303M HydraMatic rebuild

[rustystud]

It was raining like "a cow pissing on a flat rock" today so I decided to install the front and rear servos .
During this I realized I had forgotten to remove the check ball and spring in the modified front servo I'm going to use. I posted about this in post #121 . I showed what needed to be modified on the front servo to fit our 303M transmission. I also went back and corrected some information I posted last summer.
I also found out about the "A" and "B" MWO modifications. If I had just read my manuals instead of skim read them I would have found this out. Instead I just skim over stuff I think I already know, like "yeah yeah I know this blah blah blah" . Turns out I really need to "read" the manuals and supplementals I own !
The A and B MWO is converting the 302M transmission into a 303M unit.
When the first HydraMatics where installed in the M135's they thought they could get away with just using three clutch plates in the front drum assembly ! The "civilian cars" had five clutch plates at this time !!!!
What were they thinking !!!!
They also replaced the rear servo unit with one that dumped fluid faster giving a faster band apply.
Now back to my install of the servo's.
First off you need to install the rear "discharge tube" into the back of the case. You will need to make sure it is fully engaged. It will be a snug fit.
Second, partially install the front servo, leaving a gap between the servo and main case of about 1/4" . That will allow you to fit the rear servo in since it needs to go into the connecting tube between the two servos and also fit into the rear band socket.
Make sure the front servo tube is fitting securely into the front pump and the servo apply pin is fitting into the front band socket. Also the "discharge tube to the back of the case needs to be installed into the front servo at this time.
Thirdly, install the rear servo. Making sure it is fitting into the front servo connecting tube and the rear band socket. Install all the bolts and slowly turn them down until all assemblies are fully seated. Then torque them down, 28 to 33 ft Ibs .

 

[rustystud]

I'm going to spend tomorrow thinking of a way I can install some kind of return spring for the reduction piston. There just has to be a way this can be done. Then again maybe there isn't any other way. Well see.

 

[USMC 00-08]

Well Tom "Wolboldt" has not been seen since September 24, 2017 .
So, "USMC 00-08" if you can get his phone number that would be great.

Working on getting his phone number. Will report back.

I decided to install the front and rear servos .
During this I realized I had forgotten to remove the check ball and spring in the modified front servo I'm going to use. I posted about this in post #121 . I showed what needed to be modified on the front servo to fit our 303M transmission. I also went back and corrected some information I posted last summer.
I also found out about the "A" and "B" MWO modifications. If I had just read my manuals instead of skim read them I would have found this out. Instead I just skim over stuff I think I already know, like "yeah yeah I know this blah blah blah" . Turns out I really need to "read" the manuals and supplementals I own !
The A and B MWO is converting the 302M transmission into a 303M unit.
When the first HydraMatics where installed in the M135's they thought they could get away with just using three clutch plates in the front drum assembly ! The "civilian cars" had five clutch plates at this time !!!!
What were they thinking !!!!
They also replaced the rear servo unit with one that dumped fluid faster giving a faster band apply.

Ok. I had mentioned in post #104 that my transmission had the A and B MWO. So I have the 303M but would still need to modify the front servo like you have at the point it ever needs rebuilt?

 

[rustystud]

Working on getting his phone number. Will report back.



Ok. I had mentioned in post #104 that my transmission had the A and B MWO. So I have the 303M but would still need to modify the front servo like you have at the point it ever needs rebuilt?

You don't need to modify the front servo if you don't want too. The stock servo works just fine.
The modified servo I'm using will give me engine braking abilities and it has a greater surface area on the piston for more holding power.

 

[rustystud]

Spent the day cleaning up the "output shaft bearing retainer" and apply piston.
I also ran my left index finger through the wire wheel on my grinder !!!
I took off about 1-1/4" of skin. Lots of blood, no fun at all.
Need to pay more attention when cleaning parts on the wire wheel !

 

[m1010plowboy]

Spent the day cleaning up the "output shaft bearing retainer" and apply piston.
I also ran my left index finger through the wire wheel on my grinder !!!
I took off about 1-1/4" of skin. Lots of blood, no fun at all.
Need to pay more attention when cleaning parts on the wire wheel !

We could have sat on youtube all day and not get injured. Having ambition can be hazardous. One ambitious fella I worked with was using a wire wheel to paint prep our trailer when he let out a scream. If those wires aren't grabbing a finger and pulling it in, they are coming off at high speeds and lodging in various body parts. In this case, the crouched position with the legs spread open allowed that tiny wire to penetrate the coveralls and jab itself right into the swimmer holding sac. That's right, .....while we're waiting for your skin to grow back, we can picture that poor fella in Emergency.....announcing that he had a wire lodged in his purse.

