2000 Silverado transmission issues

Discussion in 'GM Powertrain' started by Sooner22, Nov 8, 2010.

  1. Sooner22

    Sooner22 New Member

    This is going to be a novel, so i apologize in advance. I've recently had a trouble codes 1870 and P0758. The transmission has been starting in limp mode in what i believe is 3rd gear. This occurs pretty much every morning and only intermittently in the afternoon. I had 3 different shops around town tell me that I needed a rebuild. I finally caved in and went with a rebuild. The shop told me that the rebuild fixed my 1870 code, but that the shift solenoid B code (p0758) was still there. They also said that my transmission had only minor wear, and it really didn't need to be replaced after rebuilding it. They did go ahead and replace everything as per their standard rebuild. So i found out about the ignition switch and had that replaced as well. However, this hasn't fixed my problem. Tonight on advice from my uncle, I had the battery checked at Autozone. It was found to be bad. So i replaced the battery, and not even 1/4 mile down the road my SES light comes back on with the same p0758. The guy who fixed my transmission mentioned it could be the computer, but I'm a little tired of replacing parts and not getting results. I'm tempted to take it to a dealership and pay the hefty price tag for a diagnosis, but i don't know how they'd feel if they diagnose it and I want to fix myself, if possible. Anyone have any ideas? I appreciate any feedback you may give. If you need any other info please don't hesitate to ask.

    2000 Chevrolet Silverado Z71 5.3L V8

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    Sorry for your transmission problems,........read the following it will help you in understanding....why a code....P1870 is coming up,

    A Code.....P1870......is telling you there's a Problem with the Control Valve Body in your Transmission.

    Below is a G.M. Service Bulletin,that might apply to your Vehicle,
    TSB # 01-07-30-023A
    Harsh 1-2 Upshift, SES, MIL, or CEL Illuminated, DTC P1870 Set (Replace Valve Body)

    1996 Buick Roadmaster
    1996 Cadillac Fleetwood
    1999-2000 Cadillac Escalade
    1996-2000 Chevrolet Camaro, Corvette
    1996-2000 Pontiac Firebird
    1996-2000 Chevrolet and GMC Light Duty Truck Models
    1996-2000 Oldsmobile Bravada

    With 4L60-E Automatic Transmission (RPO M30)
    Built Prior to January 15, 1999 (Julian Date 9015)
    This bulletin is being revised to update the Parts Information

    Please discard Corporate Bulletin Number 01-07-30-023 (Section 07 -- Transmission/Transaxle).

    .......Some customers may comment on a Harsh 1-2 up-shift and the Check Engine Light or Service Engine Soon indicator is illuminated.
    .......Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.

    .......The scan tool may show a DTC P1870 set as a history code.
    ........A Harsh 1-2 Shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93°C (200°F).

    ......The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply

    ......DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.
    ......When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
    ......This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).
    ......When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
    ......When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), ......Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).

    Install a control valve body with the revised TCC regulator and isolator valves. These valves are used in all transmissions produced after January 15, 1999 (Julian Date 9015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.

    ......If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.
    .......Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).
    ......The torque converter is not blue or overheated.
    ......The transmission fluid is not burned or has no burned odor.
    ......The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments).

    Last edited: Nov 3, 2013
  3. Sooner22

    Sooner22 New Member

    Well, I should have posted here before having the transmission rebuilt. Any ideas on why i'm still getting the P0758 code, and whether replacing the computer would be an appropriate next step?

    99'HEARTBEAT MODERATOR Staff Member 5+ Years ROTM Winner 1000 Posts Platinum Contributor

    On the Code P0758,
    .....Circuit Description
    The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The solenoid is a normally-open exhaust valve. With the 1-2 SS valve, the 2-3 SS valve allows 4 different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 2-3 SS valve receives ignition voltage through the ignition 0 voltage circuit. The powertrain control module (PCM) controls the solenoid by providing the ground path on the 2-3 SS valve control circuit.

