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  1. #1

    Default Towing and recommend gear ratio w/35's

    So I recently picked up an 04 Silverado. 4x4 5.3L 9" lift 35" tires. Runs good but sluggish for acceleration and horrible gas mileage. I suspect stock gears still in which are 3.23's maybe or lower.

    Anyway I'm looking to buy 26' trailer. I feel I have low torque now and can't imagine towing. I plan on intake and tuner.

    What is a good gear setup.

  2. #2

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    Well, the first thing you need is a starting point, find out what you have now.

    Read post #4 in this thread and you should be able to find the info: http://www.gmtruckclub.com/forum/sho...e-used-anymore
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  3. #3
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    Enkeiavalanche's Avatar
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    That is going to be a big strain on everything.. Do you plan on towing alot? I'm not a gear export but I think one will chime in soon..
    08 Z71 Avalanche Mods to date: K&N CAI,Hellwig Swaybars and End Links, Corsa Sport Exhaust, Superchips Programer,IPCW LOF & 3rd brake light and tails, AMI Gas door,Show Hooks and Door locks, Enkei Wheels, with Pirelli tires, StreetScene Bowties, Grant Steering wheel,Muth signal mirrors,SSBC Big Brake kit,Huskyliner Mug gards,Floor mats and Hood shield, McGard Lug nuts and locks, Bedrug, Cervini's Ram Air hood,35watt HID Fog lights, Sylvania bulbs all around ZXE's Highs and Lows, WhiteNight Back up lights,Sirius and HD Radio, SnugTop sitting on deck now Got a Softopper on now,Tempress Boat Hatches.... New Bilstein shocks are on... New Mods coming soon..... X

  4. #4

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    well just for what i tow haul and play with timkin makes a great spring that mounts where your rear bump stop is at and it helps alot i haul 1 ton of wood pellets in the bed and then pull my wifes wrangler all the time i load everything in the bed of the truck all the time .. i have 1 gu6 (3:42 ) rear with the g80 so its gov lock i get really great gas mileage im not gonna beat anyone of the line but i can pull stuff just fine ..... also a cold air intake and new exhaust would not hurt at all
    Bowaddict13 ( Jason) 2005 5.3l GMC seirra 4x4 crew cab 1500, 77 chevy van 350, 87 chevy suburban 350, 94 gmc sonoma 4.3, 96 gmc sonoma hi rider 4.3, Two 95 chevy tahoes both 350s, one red one blue

  5. #5
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    I moved your thread to our towing section and changed your thread title to represent your topic. This will help in getting you more responses/opinions.

    Regarding your question, I'd recommend 4:56s if you are going to be towing occasionally or you may want to consider 4:88s if you are going to be pulling/towing a lot. I had 3:73s w/35s and my truck was a dog, especially going uphill, starting from traffic lights, or trying to pass someone on the freeway. I now have 4:56s and they are serving me well.

    This gear ratio chart should help....http://www.4x4offroads.com/gear-ratio-chart.html


    Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD

    SUSPENSION: Rancho 4" Suspension Lift; Rancho RS9000XL Shocks; Rancho Skid Plates; Rancho MyRide Wireless Shock Controller;
    TIRES:
    BFG All Terrain KO 315/70/17
    DRIVE TRAIN: 4.56 Gears; Detroit TrueTrac Differential; True Cool 40k Transmission Cooler
    PERFORMANCE: DiableSport Predator Tuner; Custom Tuned by Diablew; Magnaflow Exhaust; AFE Cold Air Intake
    ELECTRONICS: Kenwood DNX6180 Touchscreen; Subthump box w/10" Kicker; Driver Information Center (DIC); Rear View Camera
    ACCESSORIES: Westin Brush/Grill Gaurd; Westin Nerf Bars; Truxedo Tonneau; 20% Tint; Tow Mirrors w/Heat & Signals

  6. #6

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    Quote Originally Posted by mfleetwood View Post
    I moved your thread to our towing section and changed your thread title to represent your topic. This will help in getting you more responses/opinions.

    Regarding your question, I'd recommend 4:56s if you are going to be towing occasionally or you may want to consider 4:88s if you are going to be pulling/towing a lot. I had 3:73s w/35s and my truck was a dog, especially going uphill, starting from traffic lights, or trying to pass someone on the freeway. I now have 4:56s and they are serving me well.

    This gear ratio chart should help....http://www.4x4offroads.com/gear-ratio-chart.html
    I always tell people don't ask me for help and then argue with my answer so I won't do that because I genuinely need help. I just want to make sure you saw I have stock 3.23 or similar gears. There's no problem swapping from that to something like 4.56?

    I don't plan towing daily, weekly, or even monthly. I have a nice bumper set up. Its after market and supports 9600 pounds I believe.

