Projects 56 Cadillac manual transmission swap

I recently purchased a 1956 Cadillac sedan deville and have been having problems with the hydromatic transmission, when it starts its fine but after driving a little if you try to put it in reverse it makes horrible banging sounds if you feather the throttle it will go in gear but I'm worried I'm going to end up destroying the transmission. I've asked around and the general consensus is that I'm going to have to rebuild it. I've been trying to turn the car into a mild rod new cam intake stuff like that. would I be better of replacing the transmission with a munchie? as there are adapters available and how feasible is it as I've only seen Cadillac 365s with manual transmissions in early fords.

 

As much as I love a manual trans I can't see putting one in a caddy. Can you adapt to a better newer automatic?

 

Yeah I just want a manual transmission but it might be a little strange with the bench seat.

 

It CAN be done....but I really doubt you have a good grasp of what is involved,
in time, money and effort. And, even if you devoted all those resources to it, what
benefit would you have gained, considering the type of car it is.

As Scotty T suggested above, swapping in a newer automatic is by far the better option.
Both Wilcap and Bendtsen's (transmissionadapters.com) have adapters for all the common GM automatics.

Ray

 

I agree that the current trans is a loser, GM changed from the "dual range hydramatic" to a "jetaway hydramatic in '56 and it was a piece of junk then and hasn't been considered worth a rebuild in a long time.
Please, don't fuck up a beautiful classic by cobbling up a manual trans in that Caddy. Do some research here and elsewhere on the web for a way to change to a better automatic like a turbo 350 or 400. If you do it right,you'll have a great car.

 

Just out of curiosity - what was the last year that Cadillac offered a standard trans?

 

Maybe 1950-ambulance and hearse package.

 

Just did a search and found somebody selling a Cadillac factory stick package last autumn from a 1954 limo. Was surprised Cad had stick that late.

 

Just Old Timers opinion, keep it an automatic transmission car for if no other reason, for resale, again IMO do not think a shifter mid 50's Caddy would be an easy sell, BUT, this whole car deal is about individual thinking and your vision of your deal. Hopefully someone on here will give you some tips on what will bolt up to your engine and search internet for Caddy groups/clubs, somewhere somebody has these answers. Good Luck !

 

It would be less work to switch to a later style automatic.That being said if I were doing it I would hunt for a caddy stick bellhousing and flywheel-look at sources like Hemmings motor news_ and likely use a Muncie or BW T-10 4 speed just because they are available.You could also use a 3 speed all synchro from a 70s-80s GM fullsize pickup if you have one of those laying around. Good luck.

 

The flywheel, bellhousing, trans etc. is really the easier part, in my opinion. Just takes money and some research to find the parts. Setting up a suitable and reliable clutch pedal and linkage, even hydraulic, seems to me to be the more challenging aspect of such a conversion.

The greatest danger of all, is that you ignore the advice offered here by experienced people, embark on the stick shift conversion......and then find out what you are up against and abandon the project altogether. A nice old Caddy is rendered nearly valueless and you have wasted considerable resources by that point. It doesn't have to end like that, but the countryside is littered with aborted projects of all kinds and that suggests what the odds are as to the outcome.

Whatever you decide, best wishes.

Ray

 

Why not buy a kit from Fatsco for $300, drop the tranny and try to rebuild it yourself? If by some freak occurrence it works, you can drive around in your Caddy collecting parts in the trunk to do a stick conversion later. If you botch it up, you've lost $300, but will have learned exactly how an automatic transmission works and how to rebuild one, like going to auto restoration school, some chumps pony up big dollars for that privilege.

Even adapting a later trans is not just bolting it in. If life was that easy, we would all be drinking mai tais by a pool somewhere.

 

Want a manual trans car? Buy a different car that actually came with a stick.

 

This is the perfect comment on a hot rod and custom site!

 

Some cars were not meant to have manual transmissions. Your Cadillac is one of them. Rebuild the original transmission or swap in a newer automatic. Don't fuck it up by trying to put a stick in it.

 

You have a valuble, and desireable car now, if you put a stick in it you will lose that. Cadillacs are great customs, not hotrods, maybe sell the Cadillac and buy something more suited to being a hot rod?

 

Wilcap sells adapter to make the rear of the engine think it's a Chevrolet.. Rest is just fabrication... Good luck.

 

Don't screw that bitchin' ol' Caddy up. That thing is a valuable original classic. Get in touch with an old Hydramatic trans guy like Art Carr or ? who has been around since that car was new and see what they recommend.

