T100 Driveshaft alignment

Discussion in 'General Tech' started by Bryan Plunkett, Mar 13, 2018.

  1. Bryan Plunkett

    Bryan Plunkett

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    Had this posted in my build thread but didn't get any feedback. Hopefully I can get some input from those of you with some experience in this thing.

    Background: I swapped a Mercedes diesel into my 94 T100 (link in my sig). the transmission moved backwards 5" and up 1" to fit everything. I replicated the tipped back angle of 3.4° for the transmission. My rear driveshaft is a two piece as shown below. The piece after the center support bearing remained unchanged, and the piece between the center support and the transmission was shortened 5" (and balanced). My u joint angle (12.5° - 3.4°, ~9°) out of the transmission is now *I believe* causing me a vibration in the 20-30mph range, noticed on acceleration. Truck did not have this vibration prior to the swap, and all of the u joint condition appear in good condition.

    I believe the correct plan of action is to raise the center support bearing (by way of cutting the cross member and shifting it up what I would guess to be 1", and then rewelding). Before I start that fun job...I was hoping to get some confirmation from those of you who have done something like this before.

    Feedback/any options are welcome (although I'd prefer not to buy a brand new single piece driveshaft if I can make the current parts work).

    ref.JPG

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  2. Bryan Plunkett

    Bryan Plunkett

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    bump

    ...man...no feedback...anyone?
     
  3. tominboise

    tominboise

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    That's a short (relatively) shaft and a lot of complication. I personally would remove and replace with a new single shaft. However, maybe there would be interference issues with the cross member when the rear suspension is compressed. I will add that in my experience on two shaft arrangements like that, it is good to have a little deliberate misalignment, rather than as straight as possible. Also, It's normally best practice to have the spline joint (the female) pointing down rather then up (opposite of your arrangement), to allow for any water ingress to drain out.
     
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