I got a good 73 Th-400 from another Riv and installed it in place of the Th-400 in my 71 Riv that was leaking like the Exxon Valdeze. The plug for the kickdown on the drivers side of the 73 trans has a single vertical brass tab sticking out where as the one on the 71 has a vertical and a horizontal pair of tabs. I plugged the connector onto it but will it work this way or do I need to do some parts swapping ?
That extra tab is involved in your emissions system; probably spark advance. Don't confuse it with the 65-67 switch pitch control tab. The 71 no doubt goes to a switch screwed into the valve body, which tells if the car is in high gear. If you want to retain this feature, you need both tabs and either swap valve bodies, or drill & tap the 73 so a switch will screw in (IF there is enough metal). Check your 71 manual. Rebuild that 71 trans; might just need a $30 soft seal kit to fix it up. Bruce Roe
