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My 1956 has a slant pan Hydra Matic transmission. I've been experiencing some shift issues from 2nd to 3rd. I dropped the pans and found a lot of black sludge in the bottom of the pan. I pulled the valve manifold off the side of the transmission and tore it down. So far all I've found is some more of the black sludge in the manifold. I'm cleaning everything in my ultrasonic cleaner.
I'm trying to get this done and back together before the weather warms up here in Minnesota.
I'll keep you posted on my progress.
Admittedly I don't know that much about your transmission. I serviced a couple in my Dad's cars back in the later 1950s/1960s. I've read several threads over a couple years. I saw a used (original) 1956 Hydramatic Transmission Service Manual for sale last week and here's a thread about a 1956 Hydramatic - not 100% if same as yours. You can search for the service manual there most likely are others out there. Good Luck.
Did you clean the oil pickup screen circled in the pic below?
Cleaning everything up, and a fluid change may solve your problem.
If not, a band adjustment may be in order.
The procedure will be in the shop manual or the Hydra-Matic manual.
In 1956 Oldsmobile used two transmissions, the Hydra Matic in the 88 and the new Jetaway in the Super 88 and 98. The big difference between the original Hydra Matic and the Jetaway is there is no Park position in the Hydra Matic and there is a Park position in the Jetaway.
I have the Hydra Matic which is also is referred to as the slant pan because the bottom pan is slanted.
The 1956 manual only has information on the Jetaway, I have a 1955 manual that covers the Hydra Matic.
When I dropped the bottom pan the screen was quite clean. It has some particles on it but not enough to affect the operation of the transmission.
I have completely torn down, cleaned and reassembled the manifold. I did not find any evidence of a problem.
It appears the problem is either in the adjustment of a band or a worn clutch.
If what I've done does not cure the problem it will most likely require removing the transmission in order to rebuild it.
If the RPM flashes up between 2 and 3 it is band adjustment. This was service the designers expected the unit to receive at regular intervals, many have never had it even once. Both bands adjusted with 'internal' method using the service tools for this purpose, outlined clearly in service manual. But servicing the fluid and cleaning the screen is a excellent idea. Good luck ~
Most likely your 2-3 shift will not be a smooth as all the rest, so don't get too upset if it doesn't feel a smooth as the 1-2 shift or the 3-4 shift do to transfer of fluids. These transmissions will take years of abuse before he bands give out, so you may luck out with a fluid change. Tedd
If the RPM flashes up between 2 and 3 it is band adjustment. This was service the designers expected the unit to receive at regular intervals, many have never had it even once. Both bands adjusted with 'internal' method using the service tools for this purpose, outlined clearly in service manual. But servicing the fluid and cleaning the screen is a excellent idea. Good luck ~
If you do not have the service tools for the band adjustment, there is an external method performed with the engine running that only requires ordinary hand tools. Motors manuals provide a detailed description of how this is done. Also make sure that the TV linkage is adjusted properly. If the band and TV adjustments do not improve the condition, you may have deteriorated piston seals or sealing rings.
Hey coldwar. As said before. I’ve got no 4th gear but when I’m in neutral with E brake on and I rev the engine long enough or hard enough the car jerks as if it’s try to go into gear. Already tried the gauge tester and every adapter to try and put it on but no luck. All other gears are smooth and fine. Any ideas on my no 4th gear issue?
