Join Shelby Forums Today

66 GT350 Drive Train

Discussion in '1965-1970 Shelby Mustang GT350 & GT500' started by tommyleea, Sep 14, 2007.

  1. Sep 14, 2007 #1
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
    Good Morning..I have a few questions concerning the tranny and drive shaft for a 66GT 350. I purchased my car in 1972, and it has been sitting until now. I am getting it road worthy again. I am replacing the ujoints, which I assume to be the originals since they have what I will call a metal band on them to hold them together? Anyway, I replaced the ujoints, but there is no give in the drive shaft when installing it. It is not like I can slide the yoke into the tranny, and then have room to slide it back into the differential. I have to actually pry the shaft into place. It was very difficult to remove also, but I thought maybe that was just from sitting for so long. Are there any identifying marks on the tranny and driveshaft so I can verify if the parts are correct? The driveshaft is aluminum, and has a yellow or cream stripe, and a black or purple stripe just about in the middle of the shaft. Colors are faded so hard to tell exact colors. I am sure there are some numbers on the tranny, but I haven't examined it yet. Any help would be appreciated. It is a 4 speed..

    Tommy:confused:
     
    Last edited: Sep 14, 2007
    tommyleea, Sep 14, 2007
    tommyleea, Sep 14, 2007
    #1
  2. Sep 14, 2007 #2
    66-68Shelby

    66-68Shelby Active Member

    Posts:
    25
    Likes Received:
    0
    Joined:
    Feb 7, 2006
    Location:
    Jax, Fl
    The transmission should be a T 10. Depending on the car number early aluminum later cars cast iron. You can identify a T 10 by the side cover on the drivers side that unbolts. The side cover has the shift rods. If it was replace usually by a top loader the shift rods come right out of the case instead of the side cover. The drive shaft dosen't sound right as I have never seen a 66 with an aluminum drive shaft and it sound like the unit is too long. Hope this helps.
     
    66-68Shelby, Sep 14, 2007
    66-68Shelby, Sep 14, 2007
    #2
  3. Sep 14, 2007 #3
    gjz30075

    gjz30075 Well-Known Member

    Age:
    74
    Posts:
    87
    Likes Received:
    1
    Joined:
    Jan 6, 2006
    Location:
    Roswell, Ga
    Sounds like a slight spline count mismatch. Can you look inside your trans tailshaft and see the shaft with the splines and count them? Compare, then, to what's in the yoke of the driveshaft.
     
    gjz30075, Sep 14, 2007
    gjz30075, Sep 14, 2007
    #3
  4. Sep 14, 2007 #4
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004


    I didn't count the splines, and I could be wrong, but I would think if the spline count was off; then the yoke wouldn't engage with the tranny output shaft. The tranny is a T10.
    Tommy
     
    tommyleea, Sep 14, 2007
    tommyleea, Sep 14, 2007
    #4
  5. Sep 15, 2007 #5
    zrayr

    zrayr Well-Known Member

    Posts:
    446
    Likes Received:
    11
    Joined:
    Oct 30, 2005
    Location:
    TX
    the driveshaft is definately not original. what is the length from u joint center to center? Originals were just under 50 inches. An inch or so "free play" is a must.
    Did you determine what transmission you have?

    Z. Ray
     
    zrayr, Sep 15, 2007
    zrayr, Sep 15, 2007
    #5
  6. Sep 15, 2007 #6
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
     
    tommyleea, Sep 15, 2007
    tommyleea, Sep 15, 2007
    #6
  7. Sep 15, 2007 #7
    zrayr

    zrayr Well-Known Member

    Posts:
    446
    Likes Received:
    11
    Joined:
    Oct 30, 2005
    Location:
    TX
    I've had both the T-10 & a toploader in my '66, they were the same length. So that shouldn't be an issue re driveshaft length. Have you measured the driveshaft in question yet?

    Unless you want more originality, the aluminum driveshaft you have will be a performance upgrade. Just have it cut down to the correct length.

    Z. Ray
     
    zrayr, Sep 15, 2007
    zrayr, Sep 15, 2007
    #7
  8. Sep 15, 2007 #8
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
    Thanks for the inputs. I haven't measure the driveshaft yet. Maybe I can get to it tomorrow.

    Tommy
     
    tommyleea, Sep 15, 2007
    tommyleea, Sep 15, 2007
    #8
  9. Sep 17, 2007 #9
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
    OK..I measured the dirve shaft and it is 50 and 3/4 inch from center to center. I measured my 65 and it was also 50 and 3/4 inch from center to center. Now, the distance between the center of the front of the driveshaft and the back of the tranny extension housing on the 65 is 3 and 1/2 inch. The distance from the center of the driveshaft and the back of the tranny extension housing on the 66 is 2 inches. Both trannys are T10s. What is the deal here??

