4R70W funny probs after stall install.

Discussion in 'Drivetrain' started by Orgawesome_98coyote, May 28, 2015.

  1. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Alright I guess I will put this out there and just see if anyone has seen this odd issue before or could give a little info as to shoot me in the right direction to figure this out. Car has a stock 4R70W in it with roughly 100k miles on it. It shifted fine ever since I have had it until I put the 2800 stall in it. It's still manageable and isn't undriveable by no means but I can't be sure whats going on internally lol! (Probably wearing it now) After the I put the stall in it sometimes wants to hold 2 gear and this seems to depend all on how much throttle you give it threw 2nd gear. Ive kinda thought that has something to do with it not being tuned and it wants to think your at wide open throttle. No biggy... The weirdest one Ive noticed is that large bumps make it jump out of gear lol. First time I noticed it I was going down the interstate with cruise set on 65, I hit a bump in the road and it jumps out of gear and held the cruise so it revved to 6k hahaha! Without cruise set it does the same thing. Any large bump and it just kicks out and you have to click it into neutral and back down to drive or something to get it to go back in gear. Thinking about doing the jmod upgrade anyway so who knows, it may change again. Also a tune needs to be done as well.
     
  2. Addermk2

    Addermk2 Well-Known Member

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  3. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    Did you make sure the shift linkage was adjusted correctly when you put the trans back in the car? Maybe the linkage is close enough to being neutral that the bump moves the selector valve just enough to bleed off clutch pressure.
     
  4. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Dude, thats a huge help. Thanks. Im thinking it may be the pressure switch?? I think thats what it's refered to as. Its the sensor thats part of the shifter linkage. Could be a accumulator prob too though... Both sound pretty convincing.
     
  5. Addermk2

    Addermk2 Well-Known Member

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    The MLPS isn't s pressure switch.
     
  6. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    What made you think it was an accumulator problem? I'm kind of new to the automotive transmission world, I do Allison transmissions for a living and I have rebuilt a few GM automatics but the automotive transmissions are so much different then what I'm used to do I don't really know how to troubleshoot them yet.
     
  7. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Ah, your right man. I see that now. I feel like a dumbass now lol.
     
  8. Addermk2

    Addermk2 Well-Known Member

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    it was very hard to read his post on my phone... since there are no breaks in the wall of text.

    I misread it as not shifting into 2nd..
     
  9. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    This one sounded like a good start to me but who knows. None of this started until after the stall so thats why I questioned it being a tunning issue? Shift points, pressure etc. etc.???

    The most likely cause for this is a malfunctioning Transmission Range Sensor. This sensor is located on the driver's side of the transmission with the shift linkage. If it is giving an improper signal it can cause the transmission to downshift. With the shifter in the OD position, first and second gear are applied through a one-way clutch, and do not have engine braking. This lack of engine braking will make first or second feel like neutral if the vehicle speed is high enough. This could also be caused by defective shift solenoids, or a poor wiring connection.
     
  10. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Whoa! Not sure why part of that text is black. Have to get your spectacles out to read that shit lol.
     
  11. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    No challenging here, I honestly didn't know how you were troubleshooting and was curious how you came up with it was all.




    So I guess to get started in any direction, it might be a good idea to go ahead and do the J-MOD and replace the transmission range sensor on the side of the trans. They can give some really funky readings when they are acting up. Also, since you will already be there, check your shift linkage adjustment and make sure they are dead nuts perfectly adjusted.
     
  12. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Ok this completely contradicts everything we have said here but im 99% sure this is some sort of wiring issue. Either some crossed wires or a bad ground. As i was driving it earlier i hit a a few bumps and what i noticed was im completely loosing fire for a second. The car dead misses like you killed it and the tac and gauges go to zero for a split second and the check engine light even flickers off then back on. Its just as though you killed the car for a second and when it comes back up its like it losses what gear its in and has to shift back in gear.... Soooooo let the rat chase begin lmao!
     
  13. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    Definitely check all the ground wires. Block, two up by the headlights, down by the starter, and then one right by the computer. I might have missed a few but I would start there.
     
  14. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Dude! Starter came off when i took the tranny out. Thats def where ill look first. Great advice, ill update soon.
     
  15. D3VST8R96GT

    D3VST8R96GT Well-Known Member

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    I had friend put my starter back on after I screwed up my shoulder and as soon as I drove it I had similar electrical issues.... the starter ground strap was contacting the tranny cooling lines .... reattached it and fixed it
     
  16. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Wasn't on the starter but it was a ground. Unhooked the battery before taking the starter off and the little body ground straight off tge battery was almost broke completely into. And my power wire was kinda sketchy. After re doing that i have not had a single issue.
     
  17. lwarrior1016

    lwarrior1016 Moderator Staff SN95 Supporter

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    Fantastic! Glad you got it taken care of man.
     
  18. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    Yep, just goes to show you that sometimes what seems to be a major issue is something extremely simple. :headbang:
     
  19. D3VST8R96GT

    D3VST8R96GT Well-Known Member

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    This thread just made me aware of how little Auto stuff we have .... I mean we don;t even have our own Jmod sticky (from what I saw at a glance). I will put a nice thread together this month hopefully about the Jmod. I would like to host the attachments on this site as cv net has been having trouble and other places have since expired.
     
  20. Orgawesome_98coyote

    Orgawesome_98coyote Member

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    I approve this message

    I think there is a snipet of it under the tech and how to section but a full how to.