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Projects 1951 Dodge Coronet

Discussion in 'The Hokey Ass Message Board' started by Joseph Roeker, Jul 24, 2014.

  1. Joseph Roeker
    Joined: Jul 24, 2014
    Posts: 4

    Joseph Roeker

    Hello Everyone,

    This is my first thread, I apologize if I am posting in the wrong place.

    My mom just bought a 1951 Dodge Coronet home. The car appears to be completely original with the L6 flathead in it. My Dad and I are into Chevy Small Blocks and we have been in the street rodding hobby for 20 years. We have never worked on any original flatheads before.

    The engine in this Dodge starts up very well but due to a bad fuel pump we haven't ran it very long. The fuel pump is on order and will be here next week. I am planning to change the engine oil because I would guess it hasn't been changed in years.

    ---What type/weight of oil do you suggest.

    I have been researching the gyro-matic transmissions and noted that some websites mentioned checking the fluid in them.

    ---How do you check the fluid and where do you add the fluid? What type of fluid would you put in it?

    If you Mopar guys have any suggested things to check before driving it, feel free to let me know

    Thanks for your time! It is greatly appreciated!
    Joseph
     
  2. Tim Keith
    Joined: Jan 1, 2010
    Posts: 65

    Tim Keith
    Member

    I think the Gyro-matic semi-automatic transmission uses 10 wt oil that you can get at Tractor Supply . These transmissions are usually dependable. There is removable panel under the floor panel to access the transmission - there is on my '47 De Soto with a similar transmission. I've heard that the Gyro-matic can be replaced with a 3 speed + R-10 overdrive from a '53 Dodge 241 hemi as a complete bolt-in, not to say you'd want to do that.

    You should check out the www.p15-d24.com site
     
  3. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,657

    Rusty O'Toole
    Member

    There is a lot of info on these cars on the AACA boards. They are well covered in the Dodge section, and the transmission in the Chrysler section.

    http://forums.aaca.org/

    No special oil required, ordinary 10W30 is fine, or Rotella 15W40 if you want to be pernickety.

    The Gyromatic is Dodge's version of the Fluid Drive and M6 semi automatic. Also called Tip Toe Shift in DeSotos and Fluid Drive in Chryslers, but all the same trans.

    The Fluid Drive unit is separate from the trans. It is checked through a hole in the floor boards. Below the dash board, on the right side of the trans tunnel. Roll back the carpet, remove the plate from the floor. You will see the bellhousing, pry out the round plug and bump the key until the plug comes into view. Unscrew and top up the oil with a funnel until it drips out. PS stuff a rag around the hole before you unscrew the plug so you can't drop the plug inside the bellhousing.

    The trans is like a standard trans, can be checked and filled the same as a standard trans, under the car. There is a pipe plug on the right side about 1/3 the way up.

    Use TDH tractor fluid, ISO22 or ISO32 grade. TDH stands for transmission, differential and hydraulic fluid. You can get it at Walmart, farm stores, and auto parts stores. Or #10 motor oil. Same for both trans and Fluid Drive.

    Complete instructions can be found in the Chrysler board linked above. Do a search for Fluid Drive, there were a couple of long threads in 2008 that are especially informative.

    Driving technique is a little different, like driving an automatic except you need the clutch to shift into gear when starting out, after that you don't need the clutch.

    I like to start the engine and warm it up for a minute. As soon as it idles down, step on the clutch, shift into High range and release the clutch, with the hand brake on. Release the hand brake, step on the gas and go someplace. When you get going 14MPH or more, lift off the gas, you should hear a soft *click-clack* from under the floorboards and you are in High gear. When you stop, the trans will automatically shift down, when you take off, lift off again when you hit 14MPH and it will shift up.

    2 things if you are new to old Chrysler products: watch out for left hand threads on the left side wheel bolts, and positive ground battery.

    The engine and trans are simple, reliable and usually trouble free. Transmission problems can usually be fixed for nickels and dimes. Most problems are broken or frayed wires, low on oil, or contacts need cleaning. 9 times out of 10 you can have them working perfect in a couple of hours if you know how.

    Engines too, are easy to fix, and parts are available cheap.

    If you want to keep it original you will find more sympathetic ears at the AACA forum.
     
    Last edited: Jul 25, 2014
  4. BuiltFerComfort
    Joined: Jan 24, 2007
    Posts: 1,619

    BuiltFerComfort
    Member


  5. George
    Joined: Jan 1, 2005
    Posts: 7,724

    George
    Member

    Assuming this is a sludged up high milage engine, don't put diesel oil in it, it's highly detergent & could cause a bunch of sludge to come loose that might clog up the oil pump pick up. Also if it's high milage you probably don't have to worry about the ZDDP-zinc controversy. 10W-30 would probably be OK, Accel brand 10W-40 sold @ Wal-Mart is SF & has zinc if you want to run oil with zinc in it.
     
