LOOK HERE!!! Trouble Code P1870.....for Harsh 1-2 Shifts.

Discussion in 'GM Powertrain' started by 99'HEARTBEAT, Nov 19, 2010.

  1. Van70style

    Van70style New Member

    This fix WORKS! I bought the valve and oring from Sonnax. No more issues, but I reused the old valve body.
  2. mybollsareonfire

    mybollsareonfire New Member

    my truck ran great and all and here recently i started to upgrade cuz you know how addicting it is ... sooo ive literally been on my pc for 12 hrs looking for wth is these codes that my baby is spittin out and a real definitive answer on the TCC solenoid on my truck it shifts right when i first ride in her and bout 30 to 1hr drive i go and stop in town and from a dead stop she jerks hard shifting into 1-2 gear and sometimes it'll shift hard 2-3 and 3-4 ive been looking on the net for quite sometime today and everybody has something diff. either unplug this take this off rep0lace that rebuild this just not the right answer and i love love loveeeeee my "Betsy" (thats her name lol) and i want her riding right ya know just like any other truck owner would ... im just worried that i might have to replace the tranny and really dont have the cash rite now but her are a few codes that i got and really hope my chevy bros can help (which i know yall can) ... so here goes nothing ...


    its a 2000 chevy silverado 5.3 ls ty in advanced
  3. Family Force 6

    Family Force 6 Rockstar 100 Posts

    I think I may have experienced this issue with my 99 Suburban this week on a road trip. We were in Yellowstone park and all of a sudden the upshifts were viscous hard. I was sweating it, thinking the worst, but hasn't done it since then.

    Van70style, how hard is the fix? The only thing I've done to a tranny is replace the fluid and filter. It looks like there are a million parts- a bit intimidating!

    I saw the Sonnax website and they recommend some tools to bore out the valve. Did you do that too?
  4. 30U Plymouth

    30U Plymouth New Member

    I've used this inexpensive part# A74741Q (www.fitzall.com) before and it works great.
    It can even be fixed without removing the valve body from the vehicle.

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