[Safari Larry]

OOPS, after re reading, I found an error. End of second paragraph says

That results in 50% power transfer mechanically and 50% power transfer though the front planetary unit.

It should say

"That results in 50% power transfer mechanically and 50% power transfer though the front coupling.

[d2_willys]

Originally Posted by Safari Larry

OOPS, after re reading, I found an error. End of second paragraph says
It should say

"That results in 50% power transfer mechanically and 50% power transfer though the front coupling.

Larry, Don: Thanks for the enhanced explanation of the sprag clutch operation.

I personally don't like sprags for two reasons: 1) weaker than clutch paks 2) another element is needed to keep sprag from overrunning during Lo and S ranges.

From a simplicity point of view, the dual range uses straight forward thinking and does everything that the CC hydramatic does. And it does that with fewer components. This is where the CC unit is more complex. Less maintenance, but more complex.

The strategy must have stuck, as the turbo 400 uses sprags and overrun clutches too. Again, more complex than needed, as C4, C6, and Torqueflite units only have one sprag clutch and use a Lo/reverse band to hold in 1st gear.

One thing I can actually say about the various hydramatics is the durability in all of them, with possible exception of the Roto series.

Perhaps one of us could do a thread on the Roto series.

[U47]

Originally Posted by d2_willys

Larry, Don: Thanks for the enhanced explanation of the sprag clutch operation.

I personally don't like sprags for two reasons: 1) weaker than clutch paks 2) another element is needed to keep sprag from overrunning during Lo and S ranges.

From a simplicity point of view, the dual range uses straight forward thinking and does everything that the CC hydramatic does. And it does that with fewer components. This is where the CC unit is more complex. Less maintenance, but more complex.

The strategy must have stuck, as the turbo 400 uses sprags and overrun clutches too. Again, more complex than needed, as C4, C6, and Torqueflite units only have one sprag clutch and use a Lo/reverse band to hold in 1st gear.

One thing I can actually say about the various hydramatics is the durability in all of them, with possible exception of the Roto series.

Perhaps one of us could do a thread on the Roto series.

d2Willys, I'm sure Hydramatic division did design analysis with reliability and maintainability in mind on Roller and sprag clutches. If they didn't hold up Hydramatic division wouldn't have built them for nine years. I regards to Dual Range, after reading about the development of Dynaflow, Buick division flat out rejected Single Range and Dual Range Hydramatic as being too harsh and they really wanted a shiftless efficient automatic, so by 1948 their trans made it's first showing so I think CC was never considered.
Having a dad who drag raced, street raced, and also used our 59 Catalina for a daily driver, and then passed the car on to me to use as a street/strip car ( and you know how tough a kid can be on a car ) is in my opinion a testament on driveline durability. The bottom end of the engine,trans, rear ends ( 3, one street and two for drag racing) simply never let us down. As you said, the strategy stuck.

I would love to have a thread on Roto because this trans is the most misunderstood and feared automatic GM ever produced sans THM200. Sadly it's the first thing to go when someone resto's a 1961-64 Catalina, Ventura, or G/P. Evidently Oldsmobile had enough faith in it to use it in it's Complete line in it's model 5 and 10 versions. There are people in the Olds camp that do like them and they seem to last for them.

Don