Jaguar Repair: XJS V12 Head Gasket and Shift Cable, head gasket leak, radiator fluid

Question
Hello Howard,

I could use your help on 2 problems that came at the same time. I am short of cash and want to decide if I should repair or run. My car is a 91 XJS V12, well treated, most work done by a Jag mechanic, 110k miles.
1) Head gasket seems to be leaking on passenger side. Ticking as in air leak, then white smoke out of one tailpipe, now out of both; water droplets on floor below tailpipe exhaust. Radiator fluid slightly lower, not clear if related. Mechanic said by phone not to drive, pull both heads, antifreeze may have corroded heads. Engine has not run now in 4 months; no money to have mechanic repair. How can I diagnose or test?
2) At same time, transmission shifter stuck in reverse. Turned off engine, shifted OK into neutral and then park. Now stuck in park (engine off) and shifter moves too freely with no feeling of linking to transmission. Can I inspect shifter linkage to trans without pulling out the center console?
Thanks - Chris

Answer
Hi Chris,
It does sound like a head gasket leak, but you should have either the dye put in the radiator or check the radiator for CO fumes to tell if you have exhaust in the cooling system before you decide to remove a head as it is a large job.
I can't help you on the shift cable replacement because I have no experience nor info on any Jaguar after the 1987 models.
Howard