Re: 1940 overdrive?

Posted by HH56 On 2014/3/18 21:15:12

They did change. The R6 in 39, R9 from 40 thru mid 48 and then in 48 a change from the R9 to the R11 in mid 22nd series production. R11 lasted until the end of production. Mechanically essentially the same although the case was different 51-4 and then again 55-6.

R9's are quite different mechanically as well as being electrically more complex. The R11 is a much more refined unit with simple electrics. It was made available via kits when R9 supply ran out and also for those owners experiencing problems with R9 equipped cars who wished to buy the upgrade.

The pre V8 complete transmission & R11 assy will bolt in place of the trans & R9 equipped on most cars but there are some major details that also need to change if the conversion is made. The R9 is a good unit but does have issues if things are not kept in very good order. If you have the option to get the R11 complete, it would probably be more advantageous but would not be correct for the year -- although there are some on the forum running the R11 in prewar cars.

1949 Service Counselor Vol 23 #2 details the differences between the R9 and 11. 1947 Vol 21 #15 details one of the issues and main reason for the change and kit. Vol 23 #4 details the kit a little and has instructions on how to install & what needs to change if the kit is installed.