The Stovebolt Site Forums The Shop Area Driveline 55S1 Hydramatic

I found a truck parked for a very long time (20+ years?) with the motor and trans in the back. Pretty rough. I would expect it to be a core trans/bell/etc. What am I looking at investment wise to rebuild this trans and what parts do I need to make sure I keep if I were to go for it?

Dan,

Have you ever been inside an automatic transmission (and rebuilt it)?

Do you have access to tools to work on a Hydra-Matic transmission?

Having someone (who knows what they are doing - who has done this successfully) rebuild a Hydra-Matic transmission is quite expensive (upwards of $3000 plus shipping). Gene at Restoration Hydramatics knows what he is doing.

Northwest Transmission Parts says that they sell parts and rebuild kits.
TransPartsOnLine says that they sell parts and rebuild kits.
Autotran says that they sell parts and rebuild kits.

If someone who has rebuilt a Hydra-=Matic reads this, maybe they will post their experience (and words of advice/wisdom).

I have two 1954 1/2 ton Chevrolet truck Hydra-Matic transmissions. I know one works and I know nothing about the other one, except that it is part of a complete drive train I bought about 14 years ago. I found the engine to be useless - a full length crack near the base of the block.

When I get the truck with the good Hydra-Matic running again, if the Hydra-Matic goes bad, I'll find a way to get Gene Berck to rebuild it (the link is given above).

Try to keep the engine and trans together, if possible. If all the bits and pieces are saved, such as flywheel, bellhousing, starter, etc., the transmission will bolt onto any stovebolt engine, but the original engine block will add to the value and collectability if it can be saved.

Hydra-Matics are not easy to build, and a few special tools are absolutely necessary. There is a servo assembly with a BIG spring in it that will launch itself into the middle of next week unless it's restrained and released slowly and carefuly with a special fixture. Another parts source is FATSCO transmission parts in New Jersey. They have good information about the various different models of Hydramatics, and there are many variations of them over close to 20 years of production. Find a pro to build it!
Jerry

Jerry,

Do you know anyone on the east coast that rebuilds Hydra-Matics?

Thanks,

My father is the only one I'd trust to work on one, but he's 86, and doesn't do much more than offer advice when I'm into a transmission job. He fed me and three siblings all through the 1950's by fixing those things, probably a few thousand of them! He was the first or second man in Nashville to work on automatic transmissions, starting in about 1946 or 47. My experience on the original Hydramatics is pretty limited, but I've done a few in my time.

These guys are probably pretty close to you, and they could probably reccomend a good builder in the area. I've done some buisness with them, and other than talking funny, they're pretty good guys to deal with!

http://www.fatsco.com/index.htm

Jerry

Thanks guys. I wouldn't attempt it myself but wanted a clue as to how much it would cost. The truck is pretty much a parts truck and I can't guarantee the whole pile in the bed is complete. I see the block with the integrated bell half parts, the torroid/converter, and the trans. I'd hate to see it all go to scrap but I'm also not looking for a full resto job for my truck either so my budget is not in the thousands for a trans!

If you decide not to go for a rebuild, drop me a PM before you scrap it. I've been collecting oddball parts for some time, and I'd be interested in adding a Hydra-Matic to the list of "one of these days" projects.
Jerry

Dan,

If you decide to sell the H-M transmission, rear-end, and other mounting parts (and/or part out the transmission), post Parts For Sale ads in the Swap Meet. There are people with Hydra-Matic transmissions who are always looking for spare parts.

I will probably p/m and post it up. Not sure of the value but I do know I'm not up for a $3000 rebuild!

If anyone is looking for a hydramatic, I have one in the parts for sale section now. Just do a search for HYDRAMATIC.
Thanks.

Parts to try and keep together would be the transmission, the adapter plate. the starter along with neutral start switch and shift detent mechanism that clamps onto the steering column under the hood, all, shift linkage, the linkage pivot on the side of the engine block, driveshaft and torque tube (different length) crossmembers as they are designed to bolt in instead of rivet to frame.(they are also much heavier),some say the brake master cylinder is different but it looks the same to me with the exception of different brake line routing for the drop out crossmembers, the transmission cover is different as it "climbs the firewall to allow access to the bellhousing bolts), and even the cab is different for the recessed area and strengthening ribs fot the trans cover. Obviously, the shift mechanism is different also. Other than that, GMC and Chevy used different linkages and shift mechanisms even during the same years. Did I miss anything?

Yikes. Sounds pretty much like the whole truck. Floor cover is gone. Shifter is still on the column but after that, who knows!

Is this a GMC or a Chevrolet? It does make a difference. Chevrolet Hydramatics are a little harder to find and worth pulling them out before sending the truck to the crusher. Save the rear end too, it should have the open driveshaft and 3:90 gears. The rear end will fit in all 47/55 trucks and allow you to have a different transmission and chuck the torque tube.

rear springs too as these are ideal to mount an open driveshaft rear end in an AD truck. The centering pins are in a different location than the leaf springs from an earlier truck and later years used a wider leaf spring.

Saw you had a hydramatic for sale, I'm in need of linkages brackets.

Thanks,
Andy

I have a 54 Chevy with a Hydra-matic but the ID plate says CHT-55-XXXX so I suspect this means 1955? Anyway, I had to remove the torus for cleaning. The torus cover has 6 springs (look like valve springs) and one is cracked. I also noticed a hairline crack near a rivet on the other torus half. I called Gene and he said this is common. He replaces these parts that are common to fail after many years of shifting gears. For a 5 year warranty, it's a must. I got the impression that this is not something you would normally get in an overhaul kit so this probably helps explain the cost of Gene's rebuilds. I also noticed my bell housing casting said GMC instead of GM. Gene said he believes this was original to the truck. He talked with me for at least an hour. He said most of his Hydra-matic rebuilds go to Cadillacs and lately Packards. The 1954 and 1955.1 Chevrolet truck Hydra-matics are rare.