Couple of drive-train/gearing/tire questions...

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by bigburb, Feb 26, 2009.

  1. bigburb

    bigburb Rockstar ROTM Winner 100 Posts

    Hey guys,

    I got a couple of questions here (I've got a 1990 suburban for those who didn't know):

    1.) What is stock gearing in this thing? It's a V1500 half-ton, with a 350 and a 700R4 tranny with 10-bolt axles. I'm guessing it's 3:73?? Is there a code on the axle of anything that I might be able to look at to tell?

    2.) I was thinking of doing the transfer case drop. It seems like a pretty straightforward process, but that's just from looking at it. Is there anything else I have to do except for put those spacers that are on top of the transfer case crossmember underneath it?

    3.) How would a stock setup like this like 35's? I really want 35's but I don't want a completely gutless gas guzzler. It's got 32's on it now and has no problem turning them. I don't think 35's (with stock gears) would be too hard, but I could be wrong...?

    4.) From what I've heard, 10-bolt axles should be fine with 35's as long as you don't have a ton of power and aren't a crazy skinny-pedal-to-the-floor off-road kind of guy? It's a stock 350 and I take it pretty easy off-road, so I probably shouldn't have any issues if I go with 35's, right?

    Sorry for the long questions, I'm kinda new to some of this stuff. I would really appreciate any help though!!
  2. 95CTburb19

    95CTburb19 Epic Member 5+ Years 1000 Posts

    I know on the 92-99 burbs if you look in the glove box there will be a series of letter/number combinations. These are RPO codes. I went out and wrote em down then went inside and looked em up on the web. If you type in GM RPO codes on google you will get plently of results. Some are paint codes and options and stuff but the important ones are listed as well.

    If you do 35's you will definitely see a drop in gas milage and you burb will probably be a little more sluggish than normal. I don't know a whole lot about the 10 bolt but if you don't have a limited slip/locker in the rear you will be less likely to blow it up.

    Also does that year run a solid front end or is it independent with CV axles? If it has CV axles you may break those if you beat on it too hard. I know in my 95 I snapped both of mine on 31's.

    Hope that was some help :great:
  3. bigburb

    bigburb Rockstar ROTM Winner 100 Posts

    Thanks, for the tip about the codes, I'll have to go check that out tomorrow.

    And I know I'll see a drop in gas mileage, I was just wondering if anybody had a good guess of how much. I already get only about 9 or 10, so how much worse could it get?? :lol:
    And it has a solid front end. They made the old 'burbs and K5's that way until '91.

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