As compared to the 95/96 4R, the 1997 5R adds an Output Shaft Speed sensor and an Overdrive Drum Speed sensor; both mount through holes in the trans case. The 5R also uses a completely different Transmission Range Sensor and matching engine/trans harness. There may be more.
The extra "1st OD" gear only functions during heavy throttle acceleration. The transmission controls skip it any other time. So, potentially slightly better acceleration but no impact on fuel economy. Even if it were possible to swap parts to create a 5R, would that be worth it?
Last edited by rwenzing; 10-12-2010 at 04:17 AM.