Technical 1956 Hydramatic "Jetaway"

Hi,

last night I was cruising with my 56 Olds enjoying the nice evening - stopped at a gas station and as I pulled away after topping up the tranny didn't shift into 2nd gear anymore...

All that worked was the 1st gear.

I checked the oil - all fine.
Reverse working fine as well.

Any of you experienced guys know the problem and a quick fix?
I live in Germany and finding a replacement over here is no real option.

Is a transmission repair easily done - as I am rather skint right now.

Thanks for your help.
Jan

 

Here's a rebuild kit, not cheap. Could be a simple linkage adjustment at engine, have you a shop manual?

• Hydramatic has no separate Park (P) position, reverse (R) is park when engine is turned off; or
• If there is a Park (P) position, the transmission is a Jetaway or Dual Coupling Hydramatic. http://www.autotran.us/hmkits1.html

 

I do have the shop manual and it has a P position - so it is indeed the "famous" one-year-only Jetaway hydramatic...
It is unfortunately no external misalignment of the linkage - in either position it does not upshift (D, Lo, S) ...
Also found a rebuild kit at Fusick with a similar price tag - but if anyone had experienced such a malfunction before and knew a cheaper trick to get it going again I would surely try this first...

 

can a 55 hydra be retro-fitted? I love the 56, but do not like the Jetaway.

 

Possibly yes - not sure if an adapter would be required, the length of the drive shaft matches and the linkage needs to be altered - but the main issue would be that a 55 hydra is equally hard to locate here in Germany, I'm afraid.

The question is more related to is it possible to do the overhaul myself or to stay away from this as it is known to be a job for only experienced transmission specialists - i.e. high costs that I cannot bear right now

 

Didnt see that. Best of luck.

 

Just my 3.5 cents but Did it Shift before You put Gas in it
& top off the Tranny..???

Just asking

Live Learn & Die a Fool

 

Pull the pan & clean the screen. If you're lucky the valve body can be blown out and things return to normal.
You can probably rule out finding one there, but early production '56 Deluxe 88s were still dual range equipped - they even had their own owner's manual.

 

Pull the back end of the granny and clean the governor. Been there before...

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Does it change as the tranny warms up (fluid gets thinner?)


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Sounds like a spring broke probably in a clutch pack for it to happen w/o warning. Also if it is an old build, a hardened seal might have broken. Regardless an instantaneous failure probably needs a rebuild.

That is a strange tranny with its two fluid couplings.

 

Slim jim jetaway trans were junk, and still are. Get an adaptor or what ever and put a turbo 400,350
700r4, torqueflight,AOD, or anything before you spend money on that piece of shit. Ask me how I know, lol

 

http://www.forwhatyouneed.com/transmission adapters, conversion.htm

 

It's $300 or so for the rebuild kit. Most likely you have a blown seal. If you are thinking of a different transmission anyway, why not just buy the kit and and try to rebuild it yourself? If you mess it up you've lost $400 and you have gained knowledge and experience about rebuilding automatic transmissions. What have you got to lose, three or four hundred $$ ? If it's a failure look into doing a swap.

How much is an an adapter, either a new or rebuilt transmission ( because you can count on a used one needing a complete overhaul), all the bits and bobs, modifications and kick down levers etc. to make a different trans work ? Not to mention everything that could go wrong.

I'm no brain surgeon, in fact I barely have opposable thumbs and I live in a tree, but I gave rebuilding my own Hydramatic a go, and it worked out, $300 and some time, it was one of the most satisfying things I've ever done. Just keep everything in order, study your manual and take a lot of pics. No problem. The nice thing is that everything goes back and fits right.

Maybe someone who thinks your tranny is a pos will volunteer to fly to Germany and walk you through a swap. Hope they like sausages and beer. (I love sausages, but I like Budweiser)


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I had the Jet away rebuilt for my 98 coupe with a kit from Fatsco some years ago.
It actually drove really well after the rebuild.
I have 3 of them sitting on my garage floor, if you lived closer I would give you one.
Good luck with it.

 

The slim jim or roto hydro is not the same as the jetaway or dual coupling hydo. And, the jetaway was made from 1956 to 1964...fyi

 

OK, how do you know???

 

... I drove there ... and for 30 miles it worked all fine

 

First time posting. Been reading for a while and thought I could add to this topic.

My dad was an automatic transmission mechanic for many years and people used to wait to get him to fix their cars as he was known to be very good.

