Important drive shaft question

Discussion in 'Technical' started by Rev Ron, Jun 12, 2017.

  1. Rev Ron

    Rev Ron Member

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    I have a 71 Comet GT with a 5.0. I've just taken out a T-5 and installed a C4. I am told by the tranny shop that I need a longer drive shaft. They say it needs to be 2" longer. When I took it out of the car to measure it, I see that when I push it fully into the tail shaft of the tranny, it goes in about 2 more inches & I can still place the u-joint into the rear end (with not much room to spare). So the tranny shop is on target... or are they? How much space should there REALLY be between the u-joint and the rear end? I know that there needs to be some room. Here are the measurements on my current shaft: 54' long, tip to tip; 45 1/4", center to center/ yoke to yoke; 42", shaft only; 2 1/4", depth of shaft (diameter, really?). Thanks for any experience you have and help.
     
  2. 71gold

    71gold Frank Cooper Supporting Member

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    there is a seal wear pattern on the yoke. compare it to the C-4 and see where it is running in the tail shaft.
    I've had my stock length Maverick small drive shaft behind a...C-4, AOD, T-5 and now behind a 700-R4 (w/front yoke change).
     
  3. Rev Ron

    Rev Ron Member

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    Yeah, but the question is: what length is my stock drive shaft? From what I read, some were longer and some were shorter, if not by more than 1-2 inches. My stock length drive shaft may be shorter than yours. Also, the wear pattern on mine has been from a T-5 and I have not driven my C4, so I don't know what it is. Thanks!
     
  4. rthomas771

    rthomas771 Member

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  5. Maverocket

    Maverocket Bob Williams

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    As a general rule you want 1"" of clearance between the yoke and output shaft. If you have a shaft with the correct yoke, slide it in till it bottoms out. Then measure the distance between the u-joint and the saddle on the rear end. If you have an inch or so you're good to go.
     
  6. 71gold

    71gold Frank Cooper Supporting Member

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    my point...measure the wear pattern on the driveshaft from the T-5 (yoke cup center to seal mark). then mount the driveshaft into the C-4 and check where it's at on the seal to the center of the yoke cup... that will let you know if it's deep enough.
     
  7. 71gold

    71gold Frank Cooper Supporting Member

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    get this figured out yet?
     
  8. Rev Ron

    Rev Ron Member

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    Ok gents, here is the final word on this. You gotta make sure the shaft is long enough so it won't kick out when you hit the pedal. I could not find a drive shaft locally, on this website or on Ebay, so I had to go to my local drive shaft shop and have one made. Then again, if you buy it on Ebay, you never know what you get. After $300 cash, I had a new one (I will sell the old one). They told me that the 2 1/4" steel shaft that the factory used is not made anymore, so I had to upgrade to a 2 1/2 shaft with new u joints. Then again, I notice from the factory spec sheet that some later Mavericks/Comets had a larger drive shaft. I hope this helps some of you as you wrestle with some of the same questions. It is a good feeling to know I can now kick it & there will be no surprises.
     
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  9. mavdog71

    mavdog71 Member

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    Ron Check with Coleman Racing Products you can buy a all new aluminum drive shaft with u joints shipped to your door for less than 300.00 . They make drive shaft from 32'' to 65'' in 1/2 increments for the same price . Order one for my son's car good stuff .
     

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