I'm trying to source an overdrive Moss gearbox for my 1959 Mk1 that I'm restoring as the car's original gearbox has been separated from the car at some point. My question is, is there a difference in ratios on Moss gearboxes for 2.4 and 3.4 MOD cars?

Thanks.

 

AFAIK the difference would have been in the rear axle ratio.

 

That is my recollection as well...the gearbox ratios are the same but the rear axle ratio differs. However, the overdrives differ in hydraulic pressure between the 3.4 and 3.8 liter...I think maybe the 2.4 as well. I purchased an old non-synchro Moss box for an auto to manual conversion on a 3.8 Mk2. The gearbox I got came from a 3.4 liter, so I had to shim the overdrive relief spring to achieve the desired pressure. I know the 3.8 overdrive also has 4 additional return springs, but I deemed this unnecessary. We'll see if I was correct when I finally get it on the road. The hydraulic pressure engages the OD...the springs act as the release (when the hydraulic pressure is released). My assumption is that the OD will release a little more slowly, but have the right clamping power for the 3.8.

Tom

 

Thanks for the replies. The ratios being the same makes my search a lot easier. Very interesting about the overdrive hydraulics, I had no idea they were different pressures.