I have a turbo 400 tranny that had a 32 spline 203 on it.. still has adapter for that combo.. Is there a adapter for the toyota tcases 
Yes, a company by the name of
Doubler OffRoad Designs in Carbondale, CO has what you need.
They make a 8" long adapter that offers a 2.0:1 low range. Give them a call at (970) 945-7777.
I spoke to Marlin and he said that he has no future plans with the 203.
Marlin said that your 203 sitting behind your Turbo 400 (700R4 without overdrive) uses a 6 bolt rear flange and that we would have to provide flange adapters to go to the 4 bolt toyota pattern, and then that would require more driveline mods, and ohh boy...
Regards,
BigMike
