My son has a '89 Ranger, 2.9L, w/ A4LD. The A4LD has just died- Non-drivably Slips in any gear above 1st, and will hardly move in 1st. My son thinks that the best solution is to put a 5-spd manual in it. From reading other forum threads it appears to me that the M5OD R1 is the preferred...