Jan,
The pivot with 3rd gear selection rearward is forward i.e. the rod is forward so either moving it further forward or extending it should correct it if it is not fully engaging.
You can usually get a good feel from where the shifter sits in the gate, if in 2nd the shifter touches the forward gate and in 3rd it isn't close to the rearward then an adjustment is probably warranted.
Julian
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.