HydraMatic tranny help

[martyspaulding]

Hello all.

 

I'm restoring a 1955 Chevrolet, Suburban chassis, short bus. (Second series) It was built with a manual transmission, and has the original straight 6 engine. I want to upgrade the transmission to an automatic. I know that this model and year did have the HydraMatic transmission available as an option .... but WHICH HydraMatic ?

Does anyone out there have reference materials that can tell me which version I should be looking for if I'm after a stock setup ?

And what's a good place to find one ? I'd even buy a whole vehicle and part it out if necessary.

Edited March 20, 2022 by martyspaulding (see edit history)

[61polara]

It's the Dual Range HydraMatic.  See the link below for additional infomation.

Hydra-matic Transmission - The Stovebolt Forums

 

[F&J]

30 minutes ago, martyspaulding said:

if I'm after a stock setup ?

And what's a good place to find one ? I'd even buy a whole vehicle and part it out if necessary.

The transmission is just the start of all of the rare parts needed for a conversion.  You may never find everything needed without buying a complete parts truck.  

 

The truck hydro needs a hydro-only starter, and it must be the 6 cylinder chevy hydro starter, not the 8 cyl hydro starter. The trans/bell housing "adapter" that fits to the engine must be for a chevy 6 hydro, the 8 adapter won't fit. The "flywheel" is actually the front cover of a hydro "torus coupling" (that "looks" like a torque convertor), it must also be from a chevy 6 truck hydro, not 8.  The steering column parts like outer tube, linkages, shifter, and shift indicator must be from a hydro truck.  There are many more pieces exclusive to hydro truck, such as correct driveshaft and trans yoke.

 

Also another donor parts truck are the small stepvans like the US Postal Service used in the later half of 1950s. 

 

This will be a very expensive swap, not just the parts, but trying to find a shop willing/able to rebuild these 4 speed hydramatics.   

 

An easier route if you don't care about 100% original, is to use a open drive 2 speed Powerglide from a 55-up passenger car, and then modifying it's column parts/shifter to fit a truck column, and making a shift indicator.

[martyspaulding]

Thanks 61polara and F&J. This is *exactly* the kind of information that I have been looking for without much success.

 

It is good to know that rather than chasing a lot of parts (some of which may not fit) that I may as well just start the search for an entire donor truck.

 

Now on to THAT unicorn hunt ...

 

One other question. What year range can this be ? I'm guessing 1955 to 1962 ?  Or will earlier units fit ? This is the 4100/4102 flat face cowl line of truck. Not sure what a model conversion would have changed the specs on the drive train.

[rocketraider]

Curious if the truck HydraMatic was the slant pan Dual Range as used on Olds/Cadillac/Pontiac 52-55?

 

Info I've found states the truck HMT was basically the same unit 53-58, no Park position which leads me to believe it's the Dual Range unit. 56-64 Controlled Coupling units had dedicated Park.

 

Agreed. A lot of searching and work. The PowerGlide option sounds a little easier but no easier to find someone who can rebuild a cast iron PG than an early HMT.

[martyspaulding]

32 minutes ago, rocketraider said:

The PowerGlide option sounds a little easier but no easier to find someone who can rebuild a cast iron PG than an early HMT.

Assuming I can find the HMT, I really don't want to create even more work by needing to custom machine the linkage and such. It's a time v money thing. If I can find something that will fit, and find someone that can rebuild it. I don't want to reinvent the wheel on the installation difficulty.

 

Somewhere in some field or boneyard, there is one waiting for me. It's kinda like dating .... just gonna take a lot of bad blind dates.

[F&J]

32 minutes ago, rocketraider said:

Info I've found states the truck HMT was basically the same unit 53-58, no Park position which leads me to believe it's the Dual Range unit. 56-64 Controlled Coupling units had dedicated Park.

The above might be confusing to Marty when he is looking at the above 53-58 reference VS 56-64?  The "56"-up in "Oldsmobile Speak" refers to the New-for-56 Jetaway Hydramatic which I doubt was ever in a GM truck of any size?  1956 Olds retained the older slant pan 'hydro" in only the base cost 88, and the new Jetaway was used on all 1956 Super 88 and 98.

 

I have limited memory of just when was the last year of the old "hydro" in GM trucks.  They were uncommon for sure.  I want to say 59, only due to the 1960 body change?  Chevy/GMC Cameo pickups sometimes had these.

 

1 hour ago, martyspaulding said:

I'm guessing 1955 to 1962 ?  Or will earlier units fit ?

as I mentioned above, I don't know what is the last year for the "chevy parts truck" you'd need, but doubt it would be in a 60-62. As far as earlier than 55-1/2 body style?...  I thought the last couple of years on the older body style had open drive?  If so, maybe the ones with the hydro would work?  I am straining to recall if I ever saw a "chevy" older than 55-1/2 with the AT, but GMC definitely did.  Now, as the earlier cab was different, would the column shifter parts be the same?  IDK without a General Motors part book. 

19 minutes ago, martyspaulding said:

Somewhere in some field or boneyard, there is one waiting for me. It's kinda like dating .... just gonna take a lot of bad blind dates.

Yes, the more I think about needed parts, you must find a complete truck.  I forgot about the critical linkage system to the carburetor that controls trans fluid pressure increase as the gas pedal is depressed more. That would be tough to make correctly.

