Re: 1947 R9 Overdrive

Posted by BDeB On 2015/8/11 1:09:28

As far as I know the 3 and 4 pinion planetary assemblies should be interchangeable between the R9 and R9-A overdrives. The mating sun gear and ring gear are the same for either unit. As long as the depth of the cage assembly is the same it should work.
The main difference between the two other than the number of planetary pinions is in the freewheel cam unit. The R9_A has longer rollers.

Some of the parts that are different and referred to by the Group number in the parts book illustration:

3.282 Freewheel Cam Assy. and associated components
3.274 Clutch Hub
3.294 Main Shaft (Rear) which has a deeper recess to accommodate the longer rollers