Gear change S10

What would be the ramifications of changing the rear end gear in my 96 S10 2.2 automatic from 3:23 to 3:42?
I think this is the oval 7.5 rear end. At this point, i think i might
have a chipped gear on the pinion and have a chance to buy a gear set out of a 99 for reasonable. (not the whole rear end, just ring and pinion)
With a lower gear, what kind of mileage penalty should i expect? (I am getting 17/18 MPG in town now) How hard is it to change the spedo gear for speed correction?
I have seen things before that it is not an easy task to get the gears to mesh correctly. I take it its more than just dropping a gear set and pinion out and dropping another one in. How difficult is it to set the shims and the gear mesh point?
If this is a big issue, how old of S10 complete rear gear (or any other GM) will swap in? What years did they change the spline count on the axles? Would a F body rear work? I am not trying to beef it up or change the whole rear housing and all. I would like to just pull the differential and repair or replace it. This truck also has anti lock. Any difference in the rear ends? I did not notice any electrical connections out of it.
Bob
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Hi Bob,
Just a quick note - our 2002 2.2L Sonoma has 4.11 gearing. I cannot image how sluggish she would be with 3.23 gearing. Are you sure your 1996 came with 3.23 gears?
Dennis
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snipped-for-privacy@thruster.nailed.org wrote:

You won't notice the difference between a 3.23 and a 3.42. Both seem too low (numerically) for a 2.2L. To set the gears up takes some skill and a dial indicator. I would look for a used rear (complete) rather than mess with the gears if you haven't done this before.
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