Not quite a year ago had my '85 240 professionally converted from auto to 4 spd/OD. Best decision ever made. One problem I noted at the time here, the manual OD is less than the auto's OD ratio (.79 vs .69). Hence, I lost about 7 mph cruise speed. At a fairly quiet 2600rpm with the auto, it was 75mph. Now with the manual it's about 68. My car has the 3:73 gears, needs the 3:31. Cruising 75 now is rather noisy at 3000rpm. The Bentley doesn't even mention changing rear gear sets, assuming it's a huge task or not possible outside a dealership. Not like US cars where you pull the axles and pull the third member and stick another in. Do I assume the only way to go to the higher ratio is to change the whole axle assembly for a 3:31? That looks rather daunting in disassembly/reassembly though probably doable in my garage just not sure I'm up to it. Hmmm. Any thoughts?