I have a 2007 Volvo XC90 V8 AWD. I noticed driving on a flat highway the 6'th gear the ratio of SUV speed in miles per hour to the piston revolution speed in thousand rotation per minute is 40, especially between 60mph and higher. Now after a repair with modules replaced, the ratio has become lower at around 35 or even lower. Is this a problem? Is this controlled by the module? Should I bring the car back to the repair shop/dealer?
Yes, I'd take it back to the shop to see if there is something they missed. While 300 rpm at 60mph is not a huge difference, to me this is about the difference of when a lock up torque converter isn't locking up. This could be a programming issue which wasn't taken into account with the new CEM. While it isn't a huge issue, it will cause greater wear of parts and cost you in fuel mileage.