305 v6 transmission

[eyonab]

I m trying to find a transmission for my 64 gmc with a 305 v6 my old one is done my side cover has 3846157 gm AND at the top of those numbers is the number 23 I can find all the chevy transmissions I want but cannot find this one because the input shaft is different. what do I need to do to convert it from the gmc transmission to the chevy PLEASE HELP!!!!!!

[David R Leifheit]

Originally Posted by eyonab

I m trying to find a transmission for my 64 gmc with a 305 v6 my old one is done my side cover has 3846157 gm AND at the top of those numbers is the number 23 I can find all the chevy transmissions I want but cannot find this one because the input shaft is different. what do I need to do to convert it from the gmc transmission to the chevy PLEASE HELP!!!!!!

I must be missing something. How is the input shaft different? I have swapped transmissions back and forth in my trucks, never worried about "Chevy" vs "GMC" transmissions since... well, I couldn't have told a difference. Even swapped the non-synchro 3 speed for a toploader 4 without making any changes other than longer driveline.
Automatics might be a problem (haven't played with those yet) but manual transmissions have not been any problem.

Of course I have not played with newer transmissions so their might be a difference there. Although I have to admit I never asked the year of any transmission I got either. Is it GM, then good.

Now I did have one transmission which gave me trouble, it kept breaking off the nose piece that goes over the input shaft (that the throwout bearing rides on). Replaced that a couple times before it quit doing that. As I recall the gentleman at the wrecking yard told me it was somewhat common, especially since he had several of the top loader transmissions but only one or two had that piece intact. Which I ended up buying from him.

[TJ's GMC]

Does yours have a 3 or 4 speed tranny? If it's the 4 speed it should be an SM420 and any ol SM420 should bolt right up.