, so we adjusted that per the manual, but that
did not fix it. Next, we went for a drive with the tunnel off & when the
overdrive solenoid was activated we pushed the alignment lever farther down by
hand to see if that would cause it to engage. It did not. The overdrive has 30
Wt. non-detergent oil in it.  What are some of the possible causes for this?
Our club is going to invest in a pressure gage. Where can we purchase one with
the correct fittings, etc.? What tests can we perform with the overdrive in
place to isolate the cause of the problem? I am reasonably sure the overdrive
cannot be removed without also pulling the transmission, but like to confirm
that.
Gary Hodson