My ‘55 Super 88 with the hydramatic transmission has a little “hitch in its get along” between second and third gear. Starting from a stop, first gear shifts to second pretty quickly, in just a few seconds. Then going from second to third I experience sort of a surge as it struggles to shift. If I let off the gas a little, it goes more smoothly. Then the shift from third to fourth is almost unnoticeable. I am aware that some adjustment can be made where the linkage attaches to the carburetor but I’m unsure of which linkage rod to adjust. The car has an Edelbrock carb so that might make some difference in adjustment procedures. Do I adjust the thinner rod in front or the thicker one behind? I also have been told that as little as a half turn is a lot.

 

Need some more history. Did this just start this behavior after the carb change?

The linkage going down to the trans #2 needs to be lengthened or shortened via that turnbuckle, #1. Is there only one turnbuckle? Or is there another one on the trans shift valve rod #2?

I'd disconnect the shift rod #2 and feel the amount of total travel it has. Compare that to the WOT travel on the carb. This will help make sense of which direction to go.

Snap a pic further toward the front of the car, #3. Need to see that area,

The road test will tell you which direction to go. Adjust a little bit at a time until you feel the difference, then go that way until the desired shifts are felt.
Count the threads and mark where it is now so you can get back to "home" if needed.
Count the direction and how many turns in/out were required to get the favored result. This will affect the up and down shifts.

 

Thanks for the quick reply. The carb was already on the car when I bought it, so nothing new there. You say to compare the travel to the WOT travel on the carb. I don’t know what WOT means. I’ve included a picture showing more of the engine area. I’m not sure but I think the rod you’ve labeled #1 is the one that goes to the gas pedal. I’ll check that out when I can get someone to step on the pedal and see what moves.

 

WOT = wide open throttle.

What transmission is in this car, factory Hydra-Matic 4 speed?
If in doubt, take pictures of the pan so we can see the entire shape of it and both sides of the case.
Is that weld I see on #4?
What is connected to #5?

Verify the carb secondaries are fully opening:
-Have a helper put the pedal to the floor (engine off)! With the gas pedal fully depressed to the floor, you need to look down the carb.
-Are all 4 carb butterfly's (Throttle valves) fully open? Im not talking about #6 & 7 air horn flaps. Im talking down inside at the bottom of the carb. #6 & 7 will need to be gently opened to see the throttle blades down inside the carb plate #8.

If the 4 flaps down inside are not fully open make the adjustment to #4 rod length to make that happen.
If in doubt disconnect all 3 things attached to the carb bell crank, #9, by removing the hair pin clips.Then hand operate the carb to see what WOT is... feels and looks like. Then make the linkage line up to WOT to mate with the holes on the bell crank.

Do this before adjusting the trans shift rod. It could be the overall WOT length is off. If that tests OK then adjust the trans shift rod.

Is that a factory 2 barrel intake manifold or a 4 barrel? I see a gap where the #8 arrow is.




Achieve WOT by adjusting this width

 

It probably got screwed up when that Edelbrock carb was installed.

 

I knew this wasn’t going to be an easy fix. Like they say, “If t was easy, everybody could do it.”
It is the original 4 speed Hydra-Matic transmission.
That is a weld on #4. The rod was worn almost in two so I had my neighbor weld it back. That may have altered the original length of the rod but the tranny had the hiccup between second and third before the weld was done.
I haven’t had a chance yet to check the carb flaps yet.
The curved rod connected to #5 goes back and connects to a bracket on the rear of the carb and connects to the rod with the weld.
It is a four barrel manifold.
The “gap” at #8 is not a gap. It is the black spacer between the carb and manifold.
We’ve been having severe storm warnings this morning so carb investigations will have to wait.

 

It's good you are getting to the bottom of the linkage adjustment with the carb change, but if your transmission is in otherwise operable condition and is flashing on the 2-3 shift there is no way around now adjusting the bands for proper operation. This is maintenance which was expected at specified intervals to keep the dual range H-M shifting properly.

There is one correct procedure specified for the front and rear bands, in manuals of all types. If you have a service manual for your car, read and familiarize your self with how this happens. Two factory tools are needed for the job, the rear band tool is a go-no-go gauge currently reproduced. Fatsco Transmission Parts has them in stock right now sold on ebay with eight currently available, Fusick may have them but has been out of stock on these as they are popular:

https://www.ebay.com/itm/186920408000?_skw=hydramatic+tools&itmmeta=01JXZ4C S0DZ57M2TXHQY6TDCJW&hash=item2b855313c0:gHwAAOSwlY pnm-SO&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1cMoY E3qpLyYnH7MoKUOeg39ukEOWizryMlTrqMJEP1OfMQWNQUeBu4 0r08OKcBA8scd%2BP6y8Gk3UioQ5mIBQBMuu5mVioFbOA9jym% 2F7aezt3qV8bzdITSdXZbzc1TIh%2B1W6f2ydn%2FYlRB7GrrF mFIQAjwWDjxCOUOH1FEB6rajkFLTTfHCGHlldeaGql4F6uCqZj %2B0KyHlV%2B8eLJuaQJDmyJuVfK6bIgysQc8CFKQPcuU7OyW5 EWgMKQ9cIVyYVcP22wdmx6lPWtC%2BOANIFOYAo9gncDu6nhS0 ueBq%2FgPVyw%3D%3D%7Ctkp%3ABk9SR76Qs-TvZQ

The front servo gauge is more difficult to find and is not reproduced. When they appear for sale on ebay they sell quickly unless wildly overpriced. You or your transmission man can borrow or rent one. David Edwards transmission parts used to rent them, but I would call Fatsco and see if they also rent them now. This is also a good opportunity to replace the transmission fluid and clean the inlet screen. There is a drain plug on the torus so don't forget that one. Be sure to observe the manual refill procedure, if you put all the specified fluid capacity in at once on refill some of it will end up on the floor.

