303M HydraMatic rebuild

[rustystud]

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Nice looking welds...

I had to learn welding during my apprenticeship training back in the day. Then years later I worked as a professional welder for 10 years in the Marine Fishing industry. I was also running a transmission repair shop out of my garage at nights. Oh to be young and strong again with all that energy !

 

[Mullaney]

I had to learn welding during my apprenticeship training back in the day. Then years later I worked as a professional welder for 10 years in the Marine Fishing industry. I was also running a transmission repair shop out of my garage at nights. Oh to be young and strong again with all that energy !

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Yes Sir. I had a pair of welders that I worked with back in the early 80's. They taught me a lot. I spent many hours learning. Yessir, at 65 myself I am starting to slow down a little...

 

[rustystud]

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Yes Sir. I had a pair of welders that I worked with back in the early 80's. They taught me a lot. I spent many hours learning. Yessir, at 65 myself I am starting to slow down a little...

Old age is not for the faint of heart !

 

[rustystud]

I finally finished the crane ! Working by myself and moving such heavy items (the main tube is 4" sch 160 DOM) is a real pain. I have to get very creative at times.
Now I just need to install the new transmission holder I made, and I can get back to the rebuild.

 

[rustystud]

Today I installed the reduction housing. That new crane I built made installing this housing a breeze !
Without it, I would have had to use a "cherry picker" or had another person help me. That housing is heavy !
My hand is healing up after my thumb injection last Monday. That shot hurt !

Make sure you use guide bolts to align the housing. Plus they help to hold the gasket in place. No trying to move the gasket after the housing is on.



The housing has landed !

After all the bolts are installed, make sure you install the rear pump oil filter, using a new gasket.

As you can see, I've been using stainless steel "Serrated Flanged" bolts for all my external fasteners. At least where I can. They have a superior holding power over regular bolts and lockwashers.

 

[rustystud]

Some might be wondering why I've been so slow in building this HydraMatic. One reason is parts availability. I've had to cannibalize several transmissions just to get enough "good" parts to finish this transmission. Another reason is I've had to have several parts "modified" or outright built. I'm still waiting on parts for the oil pan though I've found enough good parts to finish one. I'll post it later.
Then we come to my shop.
I'm physically unable to lift a lot of parts now. So I've been forced to build a new crane by my work bench. That took a few weeks to finish. Also my transmission holders are physically unable to hold the extreme weight of this transmission, so a new holder had to be made. That took a few days of welding and grinding and machining work to finish. I still haven't installed the holder due to my 17/32" drill bit being missing. I think "Gremlins" took it. I have ordered a couple of new ones, which I hope will arrive soon. I'm using 5/8" grade 8 flanged bolts to hold down the new holder. That entails a hole size of 17/32" for the 5/8" tap.
I was going to install the finished oil pan today, but the weight is so great I'm unable to turn the transmission on the holder. Not a good sign ! The new crane is attached to the transmission just in case the holder breaks.
We now come to the last part to install and that is the "valve body" . I've had problems with these valve bodies being rusted and valves pitted and stuck in their bores. Lots of broken and damaged parts here particularly the "throttle valve lever" . I only have one that is not bent. Every single one of these shafts from all these HydraMatic transmissions has been bent except one.
I took it to my machinist and since he is so backlogged he didn't even want to attempt to make one.
So, I need another machinist to try and make up some new shafts for me.
Once this last hurdle is accomplished I can than finish this transmission, and with all these good parts stockpiled possibly build a few more transmissions. We'll see what happens.

 

[m1010plowboy]

Some might be wondering why I've been so slow in building this HydraMatic.

........and the other reason is the holiday time North of the border.

What is the role of that "throttle valve lever"? Back in the day a fella at Reno Excavating was showing how something could get hung up. I recall some 2" ish long lever that was close to 3 round things with a role pin that would get sloppy so he had to bend something to keep it from binding.

My in-depth mechanical explanation is good for musicians so hopefully you can expand on the 'valve body' info.

