We've been working on a 190SL that has a M116 (380) engine installed along with a pagoda disc brake rear axle. The diff ratio at 3.69 was way too high and using the engine number I was able to look up the possible diff ratios the original donor car would have had. This was either 3.27 or 2.72.
Now, we know that the lowest ratio you can fit in a pagoda is from a saloon axle with the cooling tube and a ratio of 3.27 but after looking through my technical data books I realised that the diff ratio in a 6.3 is 2.82 and is LSD to boot.
Now, where to find a used 6.3 axle? I found one in Germany ($$$) and drove over to collect it and pop in to retro classic exhibition at the same time.
The 6.3 has completely different rear caliper mountings to the 113 and my initial thought was to cut off the axle tubes and graft on some tubes from a 113 axle. However, just before I started cutting I thought that maybe I might get away with simply unbolting the diff carrier from the two axle halves and swapping them over. Guess what? It works......
So, if anyone ever feels the need to go lower still on their diff ratio, it can be done.
