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How to "break in" new gears

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by '73 K5, Apr 13, 2000.

  1. '73 K5

    '73 K5 1/2 ton status

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    How to \"break in\" new gears

    I'm getting new ring and pinions installed as I type this. The stuff I got with the set-up kit said to drive it real easy for the first 50 miles, no towing for 500 and then to change the lube after the first 500 or so. No problem. Question is, how do I break in the front gears? Since I want them broken in before I take it offroad, should I lock the hubs and drive around for a while like that or should I leave the hubs "free" and put the transfer case in 4 wheel drive? Both options will turn the gears right??? I know tons of you guys have swapped gears, what did you do?

    '73 K5
    Chevy good...Ford bad
     
  2. BIGJ

    BIGJ 1/2 ton status Author

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    Re: How to \"break in\" new gears

    The best thing to do would be to find a dirt road to use. My instructions said to drive for 10 miles then let the gears cool. Then do the ten mile thing again and let em cool. The dirt is more forgiving than pavement and I wanted to avoid driveline bind as much as possible considering how long I had to drive. If that is not an option then I say lock the hubs in but not the t-case. It shouldn't bind if you do it that way. I personally like the dirt road thing b/c it gave me an excuse to get out of the city for a while. Damn traffic is a pain in the a#$ some times.

    BIGJ
     
  3. ggallin13

    ggallin13 1/2 ton status

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    Re: How to \"break in\" new gears

    How much is did your new r&p's cost? What tires do you run, and which ratio did you go with?
     
  4. '73 K5

    '73 K5 1/2 ton status

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    Re: How to \"break in\" new gears

    Lets see. Here goes
    R & P front: 170
    R & P rear: 160
    Both install kits: 180
    Eaton LSD with spring upgrade: 450
    Moser axles: 225
    New carrier for front: 90
    ARP stud kit for rear bearings: 20
    T/A Performance Diff Cover rear: 160

    It has on the wimpy 235/75 tires now, but I wanted to swap the gears before I did the lift and new tires. I'm 99% sure I'll be buying 33x12.50 Swamper radials in the next few weeks. Even if they aren't the Swampers I decide on, I've got to go with 33's.

    And the gears are (technically) 4.09 front and 4.11 rear.

    '73 K5
    Chevy good...Ford bad
     
  5. shaggyk5

    shaggyk5 1/2 ton status

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    Re: How to \"break in\" new gears

    ummm.....shouldnt you have the same ratio front and rear?

    shaggyk5

    aint nuthin in the world like a heavy chevy!!
     
  6. K5Junkie

    K5Junkie 1/2 ton status

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    Re: How to \"break in\" new gears

    i would think you should run the same gears front and rear.
     
  7. '73 K5

    '73 K5 1/2 ton status

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    Re: How to \"break in\" new gears

    Duuuuuuuuuuuuuudes. Those ARE the same gears. 4.09, 4.10, 4.11 gears are so close to being the same thing, gear places don't usually seperate them. What do you think I'm smoking crack? Nope. Dana/Spicer makes only 4.09 gears for the Dana 44, not 4.10 or 4.11. And U.S. Gear only makes a 4.11 gearset for a 4 series carrier for a 12 bolt truck axle. I probably could have found someone that made 4.10 or 4.09 for the rear, but I wanted U.S. Gear and I didn't need to. Think about it. When do you use 4 wheel drive? When there is copious amounts of slippage between the tires right? Mud...sand...dirt...etc. That way the tiny difference in gears won't matter anyway. Even if I did have exactly the same ratio in both axles it still wouldn't be perfect enough to drive in a straight line on pavement. The tires are never exactly the same size and the rims and other stuff like slop in the driveline. Thats why there's a differential inside the NP203 to make up for those problems since its used on pavement.
    A lot of people do the same thing just because the gears sets won't match perfectly. Sorry for the confusion. Next time I'll keep it simple and just say I have 4.10 gears.

    '73 K5
    Chevy good...Ford bad
     
  8. Blazer79

    Blazer79 1/2 ton status

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    Re: How to \"break in\" new gears

    As a matter of fact, I read somewhere that some serious mud competitors run a numerically lower gear in the front than in the rear. That makes the front wheels turn faster, which helps them steer much better. I was surprised at this when I found out, but it does make sense.

    <font color=black>//////
    What the heck!...Drive it like gas is $0.50/gal!!!
    </font color=black>[​IMG]
     
  9. '73 K5

    '73 K5 1/2 ton status

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    Re: How to \"break in\" new gears

    Right on! I've heard it both ways. Like you say and I've also heard of guys running higher gears up front so the front tires turn slower so they don't dig in as much and bury the nose of the truck. The rearend pushes the truck, but the front can still steer a little bit.

    '73 K5
    Chevy good...Ford bad
     
  10. KP3100

    KP3100 Registered Member

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    Re: How to \"break in\" new gears

    Beat the [censored] out of them, get them ready for what is to come

    1990 and bad ass!!!
     

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