Register now to get rid of these ads!

55 Pontiac Hydra-matic questions ??

Discussion in 'The Hokey Ass Message Board' started by Toast, Feb 21, 2014.

  1. Toast
    Joined: Jan 6, 2007
    Posts: 3,886

    from Jenks, OK

    I tried this before and was getting some good response and it was deleted. Ryan told me it was a technical error, so I will try again. :)

    I have a 55 Pontiac with the Hydra-matic trans, last year for this version. When i drive it hot or cold it waits too long to shift into at least 3rd and 4th. However if I let off on the throttle just a little it shifts right away. Also when it is warm, when it down shifts into 1st when coming to a stop or making a slow turn it hits so hard iit almost throws me forward! I have been told there is several adjustments but don't want to mess with it if I don't have a clue.

    Oh, and for you "do a search" guys, I have and there is lots of Hydra-matic info on here that never addresses this issue.

    Any constructive help would be great!
  2. Poncho60
    Joined: Jan 23, 2011
    Posts: 103

    from N Illinois

    I suggested going onto the Performance Years (PY) Pontiac site, and checking out the forums. If you sign up for the site you can then do a search. I suggest specifically going to the 61 and older forum. Lots of people with knowledge there and this has been covered before.
  3. saltflats
    Joined: Aug 14, 2007
    Posts: 7,001

    from Missouri

    I have a 1960 motors manual that show the adjustment for the throttle control I can scan it when I get home tonight.
  4. backyardbeliever
    Joined: Sep 15, 2006
    Posts: 298


    I do believe all your symptoms are due to your throttle pressure being too high which is controled by the adjustment of the linkage that goes up to your carb (Adjusted by bending usually,there is a special tool that does this).
    Get a manual and read about it.
    BTW really great trans it was best of all the years
    Last edited: Feb 21, 2014
    Register now to get rid of these ads!

  5. Toast
    Joined: Jan 6, 2007
    Posts: 3,886

    from Jenks, OK

    Thanks guys, really good suggestions, I also found a 55 pontiac Hydra-matic manual on the auction site, looked like a good resource. I know these are super strong transmissions and its not slipping so I am sure it can be adjusted, just don't want to screw it up by doing the wrong thing.
  6. backyardbeliever
    Joined: Sep 15, 2006
    Posts: 298


    it will slip a little as the throttle pressure comes down when you are adjusting it . you have to find the "harmony" point in the adjustment. Its not just that its a strong trans but its "The One" as far as racing and gasser stuff goes. special front planetary
  7. justpassinthru
    Joined: Jul 23, 2010
    Posts: 178


    I am going to assume you have a Single Range Hydramatic in your car. (The one with a side pan on the left side). The band adjustments are very critical on this model trans as well as the throttle pressure adjustment. Here is a procedure for adjusting the bands that works quite well. One note is some of the really late model Single Range transmissions did not have an external front band adjustment, it was internal. So some or all of this procedure may not apply.
    Bill ​

