Quote:
Originally Posted by U47
Confusing to many by it's many names; Hydra-Matic division which built the trans calls it P 315 controlled coupling Hydra-Matic, Cadillac calls it 315 Hydra-Matic, Olds Calls it Jetaway HydraMatic ( and also calls the 1964 and beyond ST300 in the F-85 & Cutlass Jetaway ) , Pontiac calls it first StratoFlight HydraMatic-Later, Super HydraMatic.
HydraMatic division also designed and built Roto HydraMatic. Roto is also a controlled coupling HydraMatic, and is the only automatic trans to have a fluid coupling and a fixed position stator, it is the only automatic that when in second gear(third range) is in complete mechanical connection from the engine to the drive shaft along with the invention of the lock up torque converter by Packard in the UltraMatic in 1949. Roto could have been one of the best automatic's for drag racing had it been for two things. 1. gear spacing between ratio's and 2. heavier duty components. HydraMatic Division calls it a four range three speed due to torque multiplication in first gear of 3.50 to 1- later through first gear at 2.93 to 1, 2nd at 1.56 and third 1 to 1. this is why it's called a three speed with four ranges. The trans has less parts than Super HydraMatic so it's complexity is less in that sense, but is more complex in it's operational duties in which the small fluid coupling like in Super HydraMatic takes the place of the conventional forward clutch, which Roto does also, it also takes on the duties of the large fluid coupling in the engine - transmission connection. Because Roto's small fluid coupling (same size as Supers front coupling) is so small (8")there is a need for a flywheel instead of a flexplate. One other minor drawback to Roto is because the coupling when filled ( 1st and 3rd) has very high pressures and is prone to leaks.
Both are great transmissions when treated with respect and understanding, and are a marvel of engineers ingenuity.
Don
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Hi Don, I have a 59 Catalina with a hydra-matic and was wondering if you knew the fluid capacity of this transmission. Also I don’t see a drain plug anywhere. Do I have to remove the filler connection to drain the transmission?
Thanks!