200r4 swap to 400turbo

[buickpete]

A few years back a guy talked me into installing a turbo 400 trans. in my 86' GN because it would have been my 4th or 5th rebuild for the 200r. But now the 400 goes through the gears as soon as i take off, about 30' and i'm already in drive. And the stock 200 shifter cable doesn't have enough throw to manually pull it all the way down to first, if i put it in 2nd it will hold the shift all good. Is there a differant cable out there for me or does anyone know where i should start. Sorry for the long post, i need help

 

[SSedan64]

Sounds like the TH400 may have Governor problems.
A shifter cable from a car that came with a TH200C or TH350/350C should work with the TH400.