VCCA Home Forums TECHNICAL - GENERAL Trucks and Vans 1954 1-ton Hydramatic

I'm attempting to pull the motor from my '54 1-ton with factory hydramatic, and am beginning to suspect that the flywheel actually forms the front "lid" on the torque converter ... is this correct?

I thought I was removing the normal converter-to-flywheel attachment bolts, but then realized there were 'way too many of them!

My shop manual isn't real clear on engine removal (gee, whoda' thot to put that section in a shop manual?), but it's starting to look like I need to drain the oil from the pumpkin, then when all these bolts are removed the flywheel will separate from the back half of the pumpkin ... apparently there's a really big o-ring between the two.

On re-assembly, that will leave me with trying to keep a huge o-ring in place while I jostle the engine into position and align the flywheel back into place ... sounds like real fun!

Any help -- especially shortcuts! -- anyone can provide would be much appreciated.

You are correct. It you spin the torrus cover around, you will find a drain plug to drain trans fluid from that area. Then take all 18? bolts loose and it will seperate from the flywheel. There is a big O ring that sits in a groove of both halves. This should help click here

Thank you so much -- and especially for the links -- great stuff!

Now I see what has to be done, short of selling it the way it is (and this is sounding more tempting by the minute!)

Now I have another question -- Nowhere in any of the articles or in my shop manual does it talk about just "engine removal" ... do you know if the engine can (ie should) be removed without first dropping the tranny ... ??

In other words, is it necessary to install the tranny last in order to be able to align the o-ring, pins and bolts between the flywheel and the back half of the pumpkin?

Thanks again -- I appreciate the info.

I have a 54 3100 that was born a 3 speed. I bought a hydra-matic rolling chassis and proceeded to build it up with my engine and move the body over to it. I had the transmission bolted up in the frame and then installed the engine so the answer to your question is yes, you can pull and install the engine and leave the transmission in the truck. The differences in the frame and crossmembers between a manual transmission truck and a H-M truck is based around routing brake lines and being able to un-bolt crossmembers to remove the transmission from under the truck. The floor pan and trans tunnel is different for the same reasons to allow access to the transmission bolts. What problems are you having with your transmission?

Thanks Greg -- that's what I needed to hear !!

Actually no probs with the tranny -- it's just that the motor is blown so I'm trying to do an engine swap.

Given that there's a rod through the side of the block, I'm assuming it was being driven at the time, thus I'm fairly confident the tranny is good.

Looks like I'm into draining fluids, pulling a bunch more bolts and cracking the torus open!

Hopefully it all goes back together without too big a fight!

Thanks again -- everyone -- all info is much appreciated.

I had one of those hydramatic transmissions in my 35 chev when i bought it in 1970. It was a 4 speed auto and a 1955 olds version. First gear was 3.98 to one and really got the car going. The pumpkin as you call it is actually called a TORUS COVER. The system is called a FLUID COUPLING. That flywheel is very heavy.

I would have the motor outside the car and the transmission too. I think there is more than 18 ...7/16 fine bolts that hold the torus to the flywheel. My 55 olds trans had a one piece oil and gas proof paper gasket that only went on one way !! Believe me, its so much easier to fit the trans too the block off the engine. I cannot remember if you can use HI TACK sprayed on the gasket to keep it in place while attaching parts together.

My trans used paper gasket, never saw one that used a giant O ring....
mike

I own a '54 with hydramatic also plus some non-Chevy cars with that tranny. The tranny may shift a little hard compared to later aluminum/water cooled types but it's a great durable unit. Actually, I think there are 30 bolts holding the flywheel to torus. Before disassembly be sure to mark both pieces so they go back together exactly same (balance!) The narrow paper gasket is readily available and must be fastened to the torus with aviation permatex, let it set, coat the mating surface lightly with permatex and reassemble. I have always done this with engine-tranny out of vehicle and never had a leak. Trying to line the units for bolt up IN vehicle- not me!
If you have it apart take a good look at the flywheel ring gear and replace it if it's chewed up-yes, their available too. The starter motor is special for Chevy/GMC and nearly impossible to find. Don't lose it!

The Pontiac, Olds, Rolls, etc versions did have more bolts and a paper gasket. The truck (at least the half ton in my truck) had 18 bolts and a large "squared off" O ring. The "flywheel" will not have a replaceable ring gear as a manual transmission flywheel does. You also need to make sure and seal the area between the crankshaft flange and the "flywheel" or torrus housing front. You will also find a plate that says basically the trans and engine are mated at the factory but with normal runout checks, a different engine can be used. The booklet that I linked to earlier is one of a series of 7 service booklets for 54 Chevy trucks. The rest are in the same location. Check them all out.

The 1/2 ton Hydamatic had the same ratios as used in 6 cyl. Hydra. cars
!st 3.82 to 1
2nd 2.62
3rd 1.45

The 3/4 and 1 ton trucks were geared lower
4.70 to 1, 3.03, 1.55

The lack of a torque converter required a very low 1st gear.

We had a 1954 1/2 ton parts truck with hydramatic. It had harsh shifts but stood up well. I believe the truck unit had higher pressures for more positive shifts.
The Hydra. worked best behind a larger V-8 engine.

Thanks very much to everyone for all the info -- very helpful.

I have the engine out, after draining the tranny and torus, and am now searching for a new O-ring -- so far no luck. FS does not have, they tell me.

I suspect I may have to just coat it with gasket-maker and re-assemble, but would prefer new O-ring for sure.

Oh the joys ... !

If you cannot find it anywhere else, contact www.areds.com
they will have the parts you need as well as offering a rebuild service for the torrus cover if the seal surface areas are worn or damper springs are broken.

Many thanks -- will check them out.