OK, Bert, here's the skinny.
All Star and Durant frame mounted trans are basically the same. Even though the main cases have various minor differences, they are all the same for function and fit.
Star C and F share the same shifter top but the Durant has one of it's own as does the M and R series.
The A & B series Durant input shafts had 8 splines whereas Star, all models, had 10 spline shafts and corresponding clutch friction plates.
The shared parts common to all cars is the countershaft gear and shaft, second & third slider gear, first & reverse slider gear, reverse idler gear and shaft. Speedometer parts are the same for all cars.
Also note, there are no oil seals on the input shaft or the rear shaft. Provision was made for a close fitting spiral groove inside the front and rear cover to kinda keep the 600W oil in the case.
The countershaft gear shaft is a fairly tight fit when installed to assembled position but will eventually seep oil past these joints.
I have it from highly clandestine sources that these various leaks were engineered into the car to keep the driver on his toes checking the oil levels.
Judging from the condition of a lot of components that I have come across, this philosophy didn't work too well,,,,,,,
The early A-22 Transmission cases and their mounting is signifently different then the later Durants and Stars...The 1923 A-22 case bolts ridgidly to the back side of the crossmember and has provisions for the emergency brake to pivot on the right side, the top cover with shift tower centers directly over the middle of the transmission...I am reasonably sure that Spicer built all these transmissions although it is difficult to find any manufactures brand on the gears or parts...When I installed the later model gears and shafts in my early Durant case I found a few small differences and found that Spicer also made some up-dates or improvements...The sliding gears are basicly the same, however Spicer added approxamently 20% more length to the splined portion of slideing gears, they also added length to the direct/third gear lock-up collar, there is also a difference where the 1 1/2" splined shaft passes through the rear bearing, the early models are machined smaller with shoulder whereas later vintage is the full 1 1/2" and use a snap ring...The speedo drive and driven gears are smaller on the A-22, so in my changeover the only actual modification that I ran into was that I needed to enlarge the speedeometer drive gear I.D. to accomidate the later splined shaft, Also I recall the input shaft on the A-22 was machined with a threaded stubb for retaining the drive joint and the later shaft being drilled and tapped, however in my case this feature didn't present a problem...So if you are looking for gears and parts I think they are pretty much the same but try and get later up-dated stuff.
Bill
Where Are You From? Yuma, AZ / Leavenworth, WA
Do You own a car built by Durant? '23 A-22 Touring / '29 Model 40 coupe