changing gears

Discussion in 'GM Powertrain' started by Burden33, Sep 25, 2009.

  1. Burden33

    Burden33 Epic Member 5+ Years 500 Posts

    right now im running a 2008 chevy sailverado crew cab with a 5.3L and gears i got 3.73 i got a 1.50" leveling mkit with 305/55/R20 toyos im looking to change the gears to my truck to a 4388 will this change on how highmy rpms are when at a steady speed and do it change on how much gas it is going to drink. this is trhe first time for me ever dealing with gears
  2. jbfireemt

    jbfireemt New Member

    this will for sure raise your highway rpm and reduce gas milage. rpm's by maybe 400ish on the highway, and gas milage i'm not sure, but it will drop. i have 4.10 gears in my truck and tow occasionally, but 4.88's are really deep for a truck without bigger tires, they may not give you the gain you are looking for. a shop is gonna charge huge money to make the switch, enough that you could probably do a cam swap. but i am speculating on your intentions. let me know if you have more questions. gears are not really a weekend warrior project, but it can be done if you take your time.
  3. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    4.56 & 4.88 are really for when you are gonna do a bigger lift and much bigger tires. Unless this is your plan to drastically lift your truck I wouldnt go that high, maybe a 4.10, if changing at all. What are your overall plans for your truck, and while they may be plans are they truely realistic to achieve and really be worth the investment of gears.
  4. Burden33

    Burden33 Epic Member 5+ Years 500 Posts

    i was looking at a 4" suspension ligft with 35" tires or keep it the way i got it and throwing performance under the hood maybe new cams exhaust nitrous system would the gers help me get down the trak faster in a race or will 4.10 do the trick
  5. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    4.10 are great choice, they wont give you a huge hit in MPG like the 4.56 or 4.88, they will help keep you in the power band. Before all the manufacturers got all up and up with fuel eceonomy, 4.10 were what was evalable for the IROC Camaro, I had a 84' 305 Berlinetta Camaro and it had 3.43 I think and after swapping in the IROC rear end it was a world of difference even for a 150hp carb 305.
  6. canislupis69

    canislupis69 Epic Member 5+ Years ROTM Winner 5000 Posts

    Unless you are going with 35's I would stick with your current gears or 4.10's at the most. I have 35 inch tires with a 7 1/2 inch lift and I went with 4.56's. It drives much better now; however, once you go bigger numerically than 4.10's on a NNBS Silverado your ABS warning light is going to come on and occasionally it will give you the annoying chime. Our trucks were not designed to go an larger than 4.10's. Currently their is no fix for this (other than putting electrical tape over your ABS lights.
  7. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    I have both 4.10s and 4.56s on two trucks with 35s. Two go from 3.73s to 4.56s is a jump in rpms and you will see a mpg drop. It depends on what your looking for. MPGs or pulling power. I think the 4.10s with 35s are a good compramise between MPGs and pulling power.
  8. Burden33

    Burden33 Epic Member 5+ Years 500 Posts

    ill be putting 35" tires with a 4 inch suspension lift and im going to run 4.10 gears and jurin a programmer and exhaust.
  9. dsfloyd

    dsfloyd Epic Member 5+ Years ROTM Winner 1000 Posts

    Superlift sells a fix for this. Its there truspeed abs recalibrator for gearing 4.56 and lower (numerically higher). there part number is 34000. They also sell a speed calibrator which i have and like. I do not have the abs calibrator cuz I only went 4.10s
  10. dsfloyd

    dsfloyd Epic Member 5+ Years ROTM Winner 1000 Posts

    I went 4.10s with 35s and like it because I do mostly highway driving (60 miles/day) and it kept the mileage the same since it dropped the rpms. If I did a lot more towing I would go 4.56. Still tows great just has to shift down more on hills.

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