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4 Speed Transmission Crossmember?

Discussion in 'Early CJ5 and CJ6 Tech' started by Buildflycrash, Nov 4, 2020.

  1. Nov 6, 2020
    Buildflycrash

    Buildflycrash More or less in line 2020 Sponsor

    Gulf Breeze FL...
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    I think I understand. In your first photos above, the photo in the upper right shows the oil pan and front drive shaft with the crossmember behind but not the skip plate, right? The lower photo shows the skid plate installed. The skid plate is mounted to the bottom of the frame and does go all the way across, correct?
     
  2. Nov 6, 2020
    Dphillip

    Dphillip Member 2020 Sponsor

    Omaha NE
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    Exactly correct!
    It’s really nice to be able to quickly drop the skip plate with 4 bolts and still have the drivetrain supported by the cross member.

    Crossmember skid plate off.
    The black plate in the foreground is a skid plate silicone glued to the bottom of auto trans oil pan.
    625546FF-F8B3-4E8E-A39F-0334D9001662.jpeg
     
    Last edited: Nov 6, 2020
  3. Nov 9, 2020
    Buildflycrash

    Buildflycrash More or less in line 2020 Sponsor

    Gulf Breeze FL...
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    What is the thickness of the steel on the main skid plate? Same on Transmission?
     
  4. Nov 9, 2020
    Dphillip

    Dphillip Member 2020 Sponsor

    Omaha NE
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    Both are 3/16 plate steel.
     
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  5. Nov 12, 2020
    BadGoat

    BadGoat How High Can You Climb?

    Northern Virginia
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    I managed to reuse the stock cross member for my SM465 by redrilling the holes for the trans/t-case mounting points and the frame holes. I made sure the t-case torque support lined up correctly before drilling.



    Mike
     
    Last edited: Nov 12, 2020
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  6. Nov 24, 2020
    73 cj5

    73 cj5 Not ready for the junkyard yet 2020 Sponsor

    Mississippi
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    Here is a cross member on a later CJ5. Angle iron and plate.
    [​IMG] [​IMG]
     
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  7. Nov 24, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    Wow. A Rockwell T221 t-case. Sweet!
     
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  8. Nov 24, 2020
    73 cj5

    73 cj5 Not ready for the junkyard yet 2020 Sponsor

    Mississippi
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    I said the same exact thing when I saw it. I wanted the transfer case but finding something with a low output like that would be difficult. The Jeep belongs to a MS State football coach so money wasn't an issue so I hooked the guy up with a ton of new parts and a power steering/tilt column swap. I got a free SM465 out of the deal and didn't have to lift a finger. (y)
     
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  9. Nov 25, 2020
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    I've worked on one of these Rockwells in an early '60s Chevy and wasn't impressed. It was super loud on the road, and I never could get it to hold oil. You think Jeeps leak? The Rockwell needed refilling weekly, and that after resealing it a couple times. I gave up. They do have a neat low driveshaft output though.
    -Donny
     
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  10. Nov 25, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    They show up locally sometimes for cheap. I’ve read that it’s not too difficult to turn them into a dual rear output, with the extra output running off the front drive. I’ve kicked around the idea of running one in my truck with the second rear output powering a rear PTO winch. That truck already has leaks, what’s one more? :D
     
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  11. Nov 25, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2021 Sponsor 2020 Sponsor

    Denver, CO
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    Hey Scott - are you still thinking of bending your own tubing to make the cross-member? If so, a few questions:
    1) are you planning on putting some sort of mount for the D18 snubber?
    2) How are you planning to mount the brackets along the inside of the frame rail? I guess what I am asking is are you planning on mounting 'inside' the channel, or would it be worth adding a bit of boxing on the inside of the frame to then mount the brackets?
    Keep us posted - I am going to be in this same boat with the sm465 in the willys - but I think its going to be even harder as the frame rails are not parallel like they are in the cj...
     
  12. Nov 25, 2020
    Jay's WWII Jeeps

    Jay's WWII Jeeps Member 2021 Sponsor 2020 Sponsor

    Napa CA
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    On my build I'm using a stock 4sp CJ5 cross member that bolts directly to the frame (no spacers). It puts the bottom at same height as a stock t90. It's a Ford T18 and a Dana 18.

    Jay
     
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  13. Nov 25, 2020
    RATTYFLATTY

    RATTYFLATTY I think you need a little more throttle

    Central MN
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    Not trying to hijack someone else's answer I used a piece of angle to sit on the top of the bottom lip of the drivers side frame rail and a spring bushing style mount on the bottom of the passenger side. I haven't incorporated a torque mount into it yet.

    IMG_1359 (2).JPG
     
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  14. Nov 25, 2020
    Buildflycrash

    Buildflycrash More or less in line 2020 Sponsor

    Gulf Breeze FL...
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    I am going to box that section of frame and use bushings on the ends of the pipe. The mounting location of the bushings will be on the boxed section inside the rails. I plan on using a heavy piece of angle iron to direct mount the transmission to the pipe.
    Should be done this week but subject to change. :D
     
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  15. Nov 25, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2021 Sponsor 2020 Sponsor

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    That was what I was kind of thinking....still wondering about the transfer case mount, but if the vibration isolators are at the ends of the cross-member where it mounts to the frame, and the transmission is hard mounted to the cross-member, maybe the D18 snubber mount isn't all that important?
     
  16. Nov 25, 2020
    ITLKSEZ

    ITLKSEZ Volvophilic

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    This is going to put a lot of stress/leverage on the trans mounting bolts. The motor mounts will allow a lot more twisting motion than the crossmember bushings out at the frame rails, and that difference will break bolts or crack the mount. I’d really suggest working in flexible mounts at the connection points if you can, unless you plan on changing your motor mounts to match the rigidity of the crossmember bushings. It all needs to move at the same rate, or the stiff spot will give.
     
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  17. Nov 25, 2020
    Buildflycrash

    Buildflycrash More or less in line 2020 Sponsor

    Gulf Breeze FL...
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    Thanks
    Was trying to save some ground clearance. I have a new transmission mount so I’ll definitely consider using it.
     
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  18. Nov 25, 2020
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    Didn't get a chance to put pics up yet, but I use angle iron to make the frame mounts the bent tub connects too. Rubber Isolators on the tranny and TCase mounts with it. I 'should' be able to take pics Saturday of the '49 setup. The '63 doesn't have the TCase isolator on it yet, but it's done the same way.
     
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  19. Nov 26, 2020
    zinertia2

    zinertia2 "and which part are you keeping?" 2021 Sponsor 2020 Sponsor

    San Diego
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    Dphillip
    Have you noticed any issues between the different elasticity from the motor mounts to the transfer case crossmember bushings?
    Dennis
     
  20. Nov 26, 2020
    Dphillip

    Dphillip Member 2020 Sponsor

    Omaha NE
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    None whatsoever!
    The motor mounts are rubber, the transfer case mount is polyurethane and the crossmember bushings are polyurethane. It’s a solid set up with no movement to the drive train under load. I also do not have a torque arm from the transfer case to the crossmember. Never felt the need for one since I don’t have tons of horsepower turning giant tires.
     

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