What Rpm's At 70 Mph For The Sc400

[ricfla]

I ecently had my tranmission overhauled by a highly reccomended rebuilder and I noticed that at 70 MPH it appears to be turning 2500 RPM's. Correct me if I'm wrong but doesn't the engine RPM's normally decrease to about 2200 RPMs as it shifts into final overdrive. Someone in the transmission business told me that the torque converter was not rebuilt correctly. My SC400 has the 3.90 differential in it. I don't know how to calculte RPM's including the std size tires and the transmission final gear ratio of .75 to 1. Is there anyone out there that has calculated this or know what the RPM's of their SC400 turns at 70 MPH?