1956 Cadillac Transmission shift timing?

[carguyblack]

Could anyone give a knowledgable response to this question: My newly rebuilt transmission on my 56 Cadillac seems to shift early. It goes through the first 2 gears fine, drops into the 3rd gear at about 10-13 mph but then almost immediately goes into the final gear somewhere in the 14-18 mph range. When I gently push on the gas on an incline, it stays in the 4th gear and torques it's way along. If I punch it under load, it drops into a lower gear smoothly and shifts later as it should, but when just gently accelerating, the phenomena I describe of premature (?) shifting occurs.
Can this be adjusted outside of the transmission or is it a valve issue internally? I can live with it, but I'd like to delay the 4th gear more if possible without spending any more money on it!
Thanks for any suggestions. Chuck Dykstra

[Dave Shepherd]

The  tv rod must be adjusted per shop manual specs, very important on the Hydramatic.

[J. Gomez]

Chuck,

I second Dave's comments.

The only adjustment outside the transmission will be the TV rod which is describe in the Service Manual. The manual indicates a possible cause for up-shift or down-shift problems could be related to the throttle linkage adjustment that could affect the manual control valve. 

Good luck..!

[carguyblack]

I pretend to be a pretty good fixer, but I don't want to take a chance on me regarding the transmission. Is this something that a current transmission shop could do correctly for me? Or do I need to find a 78 year old  transmission guy in a retirement home who knows about these things?
I thought I was something special just to get the trans back in the car by myself! I'm more of a horse than a fine tuner, I'm afraid. If you all tell me I can and should do it myself, I'll give it a shot.
Chuck

[Otto Skorzeny]

Chuck, read the entry in the shop manual. It's very straight forward with no special equipment needed.

[Carfreak]

Chuck,

Are you a West Michigan Region CLC member?   Perhaps someone in the group has experience and can help you out or direct you to a shop in the area that can make the adjustment if you don't feel comfortable using the shop manual to do it yourself. 

[carguyblack]

"Ask not what your country can do for you, but what you can do for YOURSELF"
Good quote, but the problem is that I don't trust myself!!  
Thanks, Forrest. I'll re-read it again and give it a shot.
By the way, could I be wrecking something by driving it not adjusted properly?

[Otto Skorzeny]

No, not really. You said it's shifting into all gears so it's working.

Proper TV adjustment is all it needs.

[Caddy Wizard]

I find it useful to first make sure the engine is in perfect tune and that the vacuum advance unit is working correctly (not leaking vacuum thru the diaphragm).  Having said that, the description in the shop manual of how to adjust the TV rod is pretty easy to follow.  I followed the manual and got it right with no prior experience with this style of transmission (although in candor I was a professional mechanic earlier in my life).

Art

[J. Gomez]

Chuck,

Just for clarification you mention a “newly rebuilt transmission..”!

Was this done by a transmission shop old shop new shop? And was this a full rebuilt, all clutches, pressure plates, gaskets, etc, etc?

Did the transmission exhibit the same behavior before the rebuilt?

The other possible problem could in the shift valve; there are two springs that look very similar the 2-3 valve and the 3-4 valve springs, if these are reversed it could cause the behavior you are experiencing. Just a thought..!

By the way, could I be wrecking something by driving it not adjusted properly?

Possible abnormal wear of the clutches…! 

[carguyblack]

Thanks again to all who helped me through this once again! I finally adjusted all the linkage and the TV rod and I believe they are all where they need to be. I have a passing gear again, the indicator needle lines up, the steering column position indents hold and the trans shifts ok. I still think it shifts early into 4th but after shortening the TV rod even more with no change, I must have something going on internally. As it operates seemingly fine at this point, I see no need to go deeper into this unless some of you think I should. Back on the road again! Chuck

[Otto Skorzeny]

It may work itself out after you drive it a while but since you adjusted it and the passing gear works I think your transmission is probably just fine.

[carguyblack]

Just another follow up on this. Happened to stop in to an old-timer's transmission shop who is a friend of mine to ask him to put his eyes on this. He found that I still had not shortened the TV rod enough and he took it in another 3/8 to 1/2 inch and what do you know, transmission is fine with no internal quirk to worry about! Jose, you were right again but I was gun-shy in cranking that TV rod in too much. Maybe nobody else has these issues, but just in case, I thought I'd let you know the "rest of the story" if it helps anybody else. Still have a slight adjustment to make on the throttle linkage as I don't get a strong downshift when I punch it. This same gentleman told me to lengthen the throttle linkage to push the gas peddle out more. I did this and my idle speed went way high. I tried to back the idle adjustment screw down but that didn't lower it enough. So I turned the linkage back in a couple of turns and it seemed to help. Did I do this adjustment ok or is there something I should have done under the car that I didn't see? The low idle when fully hot seems to race a little now and I need to kick it down periodically to lower it. It is not hanging up on the high idle tang. It does kick down to the correct idle but that can't be right.
One adjustment always seems to affect something else!

[J. Gomez]

Chuck,

As you know there are several rods that can be adjusted, the TV rod, the throttle control rod from the carb and the one going to the pedal and finally the throttle return. Any minor adjustment tweaks made to either one of these it will affect the others.

Besides the steps from the manual under the Fuel and Exhaust, and Hydramtic sections there are also a few tips in the Servicesman that could help in getting these set properly.

Accelerator to carpet clearance.

http://www.modifiedcadillac.org/documents/1950s/1956/1956%20Cad%20Serviceman%20No%206%20Jun%201956/tn/1956%20Cad%20Serviceman%20No%206%20Jun%201956-3.jpg.html

Alternate adjustment for throttle return.

http://www.modifiedcadillac.org/documents/1950s/1956/1956%20Cad%20Serviceman%20No%206%20Jun%201956/tn/1956%20Cad%20Serviceman%20No%206%20Jun%201956-2.jpg.html

Any of these adjustments should not force the rods to either push or pull the throttle lever at the carb. I think you are almost there with the fine tuning, just a matter of getting those rods set correctly.

Good luck..!