Gear swap and your opinions.

Discussion in 'Engine & Drivetrain' started by Bigkevschopshop, Aug 25, 2019.

  1. Bigkevschopshop

    Bigkevschopshop Full Access Member

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    I have been looking at gear swaps. Test drove a 3.08 vs 3.42 Tahoe and cant tell much difference. My burb has 3.08 gears. At 80+ on fwy it’s great. But accelerating from 50 to 70 you almost must hit the downshift. So I have thought about a full axle swap for $ factor should be cheaper. Maybe a z71 rear with 3.73 or just biting the bullet and throwing new gears in the current one. I know the swap in current axle will take more money and time yet there is nothing wrong w the axle in there now. So I ask. Those who have swapped what did you find the drivability to be like afterward and towing? Bang for the buck? Is the difference to 3.73 barely enough to be noticed and would you just throw money at some more Hp? The xl/burb platform is some extra weight for sure. But dang it drives good. And honestly can’t fully justify the extra 15k to upgrade to a Denali for the 6.2 right now since mine is paid off.
     
  2. gooffeyguy

    gooffeyguy Full Access Member

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    Don't forget that you will have to have a tune or use an off the shelf tuning device to set the new gear size so the speedo is correct and the trans shifts correctly

    2001 Yukon SLT
    2012 Yukon Denali XL
    2011 Yukon Denali RIP 5/20/18
     
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  3. R3cord303

    R3cord303 Posse In Effect

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    Absolutely do the gear swap. 3.73s feels perfect in my 2007. My grandfather has 3.23 or 3.55 years in his Ram, which also has a procharger running about 5 pounds of boost and that thing is a pig.
     
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  4. gooffeyguy

    gooffeyguy Full Access Member

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    I have 3.73s in the 2001 and it's quite peppy

    What year is your Burb? Early ones had the 4 speed trans.

    My Denali only has 3.42s, but it's a 6 speed trans (verses 4) and the motor has more power to begin with.

    2001 Yukon SLT
    2012 Yukon Denali XL
    2011 Yukon Denali RIP 5/20/18
     
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  5. Bigkevschopshop

    Bigkevschopshop Full Access Member

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    Mines the 5.3 with a 6 speed. I know the 6 has a good first gear etc. drives a lot in mid throttle like my 4.8 Tahoe I had. From a roll at 35 mph the 5.3 eats nice. Off line doggg. Seems the 3.73 is a good all around choice. Tow with yours much?.
     
  6. gooffeyguy

    gooffeyguy Full Access Member

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    I used to. I haven't in a while.
    I have an 18' tandem axle car trailer that weighs between 1200-1500lbs and used to haul my 5.0 mustang that weighs 3200lbs to different events.

    It hauled it fine and easily at highway speeds (65-75). I could definitely tell it was back there though. I do have a Prodigy brake controller that really helps in stopping.
     
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  7. Bigkevschopshop

    Bigkevschopshop Full Access Member

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    Yeah the prodigy is a nice unit for sure.

    Have an 18’ car hauler also normally have 3-5k on it when I tow. From what y’all say it seems the 3.73 is deft the go to gear to fix this beasts lack of ass. Haha.
     
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  8. thompsoj22

    thompsoj22 Supporting Member

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    Our 03 tahoe 4.8 3.42 was an absolute "sloth" when climbing anything. It was so dependable and we loved the space inside on roadtrips. We towed a approx 4k lb travel trailer and the engine was basically at 3,500 rpm constantly just to keep a consistant speed even on the flats. We allmost didnt make it up the grade once going to mammoth lakes out of bishop because i let the rpm drop below 3,500 in low 1! had we not been close to the top someone else would have had to drag the trailer the remaining 1/8 mile to crest the top. So i went to the salvage yard and bought a 3.73 brake to brake for $375 and installed it, it made an approx 500 rpm difference cruising at 60 and did keep the engine a bit more in the power but i gave up as "under powered is under powered" it climbed slightly better but did not add any torque so it was the same issue. traded it in on the 08 denali 6.2 and have been happy ever after. My opinion is your chasing your tail around the tree trying to gain more power/torque from the same displacement. cams/superchargers/turbo's are fun and work but at what cost to driveability/reliability. No disrespect to those who are forced induction! You will be happier with a bigger engine/trans."edit" Just read your post again, you are "paid off" and it is the 5.3 so you may have better results with gearing as you have an extra 30 lbs tq over the 4.8, Option #2 is to buy a lighter more aerodynamic trailer as your biggest challenge is while towing? Car payments suck!
     
    Last edited: Sep 13, 2019
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  9. avalonandl

    avalonandl Full Access Member

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    Is your Sub a 4wd? that means changing both axles,,,,
     
  10. swathdiver

    swathdiver Full Access Member

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    You get great gas mileage if I remember right. I'm happy to see 18 mpg @ 70 mph with my 3.42 gears. Those 6.0 2500s get 15 mpg with 3.73 gears.
     
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