550’s are OK, however, to get OD, the third gear position is removed, so shifting skips that ratio which limits on to second gear if one has a load.
Ed
Should have mentioned that point, 540GO has the same ratios 1 - 3 as the 540GD (direct), 1st - 6.05:1 , 2nd - 3.31, 3rd -1.84. in the direct 4 is 1.17 : 1. Having that gear just under direct is what give the pulling power the OD unit lacks.