For those chiming in that have not used a wire wheel on a grinder, even after decades of experience, they can still get you. Here are a few tips but my first tip is, Get Rich and pay someone to run your grinders. https://www.ccohs.ca/oshanswers/safety_haz/abrasive_wheels/safeuse2.html

 

[rustystud]

We could have sat on youtube all day and not get injured. Having ambition can be hazardous. One ambitious fella I worked with was using a wire wheel to paint prep our trailer when he let out a scream. If those wires aren't grabbing a finger and pulling it in, they are coming off at high speeds and lodging in various body parts. In this case, the crouched position with the legs spread open allowed that tiny wire to penetrate the coveralls and jab itself right into the swimmer holding sac. That's right, .....while we're waiting for your skin to grow back, we can picture that poor fella in Emergency.....announcing that he had a wire lodged in his purse.

For those chiming in that have not used a wire wheel on a grinder, even after decades of experience, they can still get you. Here are a few tips but my first tip is, Get Rich and pay someone to run your grinders. https://www.ccohs.ca/oshanswers/safety_haz/abrasive_wheels/safeuse2.html

The worst one I had was one got stuck in my eye. I was wearing safety googles too ! Somehow it wound itself around the googles air holes and got me.


All I can say is thank the good LORD for lidocaine ointment !

 

[rustystud]

Today I finished with the servos and started with the reduction unit.
If you follow the book and have the special adjusting tools it is pretty straight forward. If you don't have the adjusting tools it gets harder.

The first thing you do is adjust the tool. You need 1/8" of the adjusting nut exposed. First photo. Then install it in the top of the servo after removing the pipe plug. After hand tightening the tool use a wrench to hold the main body of the tool and using another wrench tighten five turns the adjusting nut on the tool Then you tighten the band adjusting bolt until that little washer on top of the tool just starts to loosen. Then you just tighten the band adjusting bolt jam nut and your done for the front servo.


The book goes into detail about the "band adjusting rod" which I just throw away. Their usually broken and really don't do anything.
Now if you don't have the adjuster tool you can still adjust the front band by engine RPM which is actually the best way to adjust the front band. Just get the band adjustment close before buttoning up the transmission. Apply air pressure to the front servo and if it grabs the drum so that you cannot turn it, call it good. That's close enough for the RPM adjustment to work.
Some might ask how adjusting the front band by RPM's is best, well you never know how the band will grab the drum. Sometimes newer bands will grab really fast so they need less adjustment. Other times older bands will need more adjustment to hold. The RPM way is the only way to truly adjust for any situation. I'll post it for those who want to know how to do it later. Too much writing. Maybe I'll just cut and paste it.

Now onto the rear servo adjustment.
If your lucky, the "rear servo actuating lever" is working correctly. Using the checking gauge adjust the band adjusting screw until there is a gap of about 3/8" to 1/2" between the gauge and the servo actuating lever. Than just apply and release air pressure to the apply passage (where the valve body bolts too) . This action of applying and releasing air pressure will cause the automatic band adjuster to tighten the band. Then just finish up once the automatic band adjuster stops by tightening the band adjuster bolt until you have a gap of 1/8" between the gauge and servo apply rod.
Now if you don't have the rear servo gauge, just apply air pressure until the automatic band stops and call it good.

 

[rustystud]

The rear shaft bearing support is the only part I use grade 8 bolts on. I also use "Nordlock" washers on the bolts. This part is the one part you do NOT want coming loose !


After the support is bolted down and torqued (33 ft Ibs to 38 ft Ibs. ) it's time to install the piston. First off install the rubber seal to the support and then the piston being careful to not "roll" the seals. Make sure the seals are fully seated into the gooves. Use lots of assembly lube too.
Once the seals are in, place the piston on top of the guide studs ( do not attempt to install the piston into the guide studs yet) . Using your fingers, gently run them around the outer rim of the piston pushing the seal in. Use both hands. You will feel the piston start to drop and touch the guide rods. Now slowly turn the piston (without putting any pressure on it ! ) until it locks into the guide rods. Now if you chamfered the piston holes like I told you too this should happen without any problem. It should now drop into it's bore. Push down on the piston to make sure it is fully seated.

I usually test the piston at this time. First, I put "ViseGrip" pliers on the housing to prevent the piston from flying out of it's bore. Then I gently apply air pressure to the oil supply passage and watch the piston move. There are four oil passages on the outside face of the piston to lubricate it when it comes into contact with the "driven cone" . Those passages will blow air out so don't worry about that. Just make sure the piston raises up.