Posted By: Doc.Hall 54'-3100 hydromatic - Sat Jun 13 2020 05:58 PM
Thinking of a good used one or prefer to rebuild one. Doc
Posted By: tclederman Re: 54'-3100 hydromatic - Sat Jun 13 2020 06:46 PM
"54'-3100 hydromatic"

You are probably referring to a 4-speed GM truck Hydra-Matic transmission?

Here are some hydromatic transmissions/etc []?

You say you want to rebuild one?

Have you ever rebuilt one?
They are complicated (compared to a manual transmission).

Do you have the special tools that are needed?
They might show up infrequently on eBay.

These ten pages of photos might be of interest? []
Posted By: Doc.Hall Re: 54'-3100 hydromatic - Mon Jun 15 2020 03:23 PM
tclederman, yes I have but only the old Oldsmobile hydromatic. We would put them in Tri-Fives street and strip racer's with the famous Hydro-kit. AAAAH those were the days. One was my favorite a 57 with the 283 150 body (taxi cab body), no back seat from factory with Zakes Duntov factory modification's. Punched to 292 cid. Nine thousand many times. Oops, I'm getting melancholy. Any way I still have all my tools safely stored just like new. tc is the Chevy very different? Ed
Posted By: tclederman Re: 54'-3100 hydromatic - Mon Jun 15 2020 03:26 PM
Excellent, Ed

I have no idea how different those transmissions might be.

I know almost nothing about the Hydras and I know nothing about the Hydros.
Posted By: Doc.Hall Re: 54'-3100 hydromatic - Mon Jun 15 2020 03:46 PM
tc, Was the hydro and hydra a GM name for different makes? By the way you are a library of information. Ed
Posted By: tclederman Re: 54'-3100 hydromatic - Mon Jun 15 2020 04:37 PM

I know nothing about a hydromatic/hydro-matic transmission (GM or others).

Maybe someone will post information on a hydromatic?

There is a GM Turbo-Hydramatic or GM Turbo Hydra-Matic transmission (and, a GM Roto HydraMatic).
Posted By: Hotrod Lincoln Re: 54'-3100 hydromatic - Mon Jun 22 2020 04:05 PM
The first transmission of any kind that I worked on was a Dual Range Hydra-Matic in 1958. (I was 12 years old) My father was the first man in Nashville Tennessee to rebuild automatic transmissions, beginning in the late 1940's, and by the late 50's he was teaching transmission repair courses for General Motors, after hours in the family shop. I sat in on the classes, worked alongside the mechanics who were training, and passed the end-of-course test. GM sent me a certificate stating that I was a "factory-trained Hydra-Matic technician"!

No matter what vehicle the transmissions happened to be installed in, the internal workings were practically identical. Olds, Pontiac, Cadillac, GMC and Chevy trucks, Nash, and a few other car lines all used that transmission- - - -even Rolls-Royce and Lincoln Continental used the H-M at various times. Thousands of WW II 6X6 trucks and the Stuart light tank also used an earlier version of the H-M before the Dual Range shift pattern came out in the mid-1950's. The Stuart used two Cadillac flathead V8 engines and two transmissions.

The original Hydramatic came out in 1938 in Oldsmobiles and some Buicks- - - -with a manual clutch. It would shift automatically, but the clutch had to be disengaged at a stop. By 1940, a fluid coupling was added to let the engine idle in gear.
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