 

If you are somewhat near Kansas?, there are 3 different youtubers that buy a lot of farm trucks of that era.  They do sell parts or sell complete.

Here is a copy/paste from a recent post under the Junkyards section of AACA.  I am 99.9 sure this is one of those 3 guys as one of the other guys also says "Rust Ranch" in his videos, and shows his partner helping, as being "Joe". If you text Joe, ask if his friend Tim is the youtuber I am thinking of.  They both have many vehicles.   The 3rd Kansas guy is named Silas and is called "Adventures Made from Scratch" on youtube(who owns 3-4 junkyards in Kansas), Joe and Tim should have his contact info as Tim buys from Silas often.  These 3 guys are definite sellers! ...not ones who lead you along saying they "might" sell something.

 

"Posted February 17

I run a small salvage yard as a hobby/side-hustle. I have close to 300 vehicles. 99% are American iron, pre-1970. 
 

I save old cars and trucks from being crushed. I buy them at farm auctions, salvage cleanups, etc. 

 

Most vehicles are parts cars but I have many restoration candidates as well. I can ship most anything including overseas. You would need to set up your own transportation for complete vehicles or pickup beds. 

 

I can be reached at 316-300-7226 (texting is best, or leave a voice message). 
 

Email is rustranchkansas@gmail.com

 

Link to photos of my vehicles. 
 

Joe"

 

 

 

 

 

 

[F&J]

Here is Tim's contact info copied from his youtube account.  He is "Mr Goodpliers" on there:

 

"Have a question about any of the vehicles or parts at the Goodpliers yard, or the Rust Ranch? Send an email! mrgoodpliers1985@gmail.com

[martyspaulding]

44 minutes ago, F&J said:

Here is Tim's contact info copied from his youtube account.  He is "Mr Goodpliers" on there:

 

"Have a question about any of the vehicles or parts at the Goodpliers yard, or the Rust Ranch? Send an email! mrgoodpliers1985@gmail.com

If you were closer, I'd kiss you. 

 

[Dave39MD]

I am curious why you want to go through all the work and expense to convert the truck? Not saying you shouldn't do what you want with your truck but just wanted to know the reasoning.

 

Dave

[martyspaulding]

Just now, Dave39MD said:

I am curious why you want to go through all the work and expense to convert the truck? Not saying you shouldn't do what you want with your truck but just wanted to know the reasoning.

 

Dave

I lost my left ankle in a ladder accident some years ago. Manual transmissions are a real PITA for me to drive. 

[61polara]

If you are near South Carolina, I can recommend Greenville (SC) Transmission Service in Greenville.  They can rebuild a most any early automatic including PowerGlide and HydroMatic.  They just rebuilt a '54 Corvette PowerGlide for a friend, who was so pleased he took two more transmissions to them.

[martyspaulding]

50 minutes ago, 61polara said:

If you are near South Carolina, I can recommend Greenville (SC) Transmission Service in Greenville.  They can rebuild a most any early automatic including PowerGlide and HydroMatic.  They just rebuilt a '54 Corvette PowerGlide for a friend, who was so pleased he took two more transmissions to them.

I'm in Michigan. But if I'm lucky enough to find one, I won't mind to pay to have it shipped for a quality rebuild. There was a great tranny doctor near me, but he just retired and no amount of money is going to get him back into the grease

 

[Pfeil]

4 hours ago, rocketraider said:

Curious if the truck HydraMatic was the slant pan Dual Range as used on Olds/Cadillac/Pontiac 52-55?

 

Info I've found states the truck HMT was basically the same unit 53-58, no Park position which leads me to believe it's the Dual Range unit. 56-64 Controlled Coupling units had dedicated Park.

 

Agreed. A lot of searching and work. The PowerGlide option sounds a little easier but no easier to find someone who can rebuild a cast iron PG than an early HMT.

It's not a slant pan and it's not even the Cad-Pont-Olds dual range (1952-54). It's basically like the original HydraMatic with the 3.82 first gear but the difference being in the valve body. I'm sure many of you old time drag racers have heard of the old B&M hydro 4. Well, this G.M. truck HydraMatic has a shift quadrant like the B&M unit which goes like this N - 4-3-2-1-R. Reverse is like the Car HydraMatic meaning it's reverse gear and when the engine is off and the gear selector is in reverse because of no trans oil pressure it engages the parking pawl by a spring. So 1st gear is first 2nd is 1&2, 3rd is 1-2-3 and 4th goes through all the gears like 1-2-3-4. 

 

Please look it up page 142;

https://www.gmheritagecenter.com/docs/gm-heritage-archive/vehicle-information-kits/Chevrolet-Trucks

 

Edited March 21, 2022 by Pfeil (see edit history)

[Dave39MD]

I posted the question on the vintage Chevrolet site. Many of the same suggestions and one gentleman that did a similar swap.

 

Keep an eye on it maybe a parts truck will surface.

 

Dave

 

https://vccachat.org/ubbthreads.php/topics/468129.html#Post468129

[martyspaulding]

14 minutes ago, Dave39MD said:

I posted the question on the vintage Chevrolet site. Many of the same suggestions and one gentleman that did a similar swap.

 

Keep an eye on it maybe a parts truck will surface.

 

Dave

 

https://vccachat.org/ubbthreads.php/topics/468129.html#Post468129

Thanks Dave. I will follow that thread also. I'm not in a horrible hurry. I have time to find a rolling donor.