69'442

Took my 70 442 with dualgate for a drive to the beach. As I started on the way home I noticed the car would not shift into third gear. I slowed down to a crawl and then tried going again. This time it would not shift into second. I stopped and put it in park and then tried again. No second gear. The shifter was always on the left (her side). I slowly drove it home and started playing with the his side. I found the car would shift fine if I left it in third. It ran like it was in drive on the her side automatically shifting thru the gears. I got the car home. A few weeks ago I had a problem of it not shifting till it was warmed up. The filter was changed and fluid level good. I changed the modulator and it ran fine for the last 5 times I drove it. I don't think the dualgate was ever set up properly because whenever I tried it it would shift on its own. Could this be the cable adjustment, governor or the transmission? Maybe the dualgate needs to be rebuilt? Thanks for any advice.
Bob