The Stovebolt Site Forums The Shop Area Driveline 3 speed Saginaw

I have transmission with these numbers on side cover trying to get parts for it gm14 3962646 has done rear bearing and would like a repair manual for it

Have found out what the transmission is 28.5/1.68 ratio 3 peed Saginaw would I be better rebuilding this one or buy a rebuilt Muncie 4 speed have sourced parts from garage motorsports in USA they suggest I put a rebuilt Muncie not sure if I use the same drive shaft

Unless the transmission has been changed, the factory transmission would be an SM318 Muncie 3 speed. It is easily identified as having a 4 bolt side cover. A later Saganaw full syncro 3 speed would have a 7 bolt side cover and would have been sourced from a 67 up vehicle. You should be able to find a factory repair manual online on this site or purchase one from several aftermarket suppliers.
Replacement of the the 3 speed transmission with a 4 speed would require a completely different driveshaft and a replacement floorboard as the 4 speed is taller. I don't see any advantage to going in this direction unless nothing else is available. If all the current transmission needs is bearings, they are available from a number of sources. The front bearing number is 6207 and the rear is 6306.
Fred

Thanks Fred yes it has 7 bolt side cover the tranny shop has found a parts list online will leave 3speed Saginaw in it previously it must of been changed no parts available in Australia I could get the bearings locally garage motorsports are getting me a price for all that I need

When you said 4 speed I presumed that you were sourcing a truck 4 speed (SM420) with a granny gear which would require the DS and floorboard changes I referenced. The Muncie 4 speed they are suggesting is likely from a 60's passenger car. They are perfectly fine but would need a floor shift assembly and possibly a fine spline front yoke as well. You may also have an issue with seat clearance with the shift lever. Those Saganaw 3 speed transmissions are relatively cheap here - less than $200 for a good working unit. But of course you are not here.
Fred