So I have been researching in the Cummins forum for info on the transmission. It’s basically a 727 with overdrive. The tps or throttle position sensor is used to tell the transmission when to shift into overdrive. As it turns out my transmission works fine as long as the overdrive is shut off. I found that several owners had taken out the factory tps and put in a pot that mounted to the dash. This seemed to fix many of their overdrive issues. So this morning I took off the tps and found that it is not being turned as the throttle is moved. The female hex on the throttle shaft was a bit damaged. The adapter that connects the tps to the throttle shaft is adjustable. I made sure the tps would rotate as soon as the throttle was touched. That cured the overdrive issue!!! Now it shifts into overdrive right around 35mph just as it’s suppose too!!!