Turbo 400 leaking through the weep hole on the driveshaft yoke

Discussion in 'The "Juice Box"' started by buick64203, Feb 24, 2016.

  1. buick64203

    buick64203 Just plum crazy Staff Member

    So the turbo 400 in my beater GS is leaking through the weep hole of the driveshaft yoke. What needs replacing?
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Last edited: Feb 25, 2016
  3. DaWildcat

    DaWildcat Platinum Level Contributor

  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

  5. DaWildcat

    DaWildcat Platinum Level Contributor

    I never actually owned one with the o-ring on the output shaft, but I did have a car with the wrong yoke...yup, one with that little air vent. Mine leaked too, because there was no o-ring provision on the output.

  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I spoke with Jason this morning. I guess we will see if he has the wrong yoke, or the O ring is worn/missing. I'm thinking wrong yoke.
  7. buick64203

    buick64203 Just plum crazy Staff Member

    Well, the trans is original to the car but I found out this past weekend that the rear is an 8.5, not an 8.2. Which means that the driveshaft would of gotten swapped as well. So Im thinking the yoke that is on there came with the driveshaft.

    Now If the output shaft had an accommodation for an O ring, that would mean the inside of the yoke would have a smooth area with no splines for the O ring to slide on correct? I seem to recall no such area on the inside of the yoke when I pulled the driveshaft a couple months back. The splines went to the edge of the yoke.

    Just for giggles, I looked up the GM number for the yoke in my parts book. According to the parts book, its supposed to be #7801551.

    BRUCE ROE Well-Known Member

    That is about it. A TH400 output shaft with an O ring will work with either type yoke. An
    output shaft without an O ring needs a yoke with no center vent. You can change the shaft
    type, but its probably easier to change the yoke. Bruce Roe
  9. buick64203

    buick64203 Just plum crazy Staff Member

    Im wondering if I could just tap the hole and thread an allen screw in there?
  10. DaWildcat

    DaWildcat Platinum Level Contributor

    If I remember right, mine was just a steel cup plug in the yoke - I hit it with a MIG; a minute-long job. If yours is the same, that's another alternative.

  11. Mopar

    Mopar Well-Known Member

    Wouldn't that throw off the balance of the drive shaft?
  12. DaWildcat

    DaWildcat Platinum Level Contributor

    The hole is at zero in the center of the yoke in front of the u-joint, so no worries.


  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"


    BUQUICK I'm your huckleberry.

    I had this same problem when I was poor college student so I just wiped off the yoke and filled the hole with silicone and it never leaked again. Not a good fix but I was looking for the easiest/quickest fix since I was working in the dorm parking lot.
    knucklebusted likes this.
  15. buick64203

    buick64203 Just plum crazy Staff Member

    Geez, I may have to splurge for a new U joint for this POS!:grin:
  16. TexasT

    TexasT Texas, where are you from

    Hey, a running driving pos is worth way more than a regular pos. Plus think of the fun you are having with it and not having to worry about hurting scratching or denting it. Priceless!
  17. Larry Mendoza Jr.

    Larry Mendoza Jr. New Member

    I hope someone can advice if pluging the weep hole does not affect any function of the car, i own a 1970 gs 455 and while changing mufflers and the car suspended off the floor when in idle i can see ATF fluid leaking from the weep hole, it leaks a lot less when idleing on the ground.
    Any advice.
    Thak you in advance
    Larry Jr.
  18. knucklebusted

    knucklebusted Well-Known Member

    I did the same thing back in mid 80s and it held until I swapped for an overdrive.
    BUQUICK likes this.
  19. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I believe his fix was swapping in a 4 speed..
  20. buick64203

    buick64203 Just plum crazy Staff Member

    LOL!! Yes it was. Definitely doesn't leak ATF anymore :D:D

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