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Towing and recommend gear ratio w/35's

Discussion in 'Towing & Trailer Tech' started by dgreen816, Jan 4, 2013.

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  1. dgreen816

    dgreen816 New Member

    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. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

  3. Enkeiavalanche

    Enkeiavalanche Rockstar 4 Years ROTM Winner 5000 Posts

    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..
  4. bowaddict13

    bowaddict13 Member

    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
  5. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    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
    1 person likes this.
  6. dgreen816

    dgreen816 New Member

    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. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    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/gmrpocodesGthroughM.html
  8. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    @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: Jan 4, 2013
  9. dsfloyd

    dsfloyd Epic Member 5+ Years ROTM Winner Gold Member 1000 Posts

    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 [MENTION=37237]mfleetwood[/MENTION] and [MENTION=50075]SurrealOne[/MENTION] 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).
  10. Crawdaddy

    Crawdaddy Thread Killer Extraordinaire Staff Member 5+ Years 1000 Posts Platinum Contributor

    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.
    1 person likes this.

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