Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

getting 4.56s soon... got some???s

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by muddysub, May 29, 2002.

  1. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

    Joined:
    Jun 23, 2001
    Posts:
    10,452
    Likes Received:
    489
    Location:
    my garage, Henderson, NV
    okay ya'll say how bad it is to run in 4-hi on the road, then how the heck do you break in the front gears? if it's so bad for the truck to run with the hubs locked in what do i do? i've done 1 rear end swap before so i know what i'm doing /forums/images/icons/crazy.gif(kinda) so how long will it take me and a buddie or two to do both axles? i'm afraid the suburban will be down for a week and i'll have to drive daddy's f*rd. /forums/images/icons/crazy.gif
     
  2. Blazinaire

    Blazinaire 1/2 ton status

    Joined:
    Mar 17, 2002
    Posts:
    1,262
    Likes Received:
    0
    Location:
    Santa Maria, CA
    I will have my front gears (4.56) installed soon, and want to know the same thing about breaking them in. Maybe run in 4hi with the hubs unlocked, so it will still rotate the gears with pressure on them, but not be driving the wheels, as apposed to running the hubs locked and the case in 2hi?
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,063
    Likes Received:
    70
    Location:
    Pleasanton, CA.
    There will not be any pressure on the gears if you drive in 4hi with the hubs unlocked. You will not damage anything by running in 4hi on the street or highway. Think about it for a minute, trucks with original NP203 case is a fulltime 4x4. It doesn't know if you are in dirt or highway. And before anyone brings up the fact about there being a differential in a NP203 case I know that. There still will not be any damage from running in 4hi on the highway. Besides, it's not like you are going to do it just because and for any length of time either, just to break in the new gears then back to 2hi
     
  4. Blazinaire

    Blazinaire 1/2 ton status

    Joined:
    Mar 17, 2002
    Posts:
    1,262
    Likes Received:
    0
    Location:
    Santa Maria, CA
    What about my truck with the 208? And doesn't Muddysub's have a 241?
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

    Joined:
    Dec 14, 2001
    Posts:
    22,063
    Likes Received:
    70
    Location:
    Pleasanton, CA.
    It doesn't matter what trans case you have, it will not hurt it unless for some crazy reason you have different gear ratios in your diffs. I have a NP241 in my truck as well.
     
  6. Blazinaire

    Blazinaire 1/2 ton status

    Joined:
    Mar 17, 2002
    Posts:
    1,262
    Likes Received:
    0
    Location:
    Santa Maria, CA
    But when you turn, doesn't the frontend have to travel further/faster than the rear end, so that would create bind in the transfer case? My truck would always "hop" in a tight turn on high traction surfaces shortly followed by one of the front wheels slipping. It would be pretty lame trying to explain to my friends how I broke a front axle u-joint while on the street! And... the recommended break in period is 500 miles, that is a lot of miles to be in 4wd on the street!
     
  7. Sandman

    Sandman 3/4 ton status Author

    Joined:
    Apr 15, 2002
    Posts:
    5,653
    Likes Received:
    0
    Location:
    Pocatello, ID
    The 203 has an internal differential built into it that allows give between the front and the rear axles. This allows you to drive on the pavement with it. The other transfer cases (205,208, etc) that do not have some type of slip-allowing will bind up on the street. Especially when cornering. Looks like you will be forced to take extended off-road trips. Bummer.
     
  8. four_by_ken

    four_by_ken 1/2 ton status

    Joined:
    Jun 9, 2001
    Posts:
    3,806
    Likes Received:
    0
    Location:
    Allenton, MI
    Personally. I would not drive on the street for 500 miiles in 4wd. Just me though.

    I will just break them in wheeling on my own vehicle.

    Ken H.
     
  9. txbartman

    txbartman 1/2 ton status

    Joined:
    Jun 1, 2001
    Posts:
    1,975
    Likes Received:
    0
    Location:
    Plano, TX
    You can drive in 4WD with the hubs unlocked, but you can risk some damage to your hub gears (though not likely). You can also run with the hubs locked but in 2WD. Neither of these will put much pressure or load on the gears, but it is better than nothing.

    I ran mine like that for quite some time after installing my 4.56s. Then I just took it easy for a while when off-roading. They have worked like a charm for me.
     
  10. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    You should provide your mailing address, so that the folks that follow your advice can send you a bill for their repairs. /forums/images/icons/shocked.gif
     
  11. wayne

    wayne 3/4 ton status

    Joined:
    Feb 1, 2001
    Posts:
    6,178
    Likes Received:
    0
    Location:
    Carlisle, Pa
    I would not worry about breaking in the front gears as much as the rear. If you have any dirt or gravel roads near you just run a few trips down them in 4 wheel.
     
  12. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

    Joined:
    Jun 23, 2001
    Posts:
    10,452
    Likes Received:
    489
    Location:
    my garage, Henderson, NV
    thanks guys! /forums/images/icons/smile.gif i think i'll just run with the hubs locked in 2-hi unless someone else tells me otherwise. oh and the extended off road trip... that's gonna be rough, really. /forums/images/icons/frown.gif/forums/images/icons/wink.gif
     
  13. 70~K5

    70~K5 1/2 ton status

    Joined:
    Apr 13, 2002
    Posts:
    2,032
    Likes Received:
    0
    Location:
    sillycon valley
    Take your rear driveshaft off and run in 4W hi. Then your powering the front only. You can't do this if you have a rear slip joint on the TC.
     
  14. four_by_ken

    four_by_ken 1/2 ton status

    Joined:
    Jun 9, 2001
    Posts:
    3,806
    Likes Received:
    0
    Location:
    Allenton, MI
    Hehe. /forums/images/icons/smile.gif

    Send the bill.

    Ken H.
     
  15. 91K5

    91K5 1/2 ton status

    Joined:
    Jul 5, 2000
    Posts:
    185
    Likes Received:
    0
    Location:
    Wichita, Kansas
    Find a long stretch of dirt road, put it in 4 hi, and drive about 10 minutes or 15 miles, then take a long lunch break and let the gears and oil cool down. You have to have the front hubs locked otherwise the wear pattern it establishes wont be for the axle under a load. Keep in mind if you have to drive somewhere where before you can drive it in 4 hi, that counts as time and mileage and you have to let it cool before you go break in the front gears. Keep it under 60 mph as well.
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

    Joined:
    May 30, 2001
    Posts:
    17,669
    Likes Received:
    0
    Location:
    IL, USA
    That's what I'd do. Hubs locked, 2 hi. Run it 50 miles and let it cool, run it a little more, and call it broke in.
     

Share This Page