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1987 rear diff gear swap?

Discussion in 'Lifted & Offroad Suspension' started by socal77k5, Apr 30, 2010.

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  1. socal77k5

    socal77k5 New Member

    ok heres what i got going on, i have a 87 suburban, i bought it as a running project and thats exactly what i got, its lifted 4 inches, on 33 inch tires, and it drives like ****, runs well but drives horrible. it takes me a while to get up to 45 50 miles an hour. and wont go over 55 or so. im figuring i need a diff gear swap probably to 4:56? my question is how hard would this be to do myself? i know someone selling a gm 14 bolt 456 gears, how hard would it be for me to put this in my rear diff. i disconnected my front drive shaft because the guy who put on the lift didnt do anything to the shaft or trans so it doesnt reach. the front lift is horrible, 4 inch block (illegal) and theres only 2 leafs per side. the shock hoops cracked and broke off due to this **** lift. rear lift is fine. so anyone on here know how to swao gears maybe help me out with a step by step?
  2. Mean_Green_95

    Mean_Green_95 New Member 1000 Posts 100 Posts

    If you've never done gears before, pay a professional to do it. It's very easy to screw up the gears and blowing up the diff.
  3. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts 100 Posts

    Why not swap over the whole axle and alleviate the problem of trying to set-up the gears properly?
  4. socal77k5

    socal77k5 New Member

    thanks ill have to do that. maybe imight just drop the lift 2 inches, and throw on some smaller tires. ok so lift is ****, if i drop teh lift 2 inches would that take care of teh power problem?
  5. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts 100 Posts

    If you drop the tire size it might, depends on gear ratio though.
    With Suburbans its always best to keep tham as low as possible, their like big sails going down the road and any help in the profile department improves drag.
  6. socal77k5

    socal77k5 New Member

    yeah im trying to find out what the 1987 suburbans stock gear ratio is, cause im pretty sure the previous owner didnt change it when he thew on the lift, so i plan on swapping the 4 inch lift for a 2 inch lift and throwing on 31s or 30s to best fit teh gear ratio.
  7. vncj96

    vncj96 New Member 1000 Posts 100 Posts

    your stocks should be 3.73 or 4.10, but if your truck is struggling with only a four inch lift and 33s then i dont think that a gear change will help, this sounds like a bigger problem. Stock gears from that genereation should be handling your 33s just fine. i have 3.73 on my 99 and going up to a 33 mad almost no difference on the stock gears
  8. socal77k5

    socal77k5 New Member

    thats what i was thinking too, i am thinking its more along the line of the lift and the trans, i noticed today when i lifted teh truck on a hydrolic lift, and had the motor running, that the torque converter looks like it has pressure on it and causeing it to wobble, now if the guy did a shotty job on the lift could that put the trans at a bad angle and cause lack there of power?
  9. vncj96

    vncj96 New Member 1000 Posts 100 Posts

    It could be binding things up that is for sure.
  10. socal77k5

    socal77k5 New Member

    yeah i think thats whats going on, i think the guy did a horrible lift job. the torque converter looks like a football being thrown just wobbly as hell. if i go easy on the gas pedal it will shift perfectly, but if i step on it, it will bog and not shift until i let go of the gas pedal

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