1. C Body Bob

    C Body Bob Old Man with a Hat FCBO Gold Member

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    While looking though my stash of 8 3/4 center sections. I only had 1 Sure Grip unit. There was no tag so I counted the ring gear & pinion gear teeth. I came up with a 3.08 gear. It’s a 489 case. Did they offer a 3.08 Sure Grip ? Never heard that ratio before.
     
  2. 70bigblockdodge

    70bigblockdodge Old Man with a Hat FCBO Gold Member

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    2.94 -3.23
    Count again.
     
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  3. C Body Bob

    C Body Bob Old Man with a Hat FCBO Gold Member

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    Ok that’s what I though. A math error. So did they offer a 2.94 Sure Grip ?
     
  4. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

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    Yes, I have 2 of them being rebuilt now.
    It’s stamped right on the edge of the ring gear exactly what it is.
     
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  5. Snotty

    Snotty Senior Member FCBO Gold Member

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    That's what I was going to say.
    IMG_0005.JPG
     
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  6. CBODY67

    CBODY67 Senior Member

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    For reference, on GM OEM gears, the tooth count of the package is on the edge of the ring gear, in a "heavy stamp" (i.e., 39T-10T), so you still have to do the match.

    Thanks for that picture!

    CBODY67
     
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  7. C Body Bob

    C Body Bob Old Man with a Hat FCBO Gold Member

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    Yea I looked & had a friend double check. We didn’t see anything. I have a 3.55 also & it’s stamped. May have been a service part. IDK.
     
  8. BIGBARNEYCARS

    BIGBARNEYCARS Senior Member FCBO Gold Member

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    I bought a 296 open from Murray Park 'cuz I waz looking for a better road gear for the Batwagon.(Keep the Rs down) Drove down to Tiffin, Met him at hiz day job while he waz still gainfully employed and he dropped it in the trunk of my Beater. When I looked at the ring gear it waz stamped 307 or 308 I can't remember? and I questioned it. He said this one came out of an Imperial and it's so close to the 296 your Beast will never know the difference. We both laughed, I payed him shook handz and both said we'll see yeah in July, laughed again and I left. That waz an open 307-308 BTW but for those who never saw that Beast live It tipped the scale @ 5800lbs with me in it and ah full tank the way I put it together. Two black marks when it had the 323 sure grip, single black Mark with the 308. 8 MPG either way but the Rs were done just ah tad, lol. Jer
     
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  9. C Body Bob

    C Body Bob Old Man with a Hat FCBO Gold Member

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    Hum, well I’ll be darn. I’m pretty sure I counted the teeth correctly. I always mark 1 & count 3 times. I wrote to numbers for both the ring & pinion gears down just can’t find it. That’s interesting info Jer. Thanks for that. I just never heard of a 3.08 myself
     
  10. furious70

    furious70 Active Member

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    Depending on the year and casting there are different numbers stamped into the gear, some are date codes, part numbers. Would love to see a photo of an actual gear stamped 3.08... That didn't come from a first gen Cummins truck with the 727 (not an 8 3/4)
     
  11. BIGBARNEYCARS

    BIGBARNEYCARS Senior Member FCBO Gold Member

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    Murrary and wife Mindy will be in their normal swap spotz just in from Gate #7 for the Carlisle Show. We've been friendz for almost 40 yearz. Stop by and ask him about that 308 rear gear, I think he'll remember. Jer
     
  12. fury fan

    fury fan Senior Member

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    There were some weird ratios for the 8-3/4 early in its life, IIRC there were some gearsets available in the 300s that went up to 6.17.