    - - - Updated - - -

    OK I do have 3.73 gears.

    - - - Updated - - -

    I do have exhaust and I plan on cold air intake and a superchip

  7. #7
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    No worries...ask away. It's always better to question until you are comfortable with the responses and it gives you a chance to garner more information. It is also helpful to receive responses/opinions from others as we all have different experiences and/or knowledge base. I don't think you have 3:23s, as I couldn't even find a GM RPO code that aligns to it, but I'm not an expert so I didn't mention it before. I think the lowest I've seen people discuss here for the NNBS are 3:42s. Regardless though, 4:56s should not be a problem as they will fit in your differential (even if you have the smaller 10 bolt like I do). And if I remember correctly, 4:56s may be the highest you can go. Again, I am not an expert in this area, I'm just going by how I went through this same exercise with my truck and sharing with you my learnings.

    Check your glove box for the RPO codes and use this link to figure out which options your truck came with. http://www.rpocodes.com/GM-RPO-codes...GthroughM.html

  8. #8

    Default

    @dgreen816,
    Since you indicated you have a 5.3L, I'm guessing you have a 1500 (which implies a 10-bolt rear diff and a 4L60E tranny), as I'd expect a 2500HD to have a 6.0L in it...

    Speaking as someone who regeared from 3.73's to 4.56's on a 2004 5.3L 1500 4x4 with a 4-speed 4L60E tranny (running 34.3" tires), I can definitively tell you that 4.56's for 35's will get you very close to what your stock performance was with OEM tires and 3.73's. With my 34.3" tires I have a slight bias for power compared to the 3.73's with OEM tires ... which will be lessened for you with 35's but will still be present.

    You -might- be able to squeeze 4.88's in the diffs but with a 4-speed tranny you would hate those shorties on the highway. My sweet spot on the highway is 50-65mph. Higher than 65mph and my highway mileage falls; the faster (above 65) I go, the more it falls. 4.88's would have a slower sweet spot than the 4.56's, the range would be smaller, and they'd exhibit substantially worse highway mileage outside of that sweet spot -- however the low-end torque would be awesome. That said, I'd worry that 4.88's would be torquey enough to be of concern as it pertains to axle wrap conditions on our 1500 leaf springs and rear axles. If you add all of this up, I'm of the opinion that even if 4.88's will fit in the diffs they are ill-advised on a 1500. A 2500HD is a different story...

    It's good that you intend to get a tuner, as a tuner will be essential for telling the truck your new gear ratio. A custom tune to squeeze out a little more grunt is advised. However, if you do, indeed, have a 1500 then I hope the big-arse trailer you intend to buy is well under your GVWR after you account for the added weight of the tires/wheels, cab, passengers, other load ... and then also consider the already-reduced braking effectiveness you have that's caused by your large, heavy tires and compounded greatly by your (very high) lift -- unless, of course, you've done all appropriate brake system upgrades to compensate.

    I mention the brake system because it is important for safety ... and even more important if you're in mountainous regions where you'll brake a lot and have to slow/stop not only your truck but the load you're towing, too. (I'd expect brake axles on a 26 footer, but still, what if they fail or you have a bad brake controller connection, etc??) Heat and brake fade would be a serious issue ... and as it pertains to the brake system -- in case you're unaware, the higher you lift a truck the more work you make the front brakes do -- specifically because of the change in center of gravity you've introduced to that heavy weight above the front axles that we call an engine. Similarly, the higher you lift a truck the longer your brake lines get ... which reduces peddle feel unless you've replaced the rubber hoses with stainless steel lines to improve peddle feel. Also, the bigger the tires you have the fewer rotations they make across a given distance compared with OEM tires over the same distance -- meaning less opportunity for your brakes to do their jobs. To compensate you need larger rotors and pads and, ideally, more pistons in the calipers -OR- substantially better same-sized brake components with an acknowledgetment that braking distance is still increased (compared to OEM) but is a bit better than with OEM components.

    To put it all another, simpler way, I hope you plan to tow a very light but big boat ... or a super light but long trailer. If not you may not have enough truck for your intended use and perhaps you should consider upsizing in order to safely meet your upcoming towing needs. Check your GVWR and check the loaded vehicle and trailer weight against it. Also compare your tongue weight while at it, to be safe.

    Don't guess, estimate, or eyeball. Be sure -- as your safety and that of others on the road is at stake. No cash savings is worth a life or a limb -- of yours or another's. An accident in any vehicle can be life-changing -- and the risks are that much more likely and substantial where an overloaded vehicle is involved. @moogvo might have something to add, here, as it pertains to what can occur if you overload your vehicle and have an accident -- he's a first responder so he's got some knowledge/experience/insight that most of us lack.
    Last edited by SurrealOne; 01-04-2013 at 11:30 PM.

