1955 Transmission Shifting Hard....A fix?

[55 ledsled]

I have a 55 Cad that I put a 54 engine into using the original 55 trans and it seems to shift really hard in all gears. Any ideas?

A little background on the Trans:
I replaced both front and rear main seals, had the pan off and I cleaned the filter. The fluid smelled good and was still a good color pink and I did not see any metal shavings or anything else of concern.

After installing the trans and motor starting the shakedown process we all enjoy, the trans kept shifting too soon and no amount of adjustment on the TV rod made no difference. So I looked into it some more with the help of some of you fine fellows, and found out that I had the problem of the TV rod connection located inside of the transmission valve body that was broken loose, this happens because of the thin metal and poor spot welds. The lever was not pushing the button on the valve body to perform the shift. I guess many have seen the arm inside break off at the spot welds (pretty common I guess). I was able to line it up and put a couple quick welds fixing it while it was still mounted in the trans. (I posted photos as well on the forum).

After playing with the TV rod adjustment on the carb while driving up and down the backroads, I was able to adjust the length between shifts to be reasonable and I am still playing with it to get it perfect. It still has a bit of problem downshifting back into first when coming to a stop sign as you almost have to be close to a full stop for it to shift. Again, I am still playing with the TV rod.

My main issue is that it shifts very hard on every gear, like to the point that it will snap back like your driving the 1/4 mile with a big block. Any ideas of how to fix this? Does anyone know if there are other adjustments that could be done on the band adjustment area of the trans? Any info would be helpful.

[Bob Kielar]

By no means I’m I a transmission specialist. I do remember when I first got my 55 that they had the idle set at 625 rpm so it wouldn’t have the gen. light come on. When it would down shift into first it would almost put your nose on the dash. I adjusted the idle to 425rpm in neutral and in drive it’s 400rpm. Had to tinker with the tv rod now it shifts much smoother.

Keep Cruzin,

Bob Kielar

[walt chomosh #23510]

Adam,
  I've been driving a 1955CDV for 20 yrs now and my shifts have never been smooth. Another experienced Hydromatic owner told me that rough shifting was the norm for these transmissions. (shifts on mine are sometimes smooth and sometimes rough depending on throttle given it seems) I CAN say for sure that the TV rod adjustment is critical for reasonable shifts.....walt...tulsa,ok

[Cadillac Jack 82]

My 55 doesn't shift hard but sometimes its noticeable.  My 57 shifts smoothly to the point you don't even feel it.  Roger Bentley said something that Cadillac did that because people complained that they couldn't feel the shifting.

[Roger Zimmermann]

My 55 doesn't shift hard but sometimes its noticeable.  My 57 shifts smoothly to the point you don't even feel it. 

The '55 and '57 transmissions are quite different. Don't compare them.

["Cadillac Kid" Greg Surfas 15364]

Seems like GM trades the indestructible (WW 2 tanks)40-1955 Hydramatic for the smoother shifting, untried and (initially) trouble
Prone “jetaway”
Greg Surfas

[Caddy Wizard]

The 1-2 and 3-4 shifts should be very smooth.  The 2-3 shift will be more noticeable and firmer.  If they are all harsh, something is not right.  Most likely culprit is the TV rod adjustment.  Follow the steps in the Shop Manual -- ALL of the steps.  Follow each step to the letter, even if it seems stupid.  It will probably fix it.


The bands could also be adjusted too tight, which would prevent the transmission from slipping at all during the shift.  That could cause a very hard shift in all gears.  But typically, one band (not both) is adjusted too tight. 


Because it is shifting hard into ALL gears, I suspect the TV rod adjustment, primarily.

[Caddy Wizard]

Adam,


Any luck?


Art

[55 ledsled]

Sounds good everyone. Thanks for your input. I have not had the time as of yet to do some more adjusting. I also think it's the TV rod or some slow valve internally. It seems that gears 1 to 2 seem to shift a bit early and then you need to get the rpms up for shifting into 3rd and 4th stretching out the RPMS. I need to force it to shift by letting off the gas pedal a bit especially for 3rd and 4th. I just don't like the "put your nose into the windshield" shift feel lol. It also seems that I almost have to come to a stop for the trans to downshift back into 1st which I understand but it seems a bit slow.

Another thing I noticed at a car show the other day was when I was at idle for a bit waiting in line for my registration, I went to stop and reverse into my parking spot and the car seemed like it didn't have enough power to back up or like it was hesitating but still sounded like it was running OK. I did notice this happen once before.

[35-709]

"Another thing I noticed at a car show the other day was when I was at idle for a bit waiting in line for my registration, I went to stop and reverse into my parking spot and the car seemed like it didn't have enough power to back up or like it was hesitating but still sounded like it was running OK. I did notice this happen once before."

That could have been the onset of vapor lock.