 

[rustystud]

That lever, (which gets hit and bent all the time) gets a push from the rod attached to the Carburetor .
That tells the valve body how much engine power is being asked for. Full throttle tells the transmission to hold back on shifting or to downshift (depending on governor pressure) to keep the engine RPM's up for more power. Without the throttle valve the transmission would shift into high gear in seconds and you would be lugging down until the engine shut-off.
As a practical joke, we (meaning me and other apprentices) would disable the throttle lever, or on more modern transmissions the vacuum solenoid and sit back and watch the other older mechanics try and figure out what happened to their vehicles. Lots of fun until they got back at us by disabling our engines !
Trust me, it kept us on our toes !
Yes, that guy at Reno Excavating was looking at the throttle lever.
I contacted "Peashooter" to see if he could help machine some shafts, but he no longer has access to the good machines, plus he is recovering from shoulder surgery. Nasty business that. I know !
So now I need to find another quality machinist. What fun this project has been !

 

[rustystud]

Hey Dave (Plowboy) .
When does the snow usually leave your area ? In other words, when will it be safe to come up there ?
I'm thinking late spring early summer. Does that sound about right ?

 

[m1010plowboy]

Hey Dave (Plowboy) .
When does the snow usually leave your area ? In other words, when will it be safe to come up there ?
I'm thinking late spring early summer. Does that sound about right ?

After 100 years of family farming, research and weather record keeping, I have no idea.

In 2018 we were still on the ice mid April.

Usually ........frozen roads go away by April. It might snow into May but the pavement gets warm enough it's better than the 7 months of ice road trucking.

That leaves April (start of flood season), May (forest fires), June (blackflies and mosquitos), July (hail and tornadoes) Aug. (sweltering heat and more floods) September (Snow)

Black flies and mosquito month can be conquered with some netting and deet so that might be best time.

On the last deuce the local boys built, Soup lover and the Greek engineer came over to borrow this piece off my NOS trans. ......
......... Once again, the boys in 1950 were drawing this up saying........" Check out the look on the landscapers face when try to figure this out in the year 2025"......

........ I most certainly need to play with one much more to see how it functions 'properly'. Any info you provide on this little computer when the folks are trouble-shooting trans awareness is a bonus. Some people can look at this and map out the function, others are normal and like soup.

 

[rustystud]

After 100 years of family farming, research and weather record keeping, I have no idea.

In 2018 we were still on the ice mid April.

Usually ........frozen roads go away by April. It might snow into May but the pavement gets warm enough it's better than the 7 months of ice road trucking.

That leaves April (start of flood season), May (forest fires), June (blackflies and mosquitos), July (hail and tornadoes) Aug. (sweltering heat and more floods) September (Snow)

Black flies and mosquito month can be conquered with some netting and deet so that might be best time.

On the last deuce the local boys built, Soup lover and the Greek engineer came over to borrow this piece off my NOS trans. ......
......... Once again, the boys in 1950 were drawing this up saying........" Check out the look on the landscapers face when try to figure this out in the year 2025"......

........ I most certainly need to play with one much more to see how it functions 'properly'. Any info you provide on this little computer when the folks are trouble-shooting trans awareness is a bonus. Some people can look at this and map out the function, others are normal and like soup.

View attachment 940785View attachment 940786

So I guess I'll aim for June then.

Thats just a very simple normal valve body. On later car HydraMatics they got a little bit more
complicated. Of course not nearly as complicated as say an Allison 1000 series or worse yet a Chrysler 68RFE , or an GM 6L90E or any new transmission out there. The new 10 speeds are a real nightmare !
They all incorporate electric shift solenoids with all that corresponding electrical wiring.

 

[rustystud]

I finally installed my new transmission holder. Works great.
You can really see the difference between the hold-down bolts. This new holder will take that "303M HydraMatic" all day long !

 

[rustystud]

I also rebuilt the oil pan and installed it today.

I use some spray gasket on the fiber washers for the water side of the cooler.
Then I put some assembly grease on the cooler where the fiber washers will make contact.
Then install the cooler making sure you install the fiber washer, ring and nut on the discharge side.
Tighten down the nuts to help squeeze the washer in place.
Then loosen up the nuts and put on some Red Loctite.



Install the cover and gasket.

Install the filter and your done with the oil-pan.


