A500 (42RH) (A999 Family) and A518 (46RH) (A727 Family) are both rear wheel drive transmissions with the overdrive section incorporated in the extension housing, and first made their appearance in 1988. The A500, beginning at start of production, was designed with a new electronic controlled 3-4 shift and electronic controlled converter clutch. The A518 however only recieved the electronic controlled 3-4 shift and in 1992 recieved the electronic controlled converter clutch. The A500 and A518 transmissions are found in the Dakota, Pick-up Trucks, Ramchargers, Vans and Ram-50 vehicles. In the Ram-50’s, the transmission is reffered to as the R4AC1 for 2WD versions and the V4AC1 for 4WD applications.