But I remember him showing me a trick with the jetaway in a Cadillac. There was a valve in the valve body that was known to stick and cause similar problems. (Especially when sitting for a while) He would take the car out for a drive about 20 mph coasting, engine idling then temporarily move the shifter to reverse. For only about one second, just when you felt the transmission start to shift to reverse you put it back to drive.

You don't want it to go into reverse, just start to put oil pressure to the valve from the other direction which would jar the valve loose.

In this case, we drove it a while longer to make sure everything was good and gave it back to the customer.

I don't know if you want to try anything like that. But there is probably nothing seriously wrong that a cleaning of the valve body wouldn't solve.


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I'm telling you from experience when they get stuck in first and won't shift it's the governor. Pull and clean it first. It doesn't cost anything to do first.

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Dog walkin got me thinking. Maybe it was the governor that was sticking. And not the valve body. After all it is a valve as well.


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Poncho60 beat me to the draw, but I agree. I'm almost 80 and was around and car crazy then as well as now. When the '56 Olds came out with the infamous Jetaway, everybody from HRM down pronounced it as a definite downgrade when it came to performance, and after a couple of years it became well known as almost impossible to repair/rebuild. Poncho says last year'64, and I suspect that's correct. Then came another POS, the "Slim Jim", which is why I always avoided those years also, unless it was a manual trans.
I realize JohnnyOlds98, that being in Germany makes things even more expensive, and your being short on funds just now doesn't help. Today's knowledge is advanced from then, and far more obtainable thru the web, but still, you have to consider carefully on what to do.
If it were me, I'd drain, remove pan and clean screen(s) and change filter, follow Dog walking's suggestion of removing the governor, cleaning it thoroughly and replace. Fill with name brand fresh fluid, then try it out. Might just work. Good luck and keep us informed.

 

X3^^^^^^^^^^^^

Also, drop the entire valve body (easy), disassemble it, clean it and make sure everything is moving freely. (Make sure you put it back EXACTLY like it was). This is another possible fix without removing tranny.
Good luck!


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Pretty sure the POS roto hydro (slim Jim) didn't come out till 1961, and was done at the end of the 1964 model year. The only auto trannies in Olds / Pontiac in the 50's were either the dual range or dual coupling hydros. No slim Jims as stock trannies in those years unless someone was stupid enough (IMO) to put one in at some later date.

 

Many thanks for your feedback. Will try cleaning the valvebody first - if there are any hints in doing so by checking the oil for signs of excessing wear or in case gaskets and seals don't look good anymore I will consider a complete overhaul ...
Will keep you posted!

 

If you have the valve body out there may be some air checks you can do to see if the internal seals are leaking or you could hear a clutch pack that has to much travel that would be a sign of a burnt clutch pack.

 

All those quick checks do for sure but I am afraid when a tranny crashes all of a sudden. In my experience it has been something like a servo spring or clutch spring that broke or a hard rubber seal that has broken and blown out.

My folks had a seafoam green and white 98 back in the day. Was our first car with A/C. Really a beautiful car. They traded it in on a light metallic blue '63 SS Impala 2dr HT with all the engine turned panels and 327. That was the car I learned to drive in and took my wife to the prom on our first date in HS.

 

I hate to sound like a broken record but if you have a jetaway that has been shifting fine. Then suddenly without any noises or strange things happening but suddenly won't shift out of first you need to pull the governor and clean it out. When you do it won't really look dirty. Just take apart what you can on it and spray it out with carb cleaner. Be sure it moves freely and put it back together. It most likely will fix it. Its about a 30 min. Job and it saves you from pulling the pan and valve body.

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Dogwalkins advice is sound. If it was a catastrophic failure of a seal or spring, it would effect only the gear it is associated with. And it would shift out of first and into the effected gear which would not be there so it would spin out (basically neutral). (Unless it resulted in severe leakage like the pressure regulator valve. In which case it would probably slip in first) Stuck in first has to be a valve not moving. The governor is the most likely and easy to check. My dad always told me the valves have to move thru the bores under their own weight. (Would apply to the governor too). Even the slightest burr, spec of foreign material will prevent that motion. He used to wet sand with solvent and 600 grit paper on the valves to eliminate the burrs. Sand lightly around the circumference not axially. You don't want the sand scratches to create a leakage groove directly across the valve.

Only sand if the valve won't move under its own weight. Wash and blow dry with compressed air. 600 wet is pretty fine so it won't remove much metal. But go lightly.


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the hydramatic came stock on 88s in 1956; 98s got the jetaway.