'88 10 bolt 8.5" ring gear differential question

Discussion in 'Chevy C/K Truck Forum' started by The Tall Guy, Mar 15, 2013.

  1. The Tall Guy

    The Tall Guy New Member

    Hello, I am in the process of putting my differential back together. This is what I have done so far: I replaced the pinion bearings and races. I reinstalled the pinion gear and bearings and tightened the pinion nut to a preload of 19-20 in lbs. All seemed well and the pinion yolk turned smoothly. I inspected the carrier bearings and bearing caps and they still looked good so I decided to reuse them and the 2 spacers, one on each side. I intalled the carrier and tightened the bearing cap bolts to their specified torque. Now, the pinion yolk is so tight I can only turn it with a crescent wrench. What did I do wrong? Will it get better with gear oil in case and a break-in period to seat the new bearings and races and get everything back into line? This project has taken a couple of weeks to complete, so most of the oil has drained from the carrier and bearings. Or do I need to tear it down and start over again? Your help and expertise will be greatly appreciated.
  2. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    That doesn't sound right to me. When I have had a diff open (oil drained obviously), the R&P has always rotated freely.

    I have never rebuilt a differential or set up gears, so I'm mostly talking out of the side of mouth from hearsay and other forms of guesswork. I would guess that in installing the pinion gear, you got the pinion depth off (if that is possible, I know it is part of setting up the gears when installing new R&P), or you got the carrier shims installed on the wrong sides, or something else to throw off the R&P set up parameters.

    As I said, I have never set-up an R&P, so I can't speak to the nuts of bolts of doing it. I have a basic overall grasp of what is involved, but the devil is really in the details when it comes to this. I would guess that your next step is going to be carefully going through the art of setting up the R&P to make absolutely sure you are getting it set up right.
  3. AC`s94chevy

    AC`s94chevy New Member

    Hi Im new here didnt want to start a new thread but I have some questions about setting up a different rearend in my truck also.
    Currently I have 8.5 10 bolt open rearend with 3.08 gears.I recently bought a 95 with 3.42`s.Can I just swap the carrier assembly and pinion gear or do I have to replace the whole axle assembly?Thanks
  4. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts


    Assuming you have got your parts interchange research done correctly (including verifying that the recipient and donor axles have the same size/spline axleshafts), then it should be as "easy" as swapping R&P and carrier.

    Easy is in quotes because you will need to be able to set up the gears correctly (pinion depth, backlash, wear pattern, etc.) which is a fairly detailed process. Most people advise that it is not for the uninitiated. If this is your first time, I would at the least find someone who does know how to set up gears to coach me through it.
  5. AC`s94chevy

    AC`s94chevy New Member

    Thanks for your reply
    Both axles are 5 lug so the splines on them should both be the same.Im told that the only thing I may have to adjust by shimming the pinion gear depth.

    - - - Updated - - -

    Today Im going to be working on getting the carrier assembly out of the axle housing I just bought so wish me luck.I`ve removed a few of them so it shouldnt be that hard of a job.Im also in the same predictment as Mr Shorty I never setup gears before so I`ll be looking for more help along the way as I get into this project.
  6. AC`s94chevy

    AC`s94chevy New Member

    Ok guys I got the carrier and axles out yesterday.Went to remove the nut on the pinion gear so I had to take it to a shop that I have buddy that works there to loosen the nut with his impact.So now that the nuts is loose is there a locker thats holding the pinion in on the front or do I have to pound it out?Thanks
    Edit got it out just didnt have a big enough hammer.
    Last edited: Mar 22, 2013
  7. AC`s94chevy

    AC`s94chevy New Member

    Ok guys everything is out of the old axle and Im ready to do the swap.I have got pinion shims,pinion seal,new bearings and races for pinion,what else do I need other than a dial caliper?

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