1956 Jetaway will not engage

[carguyblack]

(Continuing, sorry)
If you'd like, PM me and I can send you the info on my transmission expert. He recently retired and sold his shop of 50 years and now runs a vintage hobbyist transmission shop where he lives doing it just for fun. He's amazing and knows every quirk and service bulletin updates on these things since the late 50's. Weird as your symptom is to you and I, I'll bet he's encountered it already sometime.  Let me know.
Chuck

[carguyblack]

Shucks, forgot for a minute you're in Sweden. I was hoping to connect you two by phone. Any chance that idea still might work for you?

[dn010]

Note that you might get some forward creep if you give the engine some throttle in neutral. Reverse creep in neutral shows something is sticking so while you can try it again tomorrow, I think ultimately, you'll be looking at removing and opening up the valve body.

Also remember, whatever particles are breaking loose, are going right back into the filter so you should clean it out each time you are in there.

[Bronze]

Evening guys,
Yeah, I agree. I will need to take the valve body out eventually. I'll just put on one more show for the neighbors

[Lexi]

Martin that is hilarious. One more show for the neighbors, LOL. I don't know how proficient you are with these transmissions, but if you have serious concerns, I could try and copy the cleaning of the control valve instructions in the 1956 Hydra-Matic Manual for you. Can't remember the page count, would have to be done in several posts, and not particularly looking forward to doing it. But will give it a shot if you are worried about this job. Clay/Lexi

[Roger Zimmermann]

If you have the shop manual, Section 12 covers the transmission and there is a segment on the control valve. There was also a "Hydra-Matic Transmission Service Manual", (Paul Marsh Company, Detroit, Michigan, 1956, # HM 1001). Details Hydra-Matics 1949 - 1956. There is a section in that manual that addresses the "Disassembly, Cleaning, Inspection, Repair, Assembly and Installation of Control Valve Assembly".

Don't forget that this manual will not apply to the '56 Hydramatic as installed into Cadillac models. On some Oldsmobile and Pontiac cars, the first Hydramatic generation was used till 1956.

[Lexi]

Yes, I believe you are correct Roger. Much of the material seems to end with 1955, but there are some 1956 notations in the manual as well. It seems to be a generic type instruction book. The disclaimer in the manual for this particular part is that while not all control valves will look the same, the instructions printed in the manual says that a "typical valve body" is shown, and that readers "...will be able to overhaul any valve body" using this manual. At least that is the claim. Haven't taken one apart myself, but if you have and if you also have seen this manual, how close was it to the control valve body for 1956 Cadillac? My own thoughts about this manual for 1956 Cadillac application is that it would generally help, but will be hit and miss with some applications. Clay/Lexi

[Roger Zimmermann]

I don't have this manual. In my opinion, the repair instructions in the shop manual are sufficient for this task.

[Bronze]

Hi Again,
Well, today's show is over and there was no further improvement. So yes the valve body will have to come out, but that will probably be in the spring. I don't have a heated garage and have done enough on my back on cold concrete for this time around.
Thanks so much for the offer Clay but at this point i feel i can do it with the shop manual...eh and probably some advice from this forum At least I have now read through the Hydra-Matic section of the shop manual and start to get an idea of how the internals work...

[Bronze]

Hi Again, I hope it is ok to resurrect a half year old thread when the same topic continues.
I have now jumped back to the Trans that would not engage. Tried to take the Control valve body out today. took out 6 screws i think and it dropped down about half an inch but no more. it is flexing on the Channel Plate Case Spacer. It is like one end of the valve body is stuck to the plate and the other end of the plate is stuck to the trans casing. Is the plate attached to the case or valve body or just "slid in between" and fixed by the screws holding the valve body to the trans? Is it the plate just "glued" in place by old gunk?
Any advice appreciated as i really don't want to use force to get the plate separated from the transmission case...

[Bronze]

And now i just realized there is a tab on the narrow end of the Case spacer plate with a bolt hole in it. Is it one of the servo bolts that goes through that tab? do i need to remove the servo first?

[Roger Zimmermann]

The accumulator must be removed to free the valve body. It's attached with 3 screws; heads are for a 9/16 wrench.

[Bronze]

Thanks Roger, I started to suspect that. Could not find anything in the workshop manual on removing valve body and Accumulator. It just says "remove" and then goes to describe how to take them apart. So i ordered the service manual recommended by Clay

[CadillacFanBob]

Thanks Roger, I started to suspect that. Could not find anything in the workshop manual on removing valve body and Accumulator. It just says "remove" and then goes to describe how to take them apart. So i ordered the service manual recommended by Clay

@Lexi Clay please could you post a picture of the cover of the service manual you recommended?

Thank you in advance,

Bob

[Bronze]

Quick update: Valve body and Accumulator/Servo is out. Cleaned up the Valve body. No stuck valves but pretty dirty inside, dirty enough that I think it is possible the ATF has not been able to circulate properly. When I did the Shift valve body I found out the Neutral clutch valve and spring was missing. Spent some time scratching my head wondering if I had misplaced it until I found a post by Jose 10 years ago with the same problem. He discovered that that valve was omitted with the change of some clutch material. so I guess I am ok without that valve. Roger, you seem to know these trannys inside out. what do you think?
Now going to do the servo/accumulator. I think this may be the real culprit. About 10mm of hardened gunk on top of the servo piston. I think it is thick enough to limit the travel of the piston and in that case I guess it would not put any real pressure on the band and that would explain why the car never goes into gear, right? Thanks everyone for all helpful input so far!

[Bronze]

Bob I think this is the book Clay mentioned. At least I ordered a copy of it from eBay.
https://www.ebay.com/itm/185443644299?hash=item2b2d4d738b:g:M7oAAOSwpj9ikX3X

[Roger Zimmermann]

In my shop manual, I have a notice that the neutral clutch valve and the spring were deleted.
The band is only used in Low. You have certainly another issue for the reverse.

[CadillacFanBob]

Bob I think this is the book Clay mentioned. At least I ordered a copy of it from eBay.
https://www.ebay.com/itm/185443644299?hash=item2b2d4d738b:g:M7oAAOSwpj9ikX3X

Thank you Bronze, that is what is was looking for with the photo on line.

Bob

[Lexi]

Bob I have been away on a vacation so just saw your post for that Hydramatic manual image request. Yes, the links provided show the book that I referenced, so looks like no need for me to post a picture of it now. Just did not want to think that I ignored your request. Clay/Lexi

[CadillacFanBob]

@Lexi Thank you for the reply, I never thought you would ignore me or anyone, because you are a good person.


Bob