The Stovebolt Site Forums The Shop Area General Truck Talk 1954 Hydramatic truck: use engine for manual tranny ?

Is it possible to use a 1954 Hydramatic engine with the regular bell-housing and manual tranny ?

Or, are there specific features of the Hydramatic block/ crank that would prevent this ?

Here's part of the story... I just purchased the leavings of somebody else's rod project , which involved a '54 Chevy 3/4 ton Deluxe Cab pick-up: Hydramatic, five-window cab, chrome grille, stainless trim around the windshield, two-tone paint, etc: the full-blown top of the line '54...

I was lucky enough to get to the engine and complete chassis before they got cut/junked.
(The damage was already done :mad: ... I'm trying to salvage what pieces I can...

Supposedly, the engine was rebuilt in 2000, and has less than 10,000 miles on it.

I bought this outfit primarily as a parts donor for my '54 3/4ton truck, which is a five-window stripper, w/ 3-speed stick.

I am wondering if the engine can be set-up to work with the manual tranny, and also whether the frames were different for trucks using the Hydramatic.

Would appreciate any help...

Thanks...

The Hydramatic engine can be used with a manual tranny as long as you find a flywheel and bellhousing to fit. You will need to check to see if the crankshaft has been drilled for a pilot bearing. If not you can either have a machine shop drill one or swap out the crankshaft. I've heard that some were and some weren't.

However, the converse is not necessarily true. Hydromatics were matched to the engines. To get a hydromatic to work properly it has to be precisely machined to fit the block, therefore they are a matched set. If you still have the transmission you may be able to sell the set to someone who needs it and have enough money left over to get a nice running 261.

I know the cab floor cover is differant for the hydromatic, and there should be no hole for the clutch pedal. Don't know about the frame, but the engine will be fine.

"To get a hydromatic to work properly it has to be precisely machined to fit the block, therefore they are a matched set."


I guess that explains this message cast into the top of the Hydro bell-housing:

"This bell housing must be used with this engine"

Once we get the chassis dragged-home, I will see about getting the engine running, and got from there...

I believe that the writing on the bellhousing actually says that the plate between the trans and engine are matched. I personally put my hydra-matic trans behind an engine that was originally 3 speed. I know of others that did the same thing. They checked the runout and all was within spec. I just chanced it and all was fine. I bought a rolling chassis and the previous owner had installed another engine already so I felt that I was in the same shape using my existing known good condition engine. The question of using manual trans bellhousing will not work. There is what I call for lack of a better description, an adapter plate between the engine block and the trans bellhousing. The flywheel is different as the torrus cover bolts up to it with a big seal to make basically a torque converter. The hydra-matic truck has a different frame in that the trans crossmembers are much bigger and designed to unbolt so that trans can be removed from the bottom side of truck. Brake line routing is different for the same reason. The cab floor that was mentioned is different to accept a different trans cover that gives access to the bellhousing bolts and also gives access to the trans dipstick. The driveshaft is a different length and the Hydra-Matic has a solenoid starter instead of the foot starter. It also had an auto choke carb with heat from an exhaust manifold stove plate. If you have the trans and misc items and want to go with a different driveline, I can give you an e-mail address of someone that wants the Hydra items. If going the other direction, I think I can give you a number for someone that has 3/4 ton truck that was originally hydra-matic but I do not remember if it still had trans or not. I also am not certain whether or not the 3/4 ton had an open driveshaft or just an extension on the original driveshaft. Tell us more about the project intentions.

"To get a hydromatic to work properly it has to be precisely machined to fit the block, therefore they are a matched set."

Just out of question, what sorts of problems occur when the engine isn't machined to the hydramatic transmission?

Well,

Chrysler Corp automatics through 1962 have kind of the same issue; if the centerline through the shaft crankshaft & input shaft of the engine and tranny aren't in perfect alignment, it could cause a variety of issues, from vibration to trashing of seals, pumps, torque convertors...

This is one of the reasons auto/truck makers went to a flex-plate to couple the torque-converter to the crankshaft...

A few thousandths of a inch "misalignment" between the engine and bel-housing/tranny could mean big problems...

I have been reading my '54 SHop Manual, and it give a detailed proceedure for checking the centering/alignment/ run-out between the bell housing and crankshaft for the Hydramatic, and also for the regular bell-housing for manual tranny trucks... plus a proceedure to correct unsuitable alignment...

I didn't know though if there were different dowel-pins ( size, number, location) to locate that Hydro adapter...

We're supposed to bring the chassis home tomorrow ( in the torrential remnants of Ernesto)...

Thanks...

The hydra-matic trans input shaft is actually supported by a pilot bearind or bushing in the back of the crankshaft. There is no balance issue that I know of on the flywheel. As mentioned, there is a runout check on the flywheel face which would apply to any flywheel. Then there is the runout check of the opening to make sure that trans input shaft is centered with the crankshaft. That is the one that would be corrected with offset dowel pins if needed. Think of it this way, In 1954 if a block froze and cracked, the dealer would not have scrapped the whole driveline. They would have replaced the shortblock, checked the runouts and corrected with the offset dowel pins if needed and sent it on it's merry way. I expect that the dowel pins would be a job for a machine shop now if needed. I doubt that they are still a stocked item at the parts counter.

Back to your original question. Yes. A beter idea would be to sell the engine to me.

Well, the '54 3/4-ton Hydro chassis & running gear made their way to a "safe place" on Saturday... lots of fun winching a chassis onto a trailer in the steady drizzle, then trying to claw our way up a steep, greasy clay driveway...

Will dig into it a bit this week and see what kind of shape the supposedly-rebuilt engine is in...

The Chevy linkage is different from GMC. Don't let any of the special parts get away thinking you can replace them later.