ATF fluid recomendation for 56 Auto Transmission

bullrunmotor

Senior Member
Shop has completed rebuilding automatic transmission for my 56. Technician said synthetic ATF would be fine. Anybody got an oipnion on synthietic vs Mercon? Thanks in advance.
 
I have always use Dexron/Mercon fluid. I think everyone will agree it is the recommended replacement for type A fluid.
Sometime you can still find type A in farm supply stores, but it is not the same formula as the original type A anyway. (No whale oil). synthetic is used for lubrication properties, so might as well get Dex/Merc.
 
Shop has completed rebuilding automatic transmission for my 56. Technician said synthetic ATF would be fine. Anybody got an oipnion on synthietic vs Mercon? Thanks in advance.

MERCON V is synthetic and is FORD's replacement for previous MERCON fluids.
 
If the seals are compatible with synthetic then it will function but I don't know how well. Synthetic oils like to find their way through oil seals of certain materials with their low viscosity ratings. It works OK with Viton and fluorosilicon type seals but not as well with the old neoprene. I think I'd go with Mercon or Dexron II if your going that route. The old Ford-O & Merc-O-Matics have never really been updated to modern specs. They still use the steel and bronze clutch plates in the clutch packs. Slippage will ruin them. If you need a more positive shift, the older type F should be used.
 
I would trust the TECH at the shop. That shop will not put something in that will cause a repair situation within the warranty.

Lubricants have changed greatly since the fifties as well as friction materials/gasket and seal materials. I doubt very seriously they located a NOS repair kit and used it. The kit would be of the latest design.
 
Many modern techs are taught very little about the early type transmissions. I only trust a guy that has a lot of experience with the older units. They literally don't build them like that any more and haven't for many years. The old Ford AOD was the last transmission that was even close.

I've had more than one tech ask me how a non electric transmission works. If they see a bronze friction plate they look puzzled. A lot of the new friction plates are composite lined but thickness varies. Folks start wondering how many plates to put in there when the stack up doesn't match where it's supposed to go. It can end up as messed up as a soup sandwich. I just hope most folks that own these transmissions don't end up with techs that have no experience with them.
 
Use what the rebuilder suggests. I had two automatics (C-4's) done at a shop that recommended synthetic. No problems with it.


If you use something else and the trans go sour, the shop may not stand behind it because you didn't follow their recommendation.
 
Bullrunmotor, I would suggest going right to the owner of the shop rather than going through the tech since the owner is the one who will have to stand behind it. Good luck with your ******!
 
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