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Gears...

Discussion in 'The Garage' started by pvfjr, Mar 7, 2005.

  1. pvfjr

    pvfjr 1/2 ton status

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    What might be found under a S10 blazer? We need to replace the rear end in a 89, and there's a 85 being parted out a ways away. I'm just wondering what I might run into.
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    IIRC, the two most common ratios in the 80's were 3.42 and 4.10.

    I remember looking for them for my buddy. His 2 door Blazer with 700R4 was 3.42, and IIRC, the 4.10's came under trucks with manual trannies.

    Gov-lock was what GM used as RPO G80 in these, and you will DEFINITELY want to try and remove the axles before purchase, as the pinion shaft lock "bolt" is very prone to be broken in these, and that means you can't pull the axles out if you need to.

    In our case, I pulled the brake backing plates off the axle (complete) after removing the axleshafts, so no dealing with the ebrake, unknown condition brake components, etc. Just left the brakes hanging and swapped the axle housing minus the brakes. Can't do that if the axleshafts won't come out.
     
  3. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    ive seen alot of 3.08s and 3.73s also. it really depends on what motor, auto or manual and if 4wd or 2wd.

    yes, ive seen quite a few of these bolts broke.
     
  4. pvfjr

    pvfjr 1/2 ton status

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    I'm not sure what bolt you're talking about, but we're planning as swapping the whole rear end as one assembly. I'm just hoping the one we're looking at will be the same, cause we have to get this fixed fairly quick. The guy with the donor blazer can't check it till Sat, so we'll see. It's an 85 4wd, I think with a 2.8. Ours is a 89 4wd with a 4.3. So what are the odds that it will match, or that it won't?
     
  5. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    that bolt holds the pinion shaft in that is needed to remove the axles.

    your 89 will most likely have 3.08, just about every 4.3 4x4 s10 has them. as for the 85, my guess is 3.42 or 3.73, you could get the RPO code in the consol and run them, its a G** code and look it up in the advanced previews forum.
     
  6. pvfjr

    pvfjr 1/2 ton status

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    So that's only if I need to remove the axle shafts from the housing right? I'll see if I can get a hold of that RPO code. Thanks.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Yes. Ever want to change wheel bearings, carrier, gears, posi, etc., that pin needs to come out. *Almost* impossible if it's broken. Has to be drilled out (special extra long drill bit, etc) depending on how badly its wedged in there.
     
  8. pvfjr

    pvfjr 1/2 ton status

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    Thanks for the info, I'll have to keep that in mind.

    Well, our '89 turned out to have a GU6 code, for 3.42's. Also a G80 for limited slip. Now we just have to make sure that it's still original, and find out what the donor has.
     
  9. R72K5

    R72K5 Banned

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    3.42 is all that ive ever seen under s-10s, ever

    so far

    4.10 i am pretty sure was only under the LUV's and toyotas, etc

    unless someone has some GM RPO codes available options sheets info specifically for s-10s back then that shows 4.10 was available with certain years drivetrains etc.

    id like to know theres 4.10's out there, cuz if so then im finding one for the 82 trans am, yes take welding to install under a third gen f body, but 4.10 wasnt available for any of them, just 3.73 and taller(ratio)

    good luck
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    I guarantee 4.10's were available. Looking for a G80 3.42 replacement 1988 S10 Blazer rear axle for my friend, I went through about 20 of these rear axles. 4.10's and 3.42's were ALL I was coming across, and the 4.10's that were still in trucks were backed with the manual trans.

    click 1986, recreation, then page 8 of the brochure.

    Kind of hard to read, looks like 2.73, 3.73 and 4.11.
     
  11. diesel4me

    diesel4me 1 ton status Premium Member

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    broken bolt a PITA

    My friend just showed me a new kit to drill out the broken bolt in the crosspin on GM diffs,it has a special long drill bit with left hand twist,you use it with a reversible drill in reverse--it comes with a spacer and a few other doo-dads--he says it worked good the first time he used it--not sure if it was Snap-On or Cornwell that he got it from..:confused:

    We used to have to use a punch(or an old crosspin) and a 3lb.hammer to dive the crosspins with broken bolts in them out of the carrier--more than once a chunk of the carrier broke off instead of the bolt shearing like we wanted it too,and a few trucks left the shop with a "good luck" and "good riddance" when that happenned!--but none of them came back looking to have another rear end installed,so I guess they lived..:blush:

    Its hard to drill out that bolt where its located,usually they arent in that tight though,its just the head of the bolt that snaps off,and the bolt is pretty hard steel and doesnt drill that easy,it tends to make the drill wander and cut into the carrier,making removal more difficult--but the left hand drill seems to do the trick,once it jams into the bolt,it usually will spin out with the drill...I hate doing rear axle bearings and backing plates on GM's due to the nightmare of the broken cross pin bolt syndrome--I spent nearly a whole day on those bolts,when the whole job should only take an hour or so....:frown1:
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah, from what I've seen usually the threaded part of the pin always comes out, if you could just grab that section left in there it would be an easier job.

    I tried hammering the pinion shaft out in a 7.5", and stopped when the carrier started to crack like you mention. Since it was under "warranty", I took it back, and had them pay to have the pin removed. That carrier is still in the truck, almost 200,000 miles on it now, and hasn't hurt it a bit.
     
  13. thor

    thor 1/2 ton status

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    R72K5, I just bought an 87 S-10 blazer and ran all the RPOs the other night to see what I had. I can provide the RPO # for 4.10s when I get home if your interested. Mine has 4.10s with a 2.8/T5..

    The G80 isn't a gov-loc in the 7.65 10 bolt. It can either be a thorsen, or an eaton clutch posi.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    What year did they go to the 7.625" rear?

    I know my friends 1988 G80 was most definitely a gov-lock, but I think they changed to 7.625" around that year as well, so kind of curious when they changed. Once I started getting into ABS years and what not, I didn't look at them.

    Odd because the cars DID use an actual clutch/spring type posi setup in the 7.5/7.625". (A/G/F-bodies)
     
  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Heat the carrier to break the locktite and I bet it'll come out.
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    Tim, the pin is threaded ONLY towards the head. The portion that breaks off is *unthreaded*, the threaded portion in every case I've experienced comes out no problem. The pin doesn't break because of the threads, the threads just happen to end where the pinion shaft starts. So you end up with the unthreaded portion of the pin left in the pinion shaft and other "half" of the carrier.
     
  17. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I'm aware of what the pin looks like, and youre right, i have seen them break that way.

    Sucks!! :mad:
     

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