No Reverse!

Hi
Could I please ask the forum for your advice, I have PM’ed two of our forum members and used there valued advice, but I am still in trouble!

I have just imported a Pantera # 6791 from the US to Australia.
The importer unloaded it and said the clutch “smelled hot”?

On getting it home and reversed off the trailer, selected 1st and drove up the slope into my garage, no problem, checking around the car I noticed the clutch slave cylinder rod was over extended and had no free play, I set up the clutch slave cylinder as suggested on the forum (and PanteraPlace) and the clutch takes up and seems to be OK.

The gear lever was forward and a little to the right in the selector gate, so I loosened one of the universal knuckle joint bolts and slid the lever on the splines to the centre of the gate, re tightened and tried forward and reverse several times with the engine running, all seemed OK.

I reversed out of my garage and took the car for a run, all worked well until I tried to select reverse, the lever seems to go over OK to reverse in the gate, but does not select reverse, no grinding, nothing.

I have checked and greased the trunion bearing under the left exhaust header.
I have removed the reverse light switch, (and selector housing cover).
I have checked the two studs behind the rubber plugs, they are tight.
I have removed the gear lever detent,
I took the chrome gate off at the base of the selector, and still could not select reverse,
I am getting all 5 forward gears, checked by driving the car.

I slackened the “turnbuckle” and made certain the gear lever was central in the gate, it sits in the 2 and 3 slot (left and right) and central fore and aft, as per workshop manual.
I changed the Clutch Slave for a long throw SS one (Old one was leaking a little).

I took some measurements from the ZF selector housing to the shoulder of the first knuckle joint, to make sure the shift was moving in and out correctly, and not sliding in the splines on the Knuckle joints, I also applied marker paint to the splines so as to witness any spline movement. All seem tight.

Any ideas what next?, I uncoupled the first knuckle joint from the ZF , and could not select reverse directly at the ZF box?.

I have all the workshop manuals, the red hand book, the ZF service manual, the ZF box has been rebuilt by Dennis Quella, I have the invoice, showing what was done.

Am I missing something?
Thanks in advance.
Rgds
Terry.