The Stovebolt Site Forums The Parking Lot Big Bolts 1947 GMC 1st Series PTO/Transmission

So I have a 1947 GMC 1st series 1.5 ton truck and decided to put my anthony dump bed/ hoist on it and found out there's no pto shaft! I have a later transmission, a SM420 with a pto shaft and was wondering if I could use the pto assembly. According to "chevy old car manual project" specifications on both are a 6 bolt SAE standard with 33 drive gear teeth.... BUT the SM420 lists the drive gear type as helical while it says nothing about the crashbox are they the same? I also have the bell-housing that came with the newer SM420, how hard would it be to switch everything, will the petals and clutch line up and will I have to shorten my driveshaft? I don't have a torque tube shaft it's a two piece like the newer trucks. Any help would be appreciated?

The first series has spur type gears. The SM420 has helical gears. The pto is different in the two. The bolt pattern on the clutch housing is different also. However, the clutch housing to the engine is the same. Swapping everything leads to clutch linkage and rear engine problems, but it can be done. I would first look for a pto on an old farm truck. About all that ever goes bad on old pto's is the seals. If you can live with the old sliding gear transmission, it certainly be much easier putting a pto on it. Another possibility is converting to 12 volt and using an electric hydraulic pump like lift gates use.

I have one to fit your 47 first series if interested.
Give me a call, I am close to Topeka.
785-845-4507 Doug

HI,
I,ve done the trans swap you're looking at recently. The bell housing will have to be modified if you want to use your existing pedals. Jim Carter offers it, but
you have to send them your bell housing. Good luck, steve.

Perhaps it just needs new mounting hole(s) drilled and tapped plus perhaps retainer turned down or hole in bellhousing bored out? Local machins shop might be able to do it. I have a 1st. '47, w/ pto, however, I wish to keep them together.