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SAS with autotrac

Discussion in 'The Garage' started by bluejeep, Apr 29, 2004.

  1. bluejeep

    bluejeep 1/2 ton status

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    Just wondering if anybody had any first hand experience with doing a SAS with an autotrac transfer case? Obviously with manual hubs the autotrac feature will not work, but other than the obvious any other issues? Thanks.
     
  2. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I am wondering some of the same things. I am probably going to buy a 3500HD duramax chevy or a Super duty ford next year and would like to strait axle the chevy if that is what I choose.
     
  3. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    When the ORU kits first came out Four Wheeler had one done. They changed the transfercase to a later model non-autotrac case with the correct drop. Otherwise with the driveshaft, there would of been serious vibration problem at highway speeds. /forums/images/graemlins/k5.gif
     
  4. willyswanter

    willyswanter 1/2 ton status GMOTM Winner

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    Yep, you have to swap to a non-autotrac case.
     
  5. bluejeep

    bluejeep 1/2 ton status

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    But would there be any problems with not using the autotrac feature? Correct me if I'm wrong, but 2hi should not present any driveshaft problems.
     
  6. bluejeep

    bluejeep 1/2 ton status

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    [ QUOTE ]
    Yep, you have to swap to a non-autotrac case.

    [/ QUOTE ]

    Have to, or want to for strength reasons? Willyswanter, did you have to relocate your catalytic converters when you did yours?
     
  7. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    But would there be any problems with not using the autotrac feature? Correct me if I'm wrong, but 2hi should not present any driveshaft problems.

    [/ QUOTE ]
    Exactly what I was thinking, whats it matter if it's a D60 or IFS up front? Driving around town you stay in 2HI and the hubs unlocked, if you want autotrac...lock the hubs and push the botton, right? 4hi and 4lo are the same.
     
  8. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    When not in 4wd , the front still comes on as needed, thats why its called AUTOTRAC /forums/images/graemlins/k5.gif
     
  9. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    When not in 4wd , the front still comes on as needed, thats why its called AUTOTRAC /forums/images/graemlins/k5.gif

    [/ QUOTE ]
    Far as I know that is incorrect, my dad has a 98' burb and there is a seperate button that says "AUTOTRAC" that has to be engaged to activate the autotrac feature, otherwise it is in 2wd. I am pretty sure I am correct but maybe not. /forums/images/graemlins/thinking.gif
     
  10. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Perhaps, I was just going off an article I read. Personally I only drive old stuff (wife drives new stuff) . But why take a chance, if there is a button, what if someone pushed it by accident ? /forums/images/graemlins/k5.gif

    There is a write up here : clicky here
     
  11. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    Perhaps, I was just going off an article I read. Personally I only drive old stuff (wife drives new stuff) . But why take a chance, if there is a button, what if someone pushed it by accident ? /forums/images/graemlins/k5.gif

    There is a write up here : clicky here

    [/ QUOTE ] It would be pretty hard to bump the button, it's in a good spot. Besides, if you accidently hit the button and you noticed some vibs...you or I would probably notice and just shift back to 2wd. Also IMHO if you don't have a shaft in there that is worthy to handle 25mph or so it shouldn't be in there.

    I know that when my dad's burb is in 2wd it doesn't get any help from the front...we go snowmobiling a lot during the winter and have been in light snow with it and spinning a little.
     
  12. willyswanter

    willyswanter 1/2 ton status GMOTM Winner

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    Well I know a guy that had autotrac in his tahoe and he ran it for maybe a month before it came out from under his truck in multiple pieces while driving down the road... Trust me, you HAVE to replace the case with a non-autotrac if you plan on running a front driveshat. You could get a custom shaft made to work with the autotrac but it would probagly still vibrate. Plus the case isn't all that strong to start with...
     
  13. 6.2Blazer

    6.2Blazer 1/2 ton status

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    As already mentioned, the autotrac cases have a 2wd mode that operates just like any other transfer case so I don't understand why you would have to swap it out???

    Regarding the autotrac mode, it only sends power to the front shaft when it senses tire slip. This does bring up a question as to whether it would function correctly depending on what is uses for this (i.e. if it uses the front tire speed sensors which it no longer has after a SAS)???
     
  14. bluejeep

    bluejeep 1/2 ton status

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    [ QUOTE ]
    This does bring up a question as to whether it would function correctly depending on what is uses for this (i.e. if it uses the front tire speed sensors which it no longer has after a SAS)???

    [/ QUOTE ]

    Spoke with ORU and they said there are two speed sensors in the transfer case, on on front output and one on the rear.

    Anybody know what the NP# is for the push-button non-autotrac transfer case is?
     
  15. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    [ QUOTE ]
    Anybody know what the NP# is for the push-button non-autotrac transfer case is?

    [/ QUOTE ]

    NP263 , should be a 2001 HD Chevy somewhere some idiot wrecked. Get one of those. /forums/images/graemlins/k5.gif
     
  16. bluejeep

    bluejeep 1/2 ton status

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    Is that the same as on the older body style (96-98) that would bolt up to a 4L60E?
     
  17. 6.2Blazer

    6.2Blazer 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    This does bring up a question as to whether it would function correctly depending on what is uses for this (i.e. if it uses the front tire speed sensors which it no longer has after a SAS)???

    [/ QUOTE ]

    Spoke with ORU and they said there are two speed sensors in the transfer case, on on front output and one on the rear.

    Anybody know what the NP# is for the push-button non-autotrac transfer case is?

    [/ QUOTE ]

    If this is the case, then on a SAS truck you could lock in the hubs and it should work. The only issue would be making sure the front driveshaft can operate at normal speeds without vibration. However, if you had the hubs unlocked the front driveshaft would not spin and therefore the t-case would think the back tires were spinning on the fronts were not and keep the front output engaged. But again, as long as the front driveshaft doesn't have any angle, binding, or vibration issues there shouldn't be a problem.
     
  18. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    [ QUOTE ]
    Is that the same as on the older body style (96-98) that would bolt up to a 4L60E?

    [/ QUOTE ]

    That I can't say for sure. I was just letting you know what ORU put in the Suburban they did for Four Wheeler. It never mentioned differences, it just appeared to be bolt on. /forums/images/graemlins/k5.gif
     
  19. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    Is that the same as on the older body style (96-98) that would bolt up to a 4L60E?

    [/ QUOTE ]

    You are thinking of an NV246.
     
  20. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    Well, I still don't understand why it won't work...whenthe auto case is in 2wd mode it is in only 2wd, no front movement at all. If I do a strait axle when I buy an 04' HD than I will run in 2hi in town, If I need 4wd than I will lock the hubs and put the case in full 4wd hi or low, Just like how my 241 in my K5 works. I still don't see how any damage could accur if a guy keeps it out of autotrac mode. /forums/images/graemlins/dunno.gif
     

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