    External Hydramatic Band Adjustment​
    For this job you will need some wrenches and a good, accurate tachometer. Making these adjustments without a good tachometer is almost impossible. Here is the step-by-step procedure:
    1. Block the wheels and set the brake.
    2. On cars so equipped, remove the plate that covers the access hole in the front floor pan. This plate is located to the left of the transmission hump. if you do not have this plate, the bands of your transmission are only adjusted internally. This requires special tools and should not be attempted.
    3. Without the special band-adjusting tool you may have to work partially from underneath the car. I would put a good jack stand under the rear wheels and not rely on the brake to hold the car in place:
    4. Warm up the engine by running it neutral range.
    5. Connect the tachometer and set the selector for operation in either the six or eight cylinder setting.
    6. Set the transmission selector in Drive. For 1950-51 Oldsmobiles put the selector in Low range.
    7. Adjust the carburetor idle screw until an engine speed of 700 RPM is reached
    low we have to deal with the band adjustment screw and its locknut. The easy way to do this is to use the band-adjusting tool J-26881, as described in the shop manuals. In talking to old-line dealership mechanics, they are unanimous in saying that their bosses bought very few of the special tools recommended by Oldsmobile. J-2681 may have been an exception, but let's take a look at what the tool is supposed to do and then figure a way around it.
    The tool consisted of three parts. (1) A tube about ten inches long with a 3/4' hex socket at the bottom engaged the band adjustment lock nut, and a large handle at the top gave the effect of a .ratchet handle: This loosened and tightened the lock nut. (2) a shaft ran through the tube and this shaft had a socket at the bottom which engaged the square-head band adjustment screw. A 3/8" twelve point socket will turn this adjustment screw. These two parts allowed the mechanic to loosen the lock nut, make an adjustment, and then hold the adjusting screw while tightening the lock nut so as not to upset the adjustment just made. This seems a very simple function, and it would be if you were doing it with no front floor in the car. It is the limited access through the access hole that causes a problem.
    The third part of J-268 1 was a Veeder-Root type counter, with a reset knob to allow the mechanic to reset it to zero. This device is like the odometer on the dash, and with each turn of the inner shaft in adjusting the band adjustment screw, this thing counts the turn. The assumption was that a mechanic could not concentrate on his task sufficiently to count the turns himself. The third part we can easily ignore.
    Lacking the J-2681, there are a couple of approaches around the problem. Loosening the lock nut with a 3/4" socket is the first step, and making the adjustments with a 3/8" socket is the second step. Tightening the lock nut while holding the adjustment screw from turning is probably a two-person job. Cane person could hold the adjustment screw while the second tightens the lock nut with a %" crow-foot on the end of a ratchet extension. An alternative is for the lock nut to be tightened from below the car while the adjusting screw is held from above.
    For those who really like to deal with tools, take an old 3/4" socket and cut the top off. Weld a 10" long section, of steel pipe on the top, and weld a steel rod or angle a foot or so long across the side of the tube, near the top; to serve as a handle. Make it so that a 3/8" socket on an extension will fit through the tube and the cut-off 3/4" socket and you are in business.
    Now we can return to the adjustment process.
    8. Loosen the lock nut on the front band adjustment (the one closest to the engine) while holding the adjusting screw.
    J. Turn the adjusting screw counterclockwise until the engine speed goes from 700 RPM to between 900 and 1,000 RPM. The drum of the front planetary is now spinning freely. If the engine speed does not increase, it is an indication that the band is slipping under normal driving conditions and internal inspection and adjustment is required.
    10. Now slowly turn the adjusting screw clockwise until the engine speed drops to 700 RPM .
    11. Repeat the above procedure three times. The object in loosening and retightening the screw is to locate the exact point at which the bad stops the drum from spinning.
    12. When you get back to the 700 RPM the fourth time wait at least 30 seconds.
    13. If the engine speed increases at all, turn the screw clockwise 1/10 turn until he engine speed stays at 700 RPM for at least 30 seconds. This indicates that the front drum is being firmly held.
    15. For very early Hydramatics, the lock nut is tightened with the adjustment screw at this setting, as described in step 17 and step 16 is skipped.
    16. For 1949-51 units, while holding the lock nut stationary, tighten the adjusting screw exactly 5½ turns
    For 1952 units tighten the adjusting screw exactly 6½ turns. Here it is best to check the shop manual for your car to get the proper adjustment.
    17. Hold the adjustment screw stationary and tighten the lock nut. This nut should be torqued to 40-50 foot pounds.
    16. Recheck for a 700-RPM tachometer reading.
    Repeat this procedure for the rear band adjustment with two exceptions. Make the adjustments with the transmission in neutral. After getting the 700-RPM to hold steady for 30 seconds, tighten the adjusting screw exactly two complete turns. Then put the transmission into Drive range and tighten the lock nut while holding the adjustment screw in place. This lock nut should be torqued to 40-50 foot pounds.
    With the transmission still in drive, reset the carburetor idle adjustment to the specified idle speed, which is 375 RPM for the early Rocket engines.
    Never flush the Hydramatic transmission- If the fluid seems bad, fill and refill several times, letting the fluid come up to operating temperature each time before refilling.
    1. Clean around the fill hole, which is under the floor pan on the right side of the transmission prior to 1951, and through the transmission dipstick from 1951 on.
    2. Pour eight quarts of the proper fluid into the transmission, using a filler funnel.
    3. With the engine in neutral, run it at fast idle for 1½ to 2 minutes.
    4. Then, while running at slow idle, add enough fluid to bring the level to just below the "L" mark on the indicator.
    5. Run the engine at fast idle for three minutes to bring the fluid to operating temperature.
    6. The at slow idle add fluid to bring the level to the "F" mark.
    7. With the engine idling and the fluid warm, check to make sure that the transmission is not overfilled. Be careful not to overfill the transmission, as this will cause the fluid to foam.
  8. 53chevy
    Joined: Mar 5, 2001
    Posts: 1,509


    Good, info here, check your TV cable. This is the cable that connect to your trans to your carb. Adjusting it can dial in your shift response. I have a '60 Pontiac Ventura with the Hydramatic trans. Tranny John here in SoCal works on these trans and is a world of knowledge. Google his name or call Masterson Customs shop off Atlantic blvd in SoCal.
  9. RDR
    Joined: May 30, 2009
    Posts: 1,179


    X2 on Tranny John for sure!
  10. Toast
    Joined: Jan 6, 2007
    Posts: 3,886

    from Jenks, OK

    Hey, Thanks guys, I have a manual coming and a lot of HAMBers good info to start studying.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2013 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.