Quote:
Originally Posted by Safari Larry
I just updated the Dual Range Hydramatic Power Flow document. I changed wording where I said the "transmission is locked". That could be interpreted as the transmission is locked up but I meant it was locked into purely mechanical operation.
I also added some info on the Wikipedia Hydramatic description referenced in my document. After additional contemplation of the power flow, I now believe there is incorrect information in that article about the dual range.
In my post above where I say
I should have said "...was locked into purely mechanical operation in third/fourth gears ...". We don't need any more confusion! |
Larry: I really enjoy talking about the grand-daddy of them all, the hydramatic. IMO this IS the finest automatic ever made! For the era of the design, this is a masterpiece created by a team of geniuses. Luke Beach, Earl Thompson and the rest of the design team will always be in my heart and mind, as I have been a fan of the hydramatic for 46 years. I originally started to gain automotive knowledge in high school and was fortunate enough to have a friend and a neighbor that had hydramatics. I started reading about them as a freshman and could not get enough books to keep me happy. After getting my drivers license, my neighbor had a hydramatic that was just rebuilt and was a R54 hydramatic, which was installed in a 53 Olds 98. My neighbor said, take it out and it is all yours. Well my friend and I yanked it out. I later installed it behind a 60 Olds 371 and installed in a 62 chevy Nova. Fast was not the word for that car. It was blazing fast, and the hole shots were unbelievable. One of my other friends said he had never seen a car launch like that did. I told him it is all in that transmission! Gears!!!!
Well now I am almost 60 and still messing with those transmissions. Having about 15 of them around the house, along with having them in Oldsmobiles, Lincoln, Hudson, and even have one from a Willys Bermuda attached to the Continental six.
Reading your post made me understand the lock up feature more clearly. 3rd and 4th gear does do the torque splitting of the rear planetary, but you are correct, that the coupling provides a means of slip, not much, but some. Perhaps it was there to safegaurd the transmission from blowing up on a quick brake lock at high speeds, who knows. I am basing this on the super and lo range safeguards when the TV and governor pressures match, the transmission will shift up to save engine, etc.
Who would have thought that a valve body the size of a pak of cigarettes could do all the things that the hydramatic does? Other novel ideas: reverse blocker, reverse park pawl, running the engine power thru the front planetary to reduce creep, automatic shift up in super and lo ranges. I would call this invention the 8th wonder of the world.
Only issue the hydramatic had were the mistimed 2-3 shifts, and on the early single range hydramatics, the reverse mechanical clutch. Oh, and the fact that instead of fixing the few issues it had, GM went to work on the Jetaway. Sorry, but sprag clutches and dump and fill couplings are not my favorite types of transmissions. Accelerotors too.
But then transmissions like dual path and Flight Pitch 3T transmissions do have my interests. The 50's and 60's were the good times.
Keep the hydramatic articles coming! Thanks