Here are a couple of vids demonstrating the job on basically all H-M transmissions up to the Jetaway in late 1956 in Oldsmobile cars:

Front band - Rear Band -
Guys over the years want to tinker with these adjustments - Don't. Stay with the correct procedure and perform it at specified intervals which most owners who even drive their cars a lot or tow will not approach. If the bands have been properly adjusted recently and this problem still happens then move on to further troubleshooting using manual specified checks and tests. In a very high % of the cases these adjustments will accomplish cleaning up the shifts. Good luck work safe.

 

Thanks for that. I think I remember reading somewhere that the bands can adjusted externally - or did I dream that?

 

Well he is making the rear adjustment externally in the video - But it still requires the fixed gauge and the bottom pan off. It can be done in the car but the carpet has to come up for access to the hatch and adjusting bolt, assuming that remains the factory procedure in 1955. They removed the front external adjustment when production resumed after the 1953 plant fire. Adjusting the bands externally before that with the 'counting turns' tool without internal checks ceased to be factory recommended in mid-year 1952 as evidenced by a Oldsmobile service bulletin. You likely didn't dream that externally stuff. It's common cruise night and internet blather. CW

I almost forgot - Don't let anyone try to talk you in to taking the rear motor mounts loose and dropping the rear of trans to try to reach up and affect the adjustment without pulling the carpeting, the argument being the transmission is now clocked to the left in 1955 making the idea of that seem plausible. 1250# easy of engine and transmission swiveling on the single front mount is a a likely potentially fatal disaster.

 

So, there is nothing on the throttle linkage communicating with the trans?
I ask because I've never laid eyes or hands on a 55 Hydra Matic. I do see that cable and the rod off the accelerator bell-crank.

Does the Hydra Matic have something similar to a TV on a TH200 or TH700? or the kick-down rod on a TorqueFlite 727?

I had a 727 that short-shifted, flared and bump shifted. Solved that with the kick-down adjustment. It was much too far in one direction after a local wrench swapped in a used unit.

 

OK. I’ve had a chance to check for WOT. With the pedal tight against the floor, there is no movement in the “flappers” down inside the carb on the back two ports. There are no external parts on the carb that make those flappers move - even with all the linkages removed. I do not see any of those flappers in the front ports. The first picture is the flappers resting position - about half open - and that’s where they stay. The second picture is the flappers fully open being held in place with a screw driver. Since they aren’t moving, I have delayed adjusting the length on any of the turnbuckles awaiting further guidance. I have visited with my usual mechanic but he has no experience with this carbure


tor.

 

I forgot to mention that there is a triangular piece of metal in the right side of the carb that moves when I open and close the flappers. I assume that is a counterweight but there is no external linkage on that side or anywhere else that opens the flappers.

 

Yes, there is linkage going to the tranny. I haven’t adjusted any of that until the carb issue is resolved. I have no idea what a kick down rod is or a TH200 or TH700?

 

Guess i will be the bad guy here and ask,,,,,,,,,,,do you have a 55 Olds Shop Manual? I see that the carb was changed, but the original linkage appears to be all there except,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,it looks like the rod going to the firewall was cut, or? and then rewelded. No matter what,,,,,,,,,,,,,,,,,,,,,,,,,,,,,it looks like it could be made to work. Be careful adjusting something and then adjusting something and then,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,That is what gets people deeper in trouble. Look at these pictures and maybe you can figure a good starting point. And as for the original question on throttle pressure adjustments. That is done in your second picture arrow #2. Don't give up, you will get it.

 

Yes, I have a shop manual. When I took the carb off to clean it, I put it back together using the instructions in the book. The car has had the shifting problem since I bought the car a few years ago. I took the car to a transmission repair shop and it was partially disassembled there. The old mechanic there was very familiar with this make and model. He removed and cleaned the pan and put it back together. He thought it needed an overhaul but I couldn’t afford it at the time. He didn’t think continued driving would hurt it any, so that’s what I’ve done. I suspect that the Edelbrock carb is just enough different that the specs in the book are a bit off. I’ll fiddle with the adjustments and see if I can make it better. If I can’t, oh well, it still looks great.

 

Well that's a little more helpful information. That throttle pressure rod would be a good starting point and as someone stated earlier, just a half turn to a full turn at a time. Just remember making that rod longer will make it shift early and lazy. Shortening will make it shift longer between shifts and maybe snap your neck if done to far. I would do just like you are doing and drive it. Those old Hydros are fairly Bullitt proof. A can of trans X might help somewhat.Good luck Dave.

 

Issue resolved. Thank you to all who contributed to this post. I followed the advice to shorten the linkage going to the transmission (#2 in the second photo above) a 1/2 turn at a time. It took 5 complete revolutions to get it where it is now. There is a small bump as it shifts from second to third and a little more noticeable shift from third to fourth than there was before the adjustments. I may not have it at the “sweet spot” yet. I thought I’d drive it a few days and see how it goes. If anything, I’ll shorten it another 1/2 turn or so. I don’t want to mess with it too much to the point where the other gears begin to have problems. The only other issue I still have is a little play in the gas pedal. You have to push down a bit before anything happens. Pretty sure tightening up the linkage to the carb will take care of that. Anyway, thanks for the help.

 

Glad it is resolved - enjoy your car - CW