Dynaflow Parts Interchangeable through the Years?

[Flatee]

I'm new to the forum but have been getting a lot of assistance reading through threads the past few weeks. Reading through all the tech threads with "Dynaflow" in the title doesn't get me the info for which I'm hunting.

 

I recently picked up a 1956 Special hardtop coupe project with a virgin 322 and Dynaflow. The engine has some miles on it and looks like it was parked after blowing a head gasket. The cylinders mic to where they'll need a .030" overbore, to give you an idea of the miles on the engine and transmission. I'm planning ahead for when I rebuild the transmission. In my experience rebuilding TH350s, TH400s, and Torqueflites, it often requires two or three cores to make one solid rebuild. I won't be ready to start the transmission rebuild for some time, so I'd like to start collecting any core transmissions I find locally but don't want to collect ones that won't net me any parts for the '56.

 

Does anyone know what year Dynaflows would have the most internal parts interchange with a 1956? To clarify, I'm not asking what year transmissions can be swamped into a 1956 car in place of a 1956 transmission but strictly about internal parts. The repair manual reprint I have covers 1955 - 1958 Dynaflows suggesting the three years are very similar. Should I stick to collecting 1955 - 1958 transmissions, or will many parts from pre-1955 and post-1958 still interchange with a 1956? I'm talking about parts front anything like pumps, clutch drums, planets, internal shifter linkage/shafts, to valve body springs, etc. Thanks for the help.

[avgwarhawk]

Dynaflow is a very different animal compared  to TH300/TH400 and Torqueflights.  In fact, astronomically different. Needing a donor transmission is not really necessary IMO.  Look up Mudbone video on his Dynaflow rebuild.  The video provides great insight to the engineering marvel for the time. 

Edited July 8, 2020 by avgwarhawk (see edit history)

[buick5563]

Mudbone Dyna series:

 

[avgwarhawk]

Mudbone is ready for his own program on the Motor Trend channel. 

[old-tank]

Mostly all ofMudbone's videos

1 hour ago, avgwarhawk said:

Look up Mudbone video on his Dynaflow rebuild.

Probably stick with 56 if assembling parts.  The service manual is detailed enough unless someone else has been in there and "messed with it" before you.  The only "hard parts" I have replaced that were not in the kits were front and rear pumps and one input shaft along with a few universal joints.  These were easy to find used or from David Edwards or Fatsco.

Take it apart carefully:  I have found missing bushings, wrong gaskets, substituted parts (on my 55 we found that a 56 clutch drum was used that needed 6 clutch pairs and did not work with the 5 clutch pairs for a 55s)

If possible do the pressure checks before removing.

[60FlatTop]

23 hours ago, old-tank said:

unless someone else has been in there and "messed with it" before you.

Before I had a driver's license I hung around with guys who worked in a metal quonset  building on the edge of the muckland. For lunch we would drive across the muck to a little bar where they served cheeseburgers and even a 14 or 15 year old could get one with a beer and sit at the bar. I still remember hearing a story during lunch about a revered transmission "mechanic" who could "disassemble an automatic transmission, throw all the parts in a pile, come back a month later, and assemble it from memory". Almost 60 years ago and just a kid, my take away was don't let some guy throw your parts against the wall and walk off. Now, that is a long lasting memory, but it has been revisited and reinforced so many times... it seems like yesterday. Maybe today if I get my convertible with the 4T60 out, farmed the job out thinking a modern shop could be quicker and better than I. Hack job with a whining bushing. He told my engine vacuum was too high, detune it.

[Flatee]

On 7/9/2020 at 8:27 AM, old-tank said:

Mostly all ofMudbone's videos

Probably stick with 56 if assembling parts.  The service manual is detailed enough unless someone else has been in there and "messed with it" before you.  The only "hard parts" I have replaced that were not in the kits were front and rear pumps and one input shaft along with a few universal joints.  These were easy to find used or from David Edwards or Fatsco.

Take it apart carefully:  I have found missing bushings, wrong gaskets, substituted parts (on my 55 we found that a 56 clutch drum was used that needed 6 clutch pairs and did not work with the 5 clutch pairs for a 55s)

If possible do the pressure checks before removing.

Thanks for the input and for the parts suppliers.