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Technical 1940 Mopar OD Transmission to 1949 Coronet swap question

Discussion in 'Traditional Customs' started by HXFOUR, Sep 15, 2021.

  1. HXFOUR
    Joined: Sep 27, 2020
    Posts: 16

    HXFOUR

    Hey y'all. Theres tidbits of info out there about these transmissions but nothing specific to my particular application.

    I have a 1949 Dodge Coronet Sedan w/ fluid drive, In Ontario Canada.
    Im putting in a newly rebuild 265 flathead from a 1953 Chrysler

    I bought a rebuilt/updated 1940 Borg Warner transmission with overdrive (I believe this is an R7) for a console shifter. Has everything I'd need. I'd like to put in this overdrive, and I have conflicting info. I know the R10 is better, but I cant find a rebuilt one for sale.

    I'll likely take out my transmission and put it side by side with this new one to see the differences but...

    1. Has anyone done this swap?
    2. Does anyone know the glaring differences in design between the fluid drive and the 1940 w/overdrive?
    3. If fabrication is involved, do you know what to expect?

    The rumours or information I've been told are
    1. The input shaft is different, Id need a longer one. (Not sure if true or false)
    2. The Bellhousing from my fluid drive will replace the bellhousing on the OD transmission. (not sure if true or false)
    3. Id need a long throwout bearing (Which I bought)
    4. Id need a new or shortened driveshaft. (I expect this)
    5. Some part between engine and trans gets reversed and it miraculously fits.

    Im very green with this car, or any car but Id like to try and understand what to expect and what Id need to do in order to make this happen. If its too difficult, id likely keep the fluid drive for now, and search for the R10.

    Any bit of help and all discussion is appreciated!
    Screen Shot 2021-09-15 at 3.58.13 PM.png
     
    Last edited: Sep 15, 2021
  2. choptop40
    Joined: Dec 23, 2009
    Posts: 4,231

    choptop40
    ALLIANCE MEMBER

    Lot easier to change the rear gear ratio.. are you doing a lot of long distance driving ? Also the 53 engine is 2 inches longer.. you’ll have to notch the front crossmember to clear the crankshaft pulley , re drill the mounting holes...I’ve done this before.. big pain .. it can be done..gather all your parts first if you decide to continue...also. Taller tire will give less rpm at higher speeds...molars rule my man...
     
    HXFOUR likes this.
  3. HXFOUR
    Joined: Sep 27, 2020
    Posts: 16

    HXFOUR

    Interesting. I was told the car is prepared for the 25" block as the car shell was for Canada (25") and USA (23"). The horns move, and rad moves up the 2" to pre existing holes. Engine then goes into existing mounts.
     
  4. choptop40
    Joined: Dec 23, 2009
    Posts: 4,231

    choptop40
    ALLIANCE MEMBER

    The engine front crossmember must of been factory notched for the Canadian models then.. Cool. Ok .. also the overdrive cable ...do you have that also ?
     
    HXFOUR likes this.

  5. HXFOUR
    Joined: Sep 27, 2020
    Posts: 16

    HXFOUR

  6. proartguy
    Joined: Apr 13, 2009
    Posts: 547

    proartguy
    Member
    from Sparks, NV

    Fluid Drive was offered a couple of different ways; one with a conventional 3 speed trans and another with the 4 speed M6 semi automatic. My ‘53 Dodge panel had fluid drive with a 3 speed trans. I installed a passenger car 3 speed trans with o.d. with the original truck bellhousing and fluid drive/clutch by using the longer original input shaft in the o.d. trans. Of course, the driveline had to be shortened. Worked out well with manually operated overdrive and fluid drive/clutch.

    To eliminate the fluid drive the easiest way is to use a conventional bell housing, throwout, etc.
     
  7. HXFOUR
    Joined: Sep 27, 2020
    Posts: 16

    HXFOUR

    Question - and I’m really green. The longer input shaft, does that require a transmission disassemble? I’ve been told I’d need it and it’s scared me a tad.
     
  8. proartguy
    Joined: Apr 13, 2009
    Posts: 547

    proartguy
    Member
    from Sparks, NV

    The input shaft can be changed by removing the front bearing retainer, the whole trans need not be disassembled. As I recall the roller bearings on the input shaft can be secured with grease to aid reassembly. Did this a long time ago, but as I recall it was no big deal.
     
    HXFOUR likes this.
  9. HXFOUR
    Joined: Sep 27, 2020
    Posts: 16

    HXFOUR

    You were right. Notched it. But it’s in there now! D90C4641-6D02-497B-8667-90008577FBCA.jpeg FF3ECB92-CEEA-4DDB-A5A6-D43388156BD8.jpeg
     
  10. 73RR
    Joined: Jan 29, 2007
    Posts: 6,710

    73RR
    Member

    I'll give ya bump for the evening crowd.
    You really need to go over to www.p15-d24.com for more info.
     
    Last edited: Oct 23, 2021

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