manual trans always gets my vote. Just better experiences with them. Not to say I haven't had some issues with manuals either but never left me stranded.
Don't think I've ever had a problem with an SM465.
I have...had one that would pop out of third (some call it "second"--the gear before 4th!)--at first I could hold it in gear,but eventually it would force itself out under acceleration or a hill climb.... a snap ring broke and got munched in the gears..decided to replace it instead of fiddling around trying to fix it--(just like I do with a ailing automatic,since few ever seem to work right again once they act up in my experience)..
The one I replaced it with,both were the earlier 10 spline output type,had chowed the output shaft splines some, and the coupling between the transmission and transfer case too--a new coupling silenced the annoying rattling noises for about a month,then it started in again--I decided to turn the radio up and added a graphic equalizer amplifier instead of getting transmission #3...it never failed,but I never felt confident about it either..
I've had decent luck with TH350's and Th400's,it took 8 years of hard plowing before the TH350 in my '77 GMC lost reverse...I'm not a woman or child,but I hate plowing with a manual transmission,reverse is slow as hell,and you'll lunch a clutch in a few winters,usually in the middle of a bad one...-and I do have left leg issues and found a mechanical clutch and a three fingered pressure plate 12" in diameter a poor combination...a hydraulic clutch with an 11" diaphram type one is much better..
Also the newer 32 spline SM465's were much smoother shifting and that pretty much eliminated the other issues earlier ones had..
I say no matter what transmission you have,they all have their down sides...I wouldn't mind having an Alison !..they seem pretty tough,garbage trucks use them--those are a lot more than one ton..