 

The '55 Caddy still had the dual range hydramatic IIRC, and that's the best hydramatic that GM built. If you could find one of those cars thjat was all there mechanically, but a wreck or rust bucket otherwise to use for a donor, you could rebuild that dual range and install it along with the bits and pieces that are different between the 2 cars underneath.
But unless you find somebody that will lie to you about fixing that jetaway so they can rip you off for a "rebuild" that won't last, any good trans guy is gonna tell you that trans is not worth rebuilding.
That or follow post #17 suggestion from Jimmy Six.
You have a beautiful classic, don't fuck it up.

 

I stumbled onto these Hydro rebuilders and since I don't know where you are can't recommend anyone in your area.
http://www.restorationhydramatics.com/
http://www.vintagetransmissionrebuilding.com/
http://www.autotran.us/
I personally wouldn't swap to a stick although being novel. IMHO some things are best left alone like nature originally intended.

 

Wish Bruce Jenner felt that way. Eating Wheaties 'aint the same.

www.autotrans.us just sells parts and rebuild kits like Fatsco. A master rebuild kit will be around $300. More complicated than an engine rebuild, but parts cost way less.

Rebuilding a Hydramatic isn't brain surgery, here's a guy who posts a couple of hours of video walking us step by step through the rebuild of a '55 Olds Hydramatic:




This article helped me a lot with a 1960 Hydramatic, but still has some good info:

http://www.photopaige.com/edscars/60caddy/CaddyWebSitev2_files/TrannyRebuild2.htm

This site's about building things, figuring out how to fix stuff and getting your hands dirty, right?

 

'55 is dual range and '56 jetaway IIRC, big difference.

 

I think the last year was 52 or 53 but I might be wrong, either way they didn't make many overhead valve caddys with manual transmissions

 

I think you're right. '51 last year for standard series, '53 it was an option for 75 series only, in '54 wasn't even an option at all, until 1982, but you had to have a red leather jacket with lots of zippers and be able to moonwalk for the dealership to sell you one. From other websites Post war manual transmissions on Caddies were really rare.

 

I'm a little late to the party here, but maybe this will help out someone reading this thread in the future.

So I'm planning a build myself I would like to find a 50 or 51 Cadillac coupe. Drop a 454 with a manual trans in it. And paint it up like Briggs Cunningham's in a 24 hour of le mans tribute

Since all I can find are automatic trans cars, and the pedals are extremely rare I will have to improvise

I am really familiar with the 49 to 52 chevy stylelines. Which parts are readily available and reproduced. Not to mention fairly similar to these years of caddys.

There is a bracket for the 49 to 52 chevys that bolts to the frame rail and allows a modern dual resivior master cylinder (still standard brakes) and keeps the original pivot point for your clutch linkage (factory on the chevys, it would of been right on the old single res. Master) and allows you to keep your original pedals

Now, this will not be 100% correct locations on the caddy floor board, but it will be very close. Without having one in front of me I do not know exact measurements. You may have to shim or custom fab this chevy bracket onto the caddy frame rail. You will have to drill new holes for the pedals and for the shifter its self in the center hump. If your lucky there will be a removable panel on top of the trans tunnel like the chevy autos had in the 49 to 52s buuuut I doubt it.

This conversation in my opinion would be the easiest, cheapest, and take a lot less fab work/ engineering. Keep in mind that you will still have to custom make the linkage from the pivot point to the clutch fork, but that should be very straight forward.

Any thoughts on this?

 

Also, I never plan on selling any of my builds. They are just for me, and built the way I like. It maybe a rare site to see an old caddy with a generous rake, big fat rear tires, loud pipes, and a 4 speed trans... but hey it would be the FANCYist hot rod in town

 

67..............I like the way you think!! I mean. you gonna cam it up and put a big carb and trick intake why not slip a 4 speed in it?!
Most folks will look and say......."wow. never knew Caddy had a 4 speed!!!" What a hoot!
IF you had the $$$ go with a Lenco!!
Be sure and put a 'gear' in the back....maybe narrow the rear and hang some "big 'unz"(think Mickeys) on the back. Its yours do what you want to.
(A lot of HAMBerz use to say that!!!!)
If you put a Hemi in it I bet you would win most of 'em bck over! Maybe a 671 blower sticking outta da hood will win the rest of 'em back?!!
Lottsa pictures is all I ask!!!
6sally6

 

Lol mickey's for sure! Il try and find a link. Hot rod mag has a budget build sheet for a 496 stroker putting out 700 plus change hp.. for $6500!! If it even got close I'd be what they call "a happy camper" .....should scoot that caddy along

 

are you f'ing kidding me! cars are f.u. on here on a regular basis! where are the "it takes a real man to cut one up" guys! i like stock too, but geez!

 

I would have a simple plate adapter made to adapt a 700R4 overdrive in it and enjoy driving it.