Transmission change

[msilva12]

I have a 1958 Chevy Apache. I have a 4 speed transmission in it right now. I am considering switching to an automatic transmission. Will this be a direct swap or will the drive lines need to be changed out?

[agnes the dog]

I changed from a 3 speed to a 5 speed last spring. I had to shorten the driveshaft because the new trans was longer than the original. Everything else was pretty straight forward. The driveshaft shortening and balance was about $90 and only took a couple hours. I haven't done a manual to automatic, but you might need to consider cooling lines and flywheel changes too. Maybe someone else can advise?

[OrrieG]

Biggest change is that auto bellhousing do not have the rear mounts for the crossmember. The auto will fit but you have to fab a two piece converter cover. For in town and highway street use most guys take it out. I did not, I will use the truck off road and that crossmember it the tie between the front rear sping supports. You will need to figure out cooling (new radiator or independent), rear tranny support, change the flywheel to torque converter assy, shift linkage and possibly drive line. There are plenty of build threads that show various ways to do it. Here is photo of my TH350 in relationship to the crossmember and my trans cooler. The notch in the crossmember is for my front drive line, at full right sping compression it was hitting.