U-joint with different bearing sizes ??

Discussion in 'GM Powertrain' started by arby, Mar 14, 2014.

  1. arby

    arby Member

    My '97 K1500 extra cab (bought new) has a 1-piece drive shaft from the t-case to the diff. The rear U-joint failed and I discovered it has two different size bearing cups? The diff yoke is for 1-1/8" cups and the shaft yoke has 1-1/16" bores. My local parts store didn't list a 2-size u-joint. Is this a standard GM trick or is my truck a special case? Any reason I couldn't just bore out the shaft to accept 1-1/8" cups? The inside snap rings seem to line up ok - the cups are just too big. Thanks for any wisdom on this.

    - - - Updated - - -

    Ok, I guess I found an answer. The drive shaft was just made that way. The shaft has a fiberglass tube with aluminum ends. I found this listing on eBay - "Firebird Conversion U-Joint 10 12 bolt 1 1/16" Caps x 1 1/8" Caps". There are several other 2-size combination and conversion u-joints listed as well. May ream out the shaft anyway.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    In my opinion, reaming the shaft would be a major mistake. Like you said those end caps are aluminum. If GM thought that they could handle the same size caps as the rear pinion yoke then they would have put them in. reaming them out will make the ears of the end yokes on the aluminum cap thinner. I would fear that you might go from a low traction situation, like snow, to dry pavement and crack the ear off that you just reamed. My 1995 has the same setup as yours, I Just bought the right joints when I changed mine. The only issue I have had with mine is that the silicon that my end caps were pulling out of my fiberglass tube.

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