Hydramatic Transmission



Roto-Hydramatic 375

Also known as Model 10 or Slim Jim.

Used 1961-64 in some Buick, Olds and Pontiac models.

There is some disagreement as to this being a 3 or 4 speed transmission. It only shifted twice, so many people consider it a 3 speed, but it had an internal torus torque multiplier (similar in principle AND operation to today's torque converters) that did give it an initial additional 'ratio'.

Do not confuse with 375 THM used later that was an adaptation of the 400 THM, but with a 350 THM size output shaft spline or the version of the 350 THM that GM called a 375 THM.

This was an hydraulically controlled transmission.

TV rod adjustment

Disconnect rod, push (and hold) the gas pedal to the floor, push the TV rod (and hold it) until it bottoms in the valve body, adjust the length of the rod until it will just assemble back together.

Gear Ratios:
starts out at 3.50:1 and becomes 2.93:1 when 'torus becomes hydraulically coupled' 1st gear
1.56:1 2nd gear
1.00:1 3rd gear
2.42:1 reverse


Transmission

Pan and Gasket

(click on picture to enlarge)

Copyright© 2003, 2004, 2005, 2011, 2013, 2015, 2020 Charlie Tranny

When Your Classic Car Needs a Rebuilt Automatic Transmission

Hydramatic (Standard and Dual Range) Also known as Single and Dual Path. The Dual Range was introduced for the 1952 model year. NOTE: This was the 'original' Hydramatic, but GM called MANY of their later transmissions 'Hydramatic'. Pontiac calls the dual coupling Hydramatic Strato flight, later Super Hydramatic, Cadillac calls it 315 Hydramatic, Oldsmobile calls it Jetaway, and Detroit Transmission who designed and built it call it P 315 Controlled Coupling hydramatic. Edited February 24, 2012 by helfen (see edit history).


What do you do when your classic car transmission stops working?


Hydramatic Transmission

Relax and let the experts handle your transmission problems at Transmissions by Gene. With more than 40 years of experience, Gene Berck, an early transmission specialist, has the equipment and the know-how to repair any transmission for older vehicles from the 40's, 50's and 60's. He takes pride in his work, guaranteeing that his customers will be 100% satisfied with his services. Ship your transmission to him and he will overhaul it and send it back within a 10 to 14 business day turn around time. Stop in or contact him for more information on his excellent transmission services.

Hydramatic Transmission History


Transmissions by Gene has been doing automatic transmission repair on all types of transmissionsfor 42 years nationwide. Cast iron Hydramatic, Jetaway AKA Stratoflight, and Powerglide are some of our common monthly units. We also offer transmission soft and hard parts for all transmission 1941 to present. Units can be removed and shipped to our Salinas, California, transmission shop. We will rebuild your unit and ship it back to you in a reasonable time. Classic car automatic transmission overhauling is a very technical trade. Let us rebuild your unit rather than swapping to a used unit that won't work or won't work very long. We are available 24 hours a day, 7 days a week. Our Salinas, California, transmission shop is open 9 hours a day, 6 days a week. We can build conversion units as well, for upgrading or better choice or availability. Contact us for all of your early automatic transmission needs


Not many people understand these early transmissions. But that's not the only challenge. There is more to these transmissions thanknowing how to build them. The parts have not been available for 30 years. They weigh 250 lbs, so we have built special fixtures todisassemble, assemble, and clean them. All units are band adjusted and ready to install. Mount the transmission, and after all is checked andtight, add transmisison fluid slowly as directed.


When You Need a New Transmission

You just bought the classic car of your dreams, but it's missing a few things. Including a transmission. Or something happened and the transmissionyou have just isn't rebuildable. We can help!. We know what you need and what's out there. We can usually findyou the right model and year for your car, and rebuild it like new. If not, we can provide a different model but the right year, rebuilt to work perfectly untilthe right model becomes available. Call us!


Hydramatic Transmissions

You've got a Muscle Car?

The Muscle cars from the sixties through seventies had special transmission needs. From the factory they were offered withspecial modified transmissions that could stand the higher RPM's and torque. We know how to rebuild them to perform not just like the factorytransmissions, but with the extra strength you need. What if your engine is hotter-than-stock? Don't take it tojust anyone- you really need to call us. We can rebuild your transmission to handle the extra power,and you can't match our price and quality.


Parts & Manuals

You said you want to do it yourself? Are the parts and manuals available locally? Probably not,but we can help. We have sources and can get manuals and parts for most classic transmissions.Save a bundle on shipping, and have the satisfaction of knowing you've fixed it yourself!

Trust our transmission overhaul expert for allyour classic transmission overhaul needs, nationwide and internationally.

We also have a good selection of factory service manuals and othertransmission literature from the 30's through the sixties. This includesmany hydraulic circuit diagrams in color and trouble shooting sections.We can make this available to repair shops. These are written for thetrained transmission technician and will not be useful for the classiccar owner. Contact us if you are a transmission shop and need thisinformation.


MERCURY:
MERC-O-MATIC 2&3 SPEED
MULTI-DRIVE
CORVAIR:
POWERGLIDE
CHEVROLET:
IRON POWERGLIDE
ALUMIMUM POWERGLIDE
TURBOGLIDE
4SPEED HYDRAMATIC
TORQUE DRIVE
PONTIAC:
SINGLE & DUAL RANGE HYDRAMATIC
ROTO 10 'SLIM JIM'
JETAWAY 4 SPEED
AKA STRATOFLIGHT
HYDRAMATIC
'TEMPEST TORQUE'

Hydramatic Transmission Rebuild

CADILLAC, OLDSMOBILE:
HYDRAMATIC SINGLE & DUAL RANGE
JETAWAY
FRONT WHEEL DRIVE TURBO HYDRAMATIC 425
ROTO 10 'SLIM JIM'
F-85 ROTO 5
BUICK:
FLIGHT PITCH *
TRIPLE TURBINE
TWIN TURBINE
DYNAFLOW
CORVETTE:
'53-'55 SIX CYLINDER CAST IRON POWERGLIDE
'55 -'61 V8 CAST IRON POWERGLIDE
'62 -'67 ALUMINUM POWERGLIDE
'68 -'81 TURBO HYDRAMATIC 400
'82 -'92 700-R4 OVERDRIVE AUTOMATIC'84 -'88 BORG WARNER/DOUG NASH '4+3'
'93 AND LATER 4L60-E ELECTRONIC OVERDRIVE
CHRYSLER, PLYMOUTH, DODGE:
POWERFLITE
TORQUEFLITE : CAST IRON & ALUMINUM
JEEP:
TURBO HYDRAMATIC (GM)
TORQUEFLIGHT (CHRYSLER)

Hydramatic Transmission Parts

STUDEBAKER:
BORG WARNER
FLIGHTOMATIC
PACKARD:
ULTRAMATIC DRIVE

* A Buick Dynaflow conversion is recommended because FlightPitch parts are not available.

Hydramatic Transmission

Our prices are reasonable. We start working on your transmission promptly when we get it.And we'll get it back to you running like new.

Feel free to call and ask for me. We can help, and we look forward to working for you!