When it's time to install the oil-pan on the transmission remove the rear bypass valve to check that the pick-up tube is in place on the oil pan.

Then reinstall the bypass valve and tighten it.


Now I just need to install the valve-body and this transmission is basically done.
So I better get on the phone and see who can reproduce the "throttle" valve shaft.

 

[rustystud]

Well my search for some machine shop to help fabricate the throttle lever shafts has proven futile.
Unless I want 1000 units or more, most shops don't even want to talk with me.
So that leaves me with using shafts from civilian HydraMatics. The problem there is, they too have a tendency to get broken ! Thou not as often as the 303M does.

I started tearing down the "governor" - "reverse blocker" units. The reverse pistons all had gunk behind them, so it's a good idea for anyone rebuilding their 303M Hydros to clean this unit well.
You first need to cut off the "pin" that holds in the reverse blocker piston and spring. Later you can use a 16d finish nail to go back in.
Remove the piston and spring (the spring will shoot out after you remove the pin so watch out).

Then you will need to clean-up the governor bore. I use a "brake cylinder hone" for this.

You need to remove all grooves from previous rings. Aligning this part is very critical for the longevity of the transmission, as it involves governor pressure. If the reverse blocker unit is not aligned correctly it will cause heavy grooving in the governor bore.
These two pictures show how the rings dug into the one side of the bore. This was after I honed it out too ! This unit had not been aligned correctly.
Putting a heavily grooved unit back in service can cause the new governor rings to break. Or the very least to leak severely.
Like I said earlier, you can use a 16d finish nail. Just cut and hammer the one end.


You might be wondering what the reverse blocker actually does. Here's a picture that shows how the blocker really "blocks" the manual valve from moving out of reverse.
The reverse piston when applied moves out of its bore to physically engage the lever which in turn blocks the manual valve.
In this picture you can also see I have installed the three tubes connecting the valve body to the reverse blocker assembly.

Just for grins and giggles I want to show you how the military valve body differs from a civilian unit.
The military valve body has a steel insert in the manual valve lever bore. This strengthens the housing while providing a solid surface for the shift lever to operate against. The Cadilliac HydraMatic also use's a Bronze bushing here, but the steel one is better for this application as it's support for the aluminum housing is far superior.


Later I will show the valve body going together and show you how to align the reverse blocker assembly.

 

[rustystud]

I search the internet and craiglist all the time trying to find parts for the HydraMatics.
One problem I have come across several times is the seller has some part that is NOS still in it's original wrapper or sealed box. The problem is these parts are almost 70 years old. The box or wrapper has allowed moisture in. The seller when asked to inspect the part will not open the box or wrapper. So your left buying a part in unknown condition.
Here's one of my recent purchases. This picture was taken "after" I used a "Scotch Bright" pad on it.

This is a critical part. The "oil delivery sleeve" holds the clutch housings and provides sealing for the clutches themselves. It must be in good condition.
Yes it was in a sealed box and wrapper, but 65 years of sitting who knows where has allowed moisture to enter and this rust to develop. I think I will be able to remove most of the rust without hurting the surface, but who really knows until you try. So you end up paying top dollar for an unknown item. This has happened so often I will no longer buy an item unless I get a really good deal on it.
I'm just putting this out there so you can be aware when buying parts, especially parts that are NOS.

 

[rustystud]

I promised to show you how to align the "reverse blocker" to the "governor" . So here it is.
You will need to buy or make up your own tool for this. There is no way to get around it.

After installing the four sealing rings, you will install the reverse blocker.
You will need to loosen the governor bolts and the reverse bocker bolts. Leave then hand tight. Than install the alignment tool shown here.
This will "square-up" the governor to the reverse blocker . Tighten the governor bolts to 15ft to 18ft torque and the reverse blocker to 10ft to 13ft . Remove the alignment tool.
I'll post dimensions of the tool later.
Now you can install the valve body by sliding it on the tubes of the reverse blocker.
I know I showed you the oil pan going on earlier. That was me trying to fit the pick-up tube I had to fabricate for the gear driven front pump. Sorry for any confusion.
I'm still messing with that tube.

I see I forgot the picture of the alignment tool in use. I'll post that tomorrow.