    When the PCM detects a continuous open, short to ground or short to voltage in the 2-3 SS valve circuit, then DTC P0758 sets. DTC P0758 is a type A DTC.

    DTC Descriptor
    This diagnostic procedure supports the following DTC:

    DTC P0758 2-3 Shift Solenoid (SS) Control Circuit

    Conditions for Running the DTC
    The system voltage is 10-18 volts.
    The engine speed is greater than 450 RPM for 5 seconds.
    The engine is not in fuel cutoff.
    Conditions for Setting the DTC
    DTC P0758 sets if one of the following conditions occurs for 5 seconds:

    Condition 1
    The PCM commands the solenoid ON and the voltage feedback remains high, B+.

    Condition 2
    The PCM commands the solenoid OFF and the voltage feedback remains low, 0 volts.

    Action Taken When the DTC Sets
    The PCM illuminates the malfunction indicator lamp (MIL).
    The PCM commands third gear only.
    The PCM commands maximum line pressure.
    The PCM inhibits TCC engagement.
    The PCM freezes shift adapts from being updated.
    The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
    The PCM stores DTC P0758 in PCM history.
    Conditions for Clearing the MIL/DTC
    The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    A scan tool can clear the MIL/DTC.
    The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
    The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.
    Diagnostic Aids
    Refer to the Shift Solenoid Valve State and Gear Ratio .

    Test Description
    The numbers below refer to the step numbers on the diagnostic table.

    This step tests the function of the 2-3 SS valve and the automatic transmission (AT) wiring harness assembly.

    This step tests for power to the 2-3 SS valve from the ignition through the fuse.

    This step tests the ability of the PCM and of the wiring to control the ground circuit.

    This step measures the resistance of the AT wiring harness assembly and of the 2-3 SS valve.
  5. dpower

    dpower New Member

    Hey guys, I have seen this post (and countless others on other sites) concerning the 1870 code. My tranny did this to a T. I suffered with it for over 2 years. I finallyhad to address the issue because my truck wouldn't pass emissions. I talked to a local tranny shop and he said it needed a new $2400 tranny rebuild. I went to the Chevy dealer to price out a TCC valve. Had to buy the entire valve body for $365. And this was still no guarantee that it would fix it.

    So I broke down and bought all of the shift soleniods, including the TCC. Put these in, filled it with 6qts of Dex 6, a new filter and......

    It shifts as smooth as a babys butt. No more SES code, no 1870 code, plus it runs like it gained 20 hp. I guess I didn't realize that its sluggishness was due to the tranny slipping. It doens't bang into 2 and 3rd anymore and best of all, it passed emissions.

    So for $124 in parts and 2 hours of my time, I saved myself a bunch of money and trouble.

    Oh by the way, its a 2000 Silverado 5.3 with 165,000 miles on it.

    Just an FYI for those trying to fix theirs.
  6. dpeter

    dpeter Epic Member 5+ Years 500 Posts

    Could you post the part numbers and describe the job and any difficulties you may have run into. I have same engine trans combo in my 2000 Yukon and am beginning to experience similar issues. I assume the transmission did not have to be removed for these repairs?
  7. dpower

    dpower New Member

    I can't post the exact part numbers because I didn't save any of the boxes. But I replaced both the 1-2 and 2-3 solenoids, the TCC solenoid plus another that was also called a TCC solenoid. Three of the four simply unclipped from the harness, but the TCC had to have the wires spliced, which was no big deal. That one actually extends up into the pump I believe. The only difficulty I had was laying on my back while doing this and getting tranny fluid all over me. One thing you want to watch for is that if you have the original tranny oil pan, and if it has a drain plug, you may find it to be seized in there tight. Its a common problem. I replaced mine with an aftermarket one to eliminate that issue. I've heard many a horror tale about how bad this problem can be, but I tried the cheapest and easiest one first and got lucky.

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