  9. #9

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    Quote Originally Posted by SurrealOne View Post
    @dgreen816,
    Since you indicated you have a 5.3L, I'm guessing you have a 1500 (which implies a 10-bolt rear diff and a 4L60E tranny), as I'd expect a 2500HD to have a 6.0L in it...

    Speaking as someone who regeared from 3.73's to 4.56's on a 2004 5.3L 1500 4x4 with a 4-speed 4L60E tranny (running 34.3" tires), I can definitively tell you that 4.56's for 35's will get you very close to what your stock performance was with OEM tires and 3.73's. With my 34.3" tires I have a slight bias for power compared to the 3.73's with OEM tires ... which will be lessened for you with 35's but will still be present.

    You -might- be able to squeeze 4.88's in the diffs but with a 4-speed tranny you would hate those shorties on the highway. My sweet spot on the highway is 50-65mph. Higher than 65mph and my highway mileage falls; the faster (above 65) I go, the more it falls. 4.88's would have a slower sweet spot than the 4.56's, the range would be smaller, and they'd exhibit substantially worse highway mileage outside of that sweet spot -- however the low-end torque would be awesome. That said, I'd worry that 4.88's would be torquey enough to be of concern as it pertains to axle wrap conditions on our 1500 leaf springs and rear axles. If you add all of this up, I'm of the opinion that even if 4.88's will fit in the diffs they are ill-advised on a 1500. A 2500HD is a different story...

    It's good that you intend to get a tuner, as a tuner will be essential for telling the truck your new gear ratio. A custom tune to squeeze out a little more grunt is advised. However, if you do, indeed, have a 1500 then I hope the big-arse trailer you intend to buy is well under your GVWR after you account for the added weight of the tires/wheels, cab, passengers, other load ... and then also consider the already-reduced braking effectiveness you have that's caused by your large, heavy tires and compounded greatly by your (very high) lift -- unless, of course, you've done all appropriate brake system upgrades to compensate.

    I mention the brake system because it is important for safety ... and even more important if you're in mountainous regions where you'll brake a lot and have to slow/stop not only your truck but the load you're towing, too. (I'd expect brake axles on a 26 footer, but still, what if they fail or you have a bad brake controller connection, etc??) Heat and brake fade would be a serious issue ... and as it pertains to the brake system -- in case you're unaware, the higher you lift a truck the more work you make the front brakes do -- specifically because of the change in center of gravity you've introduced to that heavy weight above the front axles that we call an engine. Similarly, the higher you lift a truck the longer your brake lines get ... which reduces peddle feel unless you've replaced the rubber hoses with stainless steel lines to improve peddle feel. Also, the bigger the tires you have the fewer rotations they make across a given distance compared with OEM tires over the same distance -- meaning less opportunity for your brakes to do their jobs. To compensate you need larger rotors and pads and, ideally, more pistons in the calipers -OR- substantially better same-sized brake components with an acknowledgetment that braking distance is still increased (compared to OEM) but is a bit better than with OEM components.

    To put it all another, simpler way, I hope you plan to tow a very light but big boat ... or a super light but long trailer. If not you may not have enough truck for your intended use and perhaps you should consider upsizing in order to safely meet your upcoming towing needs. Check your GVWR and check the loaded vehicle and trailer weight against it. Also compare your tongue weight while at it, to be safe.

    Don't guess, estimate, or eyeball. Be sure -- as your safety and that of others on the road is at stake. No cash savings is worth a life or a limb -- of yours or another's. An accident in any vehicle can be life-changing -- and the risks are that much more likely and substantial where an overloaded vehicle is involved. @moogvo might have something to add, here, as it pertains to what can occur if you overload your vehicle and have an accident -- he's a first responder so he's got some knowledge/experience/insight that most of us lack.
    there was great info in this post for you.

    So I will keep my answer short. Since you updated and said you have the 3.73's and explained your type of towing then I would agree with @mfleetwood and @SurrealOne in saying that 4.56 will be a great option for 35's. I put 4.10's in mine with 35's but at the time the towing was very infrequent and it was my daily driver. I was able to maintain my pre lift mileage but it is definately a bit sluggish when towing and climbing hills (and I have the 6.0 with 4l80e).
    David
    2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
    http://www.gmtruckclub.com/forum/sho...Silverado-2500
    1960 Land Rover Series II 88
    2001 Pontiac Sunfire
    2013 Toyota Avalon Limited (Wife's Car)
    NRA Life Member

  10. #10

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    Also keep in mind that if you upgrade the gears in the rear differential, you have to change the front diff to the same gear ratio. Failure to do so can cause binding when 4wd is engaged and you'll probably destroy a transfer case as a result.
    Christopher

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half



    There are 10 kinds of people, those who understand binary, and those who dont...

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