8.2 To 8.5 Swap Finally

Discussion in 'Got gears?' started by 68Rivi_In_Cali, Mar 9, 2020.

  1. 68Rivi_In_Cali

    68Rivi_In_Cali Well-Known Member

    I finally tracked down an 8.5 out of a 72 skylark locally. LL B295 2 is stamped on it. It and the ring gear says it's a 2.73.

    I will be replacing the 8.2 in my 70. I currently have 2.56 open rear with 28 inch tall tires and a 4 speed m20.

    Its a highway cruiser and a Dog off the line.

    Hopefully the 8.5 will help me light the tires up and take off harder.

    I am going with the Yukon Duragrip 28 spline carrier and the Yukon 3.42 Gears.

    Will this Rebuild kit be all that is needed to replace the bearings? I have a shop that can rebuild it for $450 with me providing the parts.

    My plan was to remove the rear and install the 8.5 after it was built. I should be able to do this with jack stands and a regualar big 3 ton jack right? Any tips?

    I will also have the driveshaft shortened 1inch if I remember correctly.

    Can't wait to see how much of a difference it makes.

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  2. Brandon Cocola

    Brandon Cocola Well-Known Member

    I have the same thing going, 70 Skylark with 2.56 open and have a 71 GS350 rear picked out. My plan is to get it and when I put the 455 and th400 in I would do the rear swap then.
    68Rivi_In_Cali likes this.
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    When you have the 8.5 built, ask them to leave the axles out. That way, you can unbolt and pull the axles on your 8.2, then wire up the backing plates. Then remove the 8.2 and replace with the 8.5. Install your axles and bolt everything back together. The advantage here is you don't have to mess with hydraulics and emergency brake cables. I did this when I went with the same swap.

    Another tip, make absolutely sure you get the right axle seals for the 8.5. The correct seals are .490" thick. There are seals out there that are .460" thick or even thinner. If you are unfortunate enough to use them, you will have excessive axle end play. Just measure them before the bearing install. The numbers are 712146 and 2146 for the seals. The thickness is inconsistent so it pays to measure before. This is a well known issue and there are several threads about this.


    I would have another floor jack handy. Sometimes, to line up all the control arm bolt holes, you need to put that additional floor jack right under the pinion and move it up and down to get everything to line up.
    Last edited: Mar 9, 2020
    68Rivi_In_Cali likes this.
  4. 68Rivi_In_Cali

    68Rivi_In_Cali Well-Known Member

    Thanks Larry. That actually would make things easier. I do have new hardware/ wheel cylnders and shoes I was planning on installing but they are still in great shape. If I can get away with not having to do that, then I'm all for it. I should get an axle housing with a fill hole in it then.

    When bolting the axles back in, do I have to add some RTV or sealant to the splines?

    I am guessing its as simple as mounting the backing plates back on and then bolting the axles in.

    Good Call on the seals!

    I might as well order the complete kit and the extra axle seals to be safe.

    Looks like I can get them Locally as well

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    Last edited: Mar 9, 2020
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No RTV. Just bolt them in. I would actually measure the seals. Many are not boxed correctly. Doesn't matter what the catalog says if it doesn't match up to whats in the box. I thought the thickness was supposed to be .490. Maybe PM Monzaz and get the latest info before buying the seals.
    68Rivi_In_Cali likes this.
  6. Bigpig455

    Bigpig455 Fastest of the slow....

    x2 on the seals -I think the correct ones come from Timkin. Check with Monzas or Brian Trick but make sure you have the correct ones. The wrong ones cost me a tow, fluid, outer axle bearings and a weekend.
    68Rivi_In_Cali likes this.
  7. Redmanf1

    Redmanf1 Gold Level Contributor

    Good info^^^^
    68Rivi_In_Cali likes this.
  8. Bens99gtp

    Bens99gtp Well-Known Member

    I would also do it by hanging the brakes for the swap over.........just make very certain you dont get the axles swapped up, as they look very very similar they are not the same.........I forget which way it goes now.........but one set will slide into the other but be slightly sloppy and the other set will not even go into the other.

    I think the 8.2 will go into the 8.5 but not the 8.5 into the 8.2......but that could be backwards
    68Rivi_In_Cali likes this.

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