'99 1500 towing questions

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by Weekend Warrior, Jul 11, 2009.

  1. Weekend Warrior

    Weekend Warrior New Member

    Hello all,

    First time poster.I have some specific towing questions I hope you might be able to help with.

    my truck- 99 z71 1500 ext 4x4 5.3 auto with the tow pkg and 373 10 bolt rear end 6" lift with 35's

    I am wanting to tow a 1/2 ton towable toy hauler of 21' to 23' with a dry wts ranging 4700 to 5400lbs, hitch wt range 500 to 750lbs and a gvwr 7500 to 9000 depending on model etc.

    User manual rates my truck at 7500 and depending what list you read it goes to 8200 lbs towing.

    1st question- Gear ratio: I was planning on getting some high quality limited slip gear installed to get back my ratio due to larger tires and towing needs. The 2 shops I have talked to said 4:56 but another person said that sounded a bit much for regular driving and towing. Comments?

    2nd - On paper it appears that my rig is perfectly capable of towing todays lighter weight toy haulers, So long as I am careful about my weights - especially when going fully self contained. However, one shop person whom I spoke with about the gear swap said that my truck really wouldn't be able to handle the load. Primarily due to the weakness of the 10 bolt rear end. He also said that I would defibately need the air assist springs, heavt duty tranny cooler, and even with all that it would be weak. Comments?

    Basically, I had hoped to get a toy hauler now while its a buyers market, and get a newer 3/4 ton in a couple of years. But the comments from the installer have me scared. I dont have the money to drop 4k into my truck just to struggle pulling a little trailer and then upgrade the truck. If I could just buy both I wouldn't be here hehe. So any comments would be great.

  2. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    My concerns would be more towards stopping power rather that pulling power. Those 1/2 ton brakes are already working overtime when paired up with the 35 inch tires. Toss an extra 4 or 5 thousand pound load behind that and you are inviting trouble. The torque load on the driveline is increased with bigger wheels/tires. Consider going with as small a trailer as possible rather than the biggest you can get away with.

  3. Jimmiee

    Jimmiee Epic Member 5+ Years 1000 Posts

    X2 on the brakes. I would look for a trailer with electric brakes. The 4.56 gears are OK with 35" tires. Here's a calculator link. Click
  4. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    I really think your pushing it. You would be pushing it without the lift and big tires, IMO. And what the trailer salesman describes as "half ton towable" should be illegal. They want to make a sale, the bigger the better. You could pull in with a dakota and leave with a 32 footer hooked to the back.

    Something to consider with toy haulers, is that they have very high tongue weights when empty. This is so when you load your quads in you don't pick the rearend of your truck off the ground. That heavy tongue weight is going to give you some squirrelly handling in a stock truck, never mind a lifted truck. Heavy tongue weight, big tires, and low gears in a ten bolt, you're asking for trouble. And the 4L60e doesn't have the best record either.

    I would be looking for a 2500 truthfully. Take the money you spend on gear/locker upgrades, the biggest brakes you can find, big tranny cooler, more frequent repairs, etc. and put that money with your truck for a nice used 2500.
  5. Weekend Warrior

    Weekend Warrior New Member

    Thanks for the good information.

    As for the trailer I want to pull the 23' is rated 4575lb with 735lb hitch weight, and the 21' i am looking at is less yet. I realize this is dry weight so going self contained will be higher. But in reality I won't be doing much of that, and I only have one quad. My guess is that I will be arond 6k on average.

    I know I need a new rig, and want one too, but getting both is out of the question unless I win a lottery. I was thinking that getting a trailer now and being really conscious of my load weights, I would be able to get by for a couple years or less before I upgrade the truck when other bills get paid off. My concern is that this isn't possible w/o a whole bunch of upgrades to my truck. My truck has the tranny cooler so I was hoping I would only need the gear swap and maybe helper springs at the most.

    Please keep the advice coming.
  6. 2COR517

    2COR517 Epic Member 5+ Years 1000 Posts

    Well, you could look for a 14 bolt to swap in the rear. They can be found in six lug varieties, but are rare. You'd be better off with the eight lug anyway; bigger brakes, bearings, shafts. Finding 4.10s would be easy, I don't know about 4.56. You would have to buy two new rims. Then just change your front axle to match. Get some really nice brakes for the front. Something else that may help your tranny is a programmer. I don't know much about them, but some advertise boosting the line pressures giving you better holding power on the clutches. And locking the TC sooner would drastically reduce heat buildup. Definitely want the biggest cooler you can find, shift kit, and synthetic fluid.

    The only problem with doing this work is that you are not going to get much of your money back when you sell/trade.

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