    Tommy
     
    tommyleea, Sep 17, 2007
    tommyleea, Sep 17, 2007
    #9
  10. Sep 18, 2007 #10
    zrayr

    zrayr Well-Known Member

    Posts:
    446
    Likes Received:
    11
    Joined:
    Oct 30, 2005
    Location:
    TX
    Tommy,

    My source for all this info is Tony Gregory's book "The 289 High Performance Mustang".

    The drive-shafts used in Hi-Po Mustangs were the 49 23/32" in length, (basically 49 3/4") they were shorter due to the snout of the 9" rear end being longer than the 8" unit used in all other Mustangs. The drive-shaft used in standard Mustangs with manual transmissions were 50 25/32" long (basically 50 3/4").

    So it would seem that the aluminum drive-shaft you are dealing with was set up for use in a standard, non 9" rear, Mustang. If you want to keep it, just have it cut down to the proper length. Any shop specializing in drive-train work can do this.

    Is the '65 you are referencing also a GT-350 ? In any case, don't drive yourself crazy comparing the two cars against each other. If the '65 has the right amount ( one inch =/- ) of free play, measured with the cars weight on the rear end; then you are OK there.

    Z. Ray
     
    zrayr, Sep 18, 2007
    zrayr, Sep 18, 2007
    #10
  11. Sep 18, 2007 #11
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
    Thanks for the info. It all makes sense now. The 65 is a convertable.
     
    tommyleea, Sep 18, 2007
    tommyleea, Sep 18, 2007
    #11
  12. Sep 22, 2007 #12
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
    Re: 66 GT350 Drive Train UPDATE

    Just an update on my driveshaft. Dropped it off Friday to have it shortened one inch. 135.00 to shorten, balance, and install new u-joints. I was very pleased. Will be finished Monday. Thanks for the info.

    Tommy:thumbup:
     
    tommyleea, Sep 22, 2007
    tommyleea, Sep 22, 2007
    #12
  13. Sep 22, 2007 #13
    zrayr

    zrayr Well-Known Member

    Posts:
    446
    Likes Received:
    11
    Joined:
    Oct 30, 2005
    Location:
    TX
    Re: 66 GT350 Drive Train UPDATE


    Be sure to replace the u-joint bolts & nuts while you at it, the driveshaft shop should have them.

    BTW, does your aluminum driveshaft have POLICE stenciled on it? The Crown Vic Police Interceptor models use a heavy duty 3.5" driveshaft that works great, (I have one in my GT-350) and is considerably stronger than the 3" aluminum one most companies sell for the Mustang.

    Z. Ray
     
    zrayr, Sep 22, 2007
    zrayr, Sep 22, 2007
    #13
  14. Sep 22, 2007 #14
    tommyleea

    tommyleea Well-Known Member

    Age:
    70
    Posts:
    129
    Likes Received:
    0
    Joined:
    Dec 22, 2004
    Re: 66 GT350 Drive Train UPDATE

    Good idea on the u-bolts. I didn't notice a stencil on it, but I will look when I get it back. It had a couple of stripes on it, but that's all I noticed at first glance. Thanks

    Tommy:D
     
    tommyleea, Sep 22, 2007
    tommyleea, Sep 22, 2007
    #14
  15. Sep 22, 2007 #15
    65gtfastback

    65gtfastback Well-Known Member

    Posts:
    193
    Likes Received:
    0
    Joined:
    May 19, 2006
    Location:
    @ Nashville
    What year Crown Vic's? That sounds interesting. Do the ujoints present a challenge for a swap?
     
    65gtfastback, Sep 22, 2007
    65gtfastback, Sep 22, 2007
    #15
  16. Sep 22, 2007 #16
    zrayr

    zrayr Well-Known Member

    Posts:
    446
    Likes Received:
    11
    Joined:
    Oct 30, 2005
    Location:
    TX
    Don't know what year of Crown Vic the driveshaft is from. Will crawl under there soon, and post all markings found...

    The u joints on the Police Interceptor driveshaft were different (heavier) than the Mustang driveshaft u joints. The driveshaft shop (Austin Drive Train) used Spicer # 5-134X u joints to mate the 2 different sizes. So the front yoke & rear end connections are unchanged. Hope that was clear.

    The shop also changed (shortened I think) the length of the driveshaft tube.

    Z. Ray
     
    zrayr, Sep 22, 2007
    zrayr, Sep 22, 2007
    #16

Share This Page