  6. Joseph Roeker
    Joined: Jul 24, 2014
    Posts: 4

    Joseph Roeker

    Rusty,

    I have been researching the forums a little today. It appears you are very well respected and knowledgable when it comes to these old Dodges.

    I am curious, where is the engine oil filter located and what type of filter do you replace it with? It appears from the forums that the filter is in a canister.

    Also do you suggest draining the trans and the Fluid Drive unit? Or do you just add when needed?

    How well do these engines stay cool? I think my mother wants to drive it to Back to the 50's car show next summer. Do they run cool in stop and go traffic? Would it help to do a radiator flush?

    Thanks for all your help! I appreciate it a lot!
    Joseph
     
  7. George
    Joined: Jan 1, 2005
    Posts: 7,724

    George
    Member

    Try www.rockauto.com for the oil filter, witch is in a round can on the side of the engine. top unbolts
     
  8. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,657

    Rusty O'Toole
    Member

    The oil filter, if it has one, is a separate one bolted to a bracket on the left side of the engine near the starter. They were an add on accessory, various companies made them.

    The filter elements are still available at NAPA and other good parts stores.

    Trans oil is supposed to be changed every 10,000 miles. There is a drain plug on the bottom of the trans. The Fluid Drive is supposed to be checked and topped up every 10,000 miles but it never needs to be changed.

    When they are in good shape, they run cool in all conditions and all weathers. Unlike certain other flatheads (Ford) that were known for overheating.

    There is supposed to be a tin shield over the fuel pump. If it is missing, heat from the exhaust manifold can cause vapor lock. The shield is a simple piece of tin, bent into a J shape.

    I would blow out the radiator from behind with an air hose to remove dead bugs and dirt. Flushing the rad won't hurt if the rad is good, but could reveal old leaks by removing lime that is plugging them up.

    If you want to do a flush fill the cooling system with fresh water and a bottle of CLR calcium, lime and rust remover. Drive around for a couple of days, drain and flush.
     
  9. Joseph Roeker
    Joined: Jul 24, 2014
    Posts: 4

    Joseph Roeker

    Last night when I stopped at the shop, my dad requested that I ask about a screen or vent that is located on the underside of the car on the transmission or the fluid drive case. I believe my dad said it was rectangle shaped and he noted that it was plugged full of old grease and dirt. I haven't looked at it yet so I am unsure how to further describe it. We would like to know how to pull it apart or clean it without damaging anything. I am planning to look for the shop manual at my local library today.

    I have attached a couple photos that they took when they bought the car. The last photo is of our shop with the 39 Chevy that my dad and I did several years ago. I am planning to buff the 51 Dodge next week because the paint surface was very oxidized and I think it will look pretty awesome if we leave it once it is buffed out. Let me know what you guys think
    Thanks for your help.
    Joseph
    1951 Dodge front.jpg 51 Dodge Side View.jpg Shop.jpg
     
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  10. 73RR
    Joined: Jan 29, 2007
    Posts: 7,175

    73RR
    Member

    The screen is the air-cooling vent for the fluid coupling.
     
  11. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,657

    Rusty O'Toole
    Member

    The Fluid Drive is air cooled, if you clean off the screen it will help keep it cool. The Fluid Drive is a sealed unit, it builds up pressure when it gets hot and there is nowhere for it to go. In extreme cases it can blow the seal. I have never heard of this actually happening, extreme heat would be like towing a trailer up the Rocky Mountains with the gas pedal to the floor in August.

    As I said, I have never heard of one blowing up, but it can't hurt to clean the screen and let it get some air.

    Could you brush it off with a wire brush and blow clean with compressed air?
     
  12. Tim Keith
    Joined: Jan 1, 2010
    Posts: 65

    Tim Keith
    Member

    How To Service The Hydraulically Operated Transmission
     
  13. Joseph Roeker
    Joined: Jul 24, 2014
    Posts: 4

    Joseph Roeker

    Thanks for the video Rusty, we will be checking it over before driving anywhere. The fuel pump will be getting installed tomorrow.

    I noted that the car has a 12 volt battery in it and it starts very easily. We also noted that the headlights and some of the rear lights weren't working properly. Could this be because they were never converted to 12 volt? What does it take to convert the car over to 12 volt. I was told yesterday by someone at a local car show that you have to use "runts" for the dash instruments. Do you have to switch all solenoids and relays, ect? Or do the originals work? I was told that the original 6 volt wiring will work just fine. I am guessing the battery has been in the vehicle for a while but I am unsure how long. Do you have to run a new alternator/ generator? I would assume so....
    Thanks for any ideas.
    Joseph
     

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