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I got a BAD problem with my rear diff and neet help PLEASE :)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Kia, Aug 7, 2003.

  1. Kia

    Kia 1/2 ton status

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    Hi all,

    I have an 1989 K5 (K1500) blazer and the rear diff was making some noise so I took the cover off and found that the main gear (sorry I'm not sure on the exact name of these things /forums/images/graemlins/frown.gif ) has some chiped teeth!!!

    I have called round and I have found a place over here in the UK that might be able to help but the guy was asking for the numbers in the case etc... what he wanted to know was the gearing and also said that there should be some numbers on/in the case but I can;t find them /forums/images/graemlins/frown.gif

    If anyone out ther can help me out with the right place to look for these numbers I would REALLY appretiate it /forums/images/graemlins/smile.gif

    Below are two photos that I took of the diff, you might just see the missing teeth on them.

    PS would it be a BAD thing if I left it like this for a while? I know it's best to change it but just wondering.

    Cheers guys and gals /forums/images/graemlins/smile.gif

    Kia.

    [​IMG]

    [​IMG]

    /forums/images/graemlins/k5.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/ears.gif
     
  2. Fry

    Fry 1/2 ton status

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    the numbers hes looking for would be on what you called the main gear just lift your truck up and take it out of gear and rotate your wheels till you see it. BTW its called the ring gear. And it would be bad to drive around like that my buddy had one lock up on the highway, not good. good time to regear your diffs. Good luck.
     
  3. Kia

    Kia 1/2 ton status

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    Thanks for that /forums/images/graemlins/smile.gif

    I had a look about 5 mins ago but the only numbers on that gear is "GM 3" nothing else /forums/images/graemlins/frown.gif
     
  4. Fry

    Fry 1/2 ton status

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    to find you gear ratio count the number of teeth on the ring vs the pinion (the one that drives the ring). Should be something like 3:08 or 3:73 when broken down. I think there are ID numbers on the axle tube but am not 100% sure.
     
  5. Kia

    Kia 1/2 ton status

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    The problem I have is that the truck isn't off the ground (gonna have to do it tomorrow I think if I can)

    does this help in any way...

    [​IMG]

    PS does anyone out there have a blown up diagram for the rear dif for a 89 K5 (K1500) blazer? I have just ordered the shop manual for it but it's gonna be a while till it comes over from the US /forums/images/graemlins/frown.gif

    Cheers /forums/images/graemlins/smile.gif
     
  6. Blazer1970

    Blazer1970 1/2 ton status

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    Yup, GU2 on that list indicates 2.73:1 gears. I could tell by looking at your pinion (huge), that those are really high gears.
     
  7. Z3PR

    Z3PR Banned

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    I guess this would be a good time to think about doing a axle swap. I have no idea how hard it would be to find a K20 or even a K30 in a wrecking yard there in England, but if you could, that's the route I'd deffently go. I don't know what the laws are regaurding lifted trucks with big tires over there either, but this would be a good excuse for axles that can handle the monster tires if you have any plans for them in the future. /forums/images/graemlins/thumb.gif
     
  8. Kia

    Kia 1/2 ton status

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    I want to try to keep it stock and I don;t off road so I'm guessing it wouldn;t be worth it for me... but thanks for the advice.

    Saying that I do want to lift it by 4" and put 33s on it /forums/images/graemlins/smile.gif
     
  9. 87BrnRsd

    87BrnRsd 1/2 ton status

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    Ouch! /forums/images/graemlins/ignore.gif Not good at all. At least now you have an excuse for a 14ff. /forums/images/graemlins/thumb.gif /forums/images/graemlins/eek.gif /forums/images/graemlins/rotfl.gif
    -Harrison
     
  10. Muddytazz

    Muddytazz 1 ton status

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    [ QUOTE ]
    Saying that I do want to lift it by 4" and put 33s on it /forums/images/graemlins/smile.gif

    [/ QUOTE ]
    If your going this route, i would at least think about 3.73's at the least, 4.10's would be better. I am currently running 33's on 4" and 3.08 gears and its a huge slug....takes 10 miles to get up to speed.
     
  11. wrathORC

    wrathORC 1/2 ton status

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    Between the thin ring gear, the monster pinion gear, and your RPO codes you definitely have 2.73s. AKA airplane gears.

    Now would be an excellent time to start thinking about an axle swap or different gear ratio. 2.73s are even too tall for 235x75r15 tires. I think 3.08s would be about right for 235s.

    I used to have 2.73s. I now have 3.42s. I can run overdrive at 60mph to 80mph with 33" rubber and 4" lift. Before, I couldn't run overdrive at all with just the 33" rubber. It was iffy even with 235x75r15s.

    I get almost 16mpg with the 3.42s on the highway. With the 2.73s I never broke 12mpg.

    Just clean out the case real well (you'll have to pull the carrier to clean out the carrier bearings) and the pinion bearings with some brake cleaner. You can run it but be easy on it.
     

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