Rearend Gear size? 96 c1500

Discussion in 'GMC Truck Forum' started by Wyley87, Jan 21, 2010.

  1. Wyley87

    Wyley87 Senior Member

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    ok i was looking at a post on a different forum where a guy was pulling a trailer and was wanting to change the gears out in the rear end. Anyway i have always wondered what size the gears were in my rear end. How do i find out?

    1996 GMC C1500 with 305 and 4L60-E tranny.
     
  2. 75K30

    75K30 Senior Member

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    Are you asking for the diameter of the ring gear or the ratio of the gear set?
     
  3. gpmorgan

    gpmorgan Auto Banned

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    id say you have a 308 ratio and an 81/2 ring gear. not 100% sure though.
     
  4. 1500cheyenne96

    1500cheyenne96 Senior Member

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    well if your asking for the ratio it's more than likely a 3.42 as most of the trucks for 88-98 that was the standard gear ratio for both 2wd and 4wd but some of the 2wd's 1/2 tons had 3.73's as well
     
  5. davbell22602

    davbell22602 Senior Member

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    I have 90 C2500 2WD 3/4 ton 8 lug and I have the 3.73 ratio.
     
  6. gpmorgan

    gpmorgan Auto Banned

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    i was going off of what my truck had. 81/2 ring 308 ratio.92 chevy 350 700r4. replaced them with 410 ratio and 8 1/2 ring gear.
     
  7. 1500cheyenne96

    1500cheyenne96 Senior Member

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    Really it had a 3.08 stock? wow i've never heard of that for those trucks i know it was pretty common on the 73-87 models but i didn't know that any 88-98's had a 3.08
     
  8. gpmorgan

    gpmorgan Auto Banned

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    yes 308 22mpg highway. but now with engine change and ratio change it gets 10 mpg:no::(
     
  9. 1500cheyenne96

    1500cheyenne96 Senior Member

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    yeah but at least it'll get up and go there quicker:)
     
  10. cajun cruiser

    cajun cruiser Senior Member

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    just jack up the rear end and mark your tires and driveshaft, turn both tires at same speed one rotation while someone else counts the rotations of the drive shaft and thats how to get the ratio, or if you have the codes in the glove box you can look that up
     

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