4X4 problems

Discussion in 'General Chevy & GM Tech Questions' started by osgprometheus, May 7, 2012.

  1. osgprometheus

    osgprometheus Rockstar 100 Posts

    I have an 89 chev k1500, 4X4, 5.7 auto. I just picked up this project. When I put it in 4wd, and drive foward a bit, the tires turn in. Mostly the right front. it puts the front end in a bind. I have to back up, and get it out of 4WD. Put it back in 2wd, and it drives great down the road.

    I've never dealt with this before. Do you think the front and rear has different gear ratios? How can I find out what they are?
  2. MrShorty

    MrShorty Epic Member 5+ Years 1000 Posts

    That is certainly one possibility. Since this would mean that someone has done something to either axle (rebuild or replace), the RPO sticker would not be reliable. I don't know that I'd even trust a sticker stamp on the axles. IMO, the best way at this point to check the gear ratio of each axle would be to actually 'count' it.

    Jack up both wheels on the axle.
    Rotate the tires through one complete rotation, while counting the number of times the driveshaft rotates. This might be easier with a helper. Gear ratio=number of rotations of input (driveshaft)/number of rotations of output (tires).

    Open diffs, worn out limited slips, and Gov-locks can allow one tire to rotate faster than the other. In order for the measurement to be accurate, both tires have to both go through one complete rotation. Sometimes I've left one wheel on the ground so it can't rotate. With one wheel in the air, that wheel will go through two rotations for every rotation of the carrier, which introduces a factor of 2 to the gear ratio calculation.

    Not difficult and shouldn't take very long to do.

    Alternatively, especially if you are going to open the diffs up anway, you can count the number of teeth on the ring gear and on the pinion gear. Gear ratio = teeth on ring gear/teeth on pinion gear.
  3. osgprometheus

    osgprometheus Rockstar 100 Posts

    Cool man. Thanks for the info. The guy said he did get it rebuilt. I plan on adoing the SAC on the front anyways, but just screws with me now. lol
  4. kw70chevy

    kw70chevy Member

    i know the older 4x4s have numbers stamped on the ring gear. take the smaller number and divide into the bigger number and it will give you your gear ratio.

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