No Power to Transmission

Discussion in 'Engine & Drivetrain' started by bluebear15, Jul 10, 2018.

  1. bluebear15

    bluebear15 Full Access Member

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    The other week on my 2006 Tahoe Z71 I got in it to go to work and noticed it was way bogged down when taking off like it was in "limp" mode. I checked the transmission fluid and had to add 4oz short of 2 quarts to get the level back up in the checkerboard. Still drove the same after that. I had previously had a check engine light on for the week before due to the evap code. So I replaced the canister and valve to take care of the evap code. When I went to clear the evap code (assuming that was the only one still there from the last time I scanned it) I saw a bunch of transmission codes pop up particularly P0758. I took it in to one of the local transmission shops that did the rebuild of the transmission on my old '97 Tahoe about 8 years ago thinking they did good work and would be able to fix it for me.

    They scanned the codes and had pretty much every transmission code come up. They dropped the pan and checked what they could inside and that all looked good. They told me the transmission didn't have power to it and it was some type of electrical or connection issue that they couldn't fix.

    It seems to drive fine when I manually shift but when in "D" I try to take off from a stop and it's really bogged down and takes forever to get up to speed and then seems fine after. Almost like it is stuck in 3rd gear taking off or in "limp" mode or something. Looking for any help possible as this is my daily driver. Thanks.
     
  2. swathdiver

    swathdiver Full Access Member

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    Do you have access to a Tech2? Can you post up all of the codes that are active and in history? I do not have that trouble code (P0758) in my shop manual for the 4-speed, but it is for the later body style.

    I had a number of codes pop up last year on another vehicle's transmission, I cleared them out and the car started working fine again and they haven't returned. Mechanically, the problem sounds like your torque converter but stuck or broken solenoids could be preventing the proper operation of the transmission.
     
  3. bluebear15

    bluebear15 Full Access Member

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    I do not have access to a Tech2 unless I just take it to the dealer and have them do it.

    When I scanned it I got all the following codes: P0740; P0753; P0758; P0785; P2761. I cleared them and they came back right away.

    When the shop scanned it they just told me it showed pretty much every transmission code.

    The shop is a reputable transmission shop. They said it was more of an electrical issue than something mechanical in the transmission since they looked it over. I've done some research on the web and I'm finding similar electrical issues. But everyone pretty much seems to just say get a wiring diagram and multi-meter and good luck. I'm looking for any further input as well as any wiring diagrams
     
  4. swathdiver

    swathdiver Full Access Member

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    Well, I only have the last code, for the torque converter, in my shop manual. You can get instant access to the shop manual for your truck over at AllDataDIY, it's a subscription based service. You can also buy it in pdf form from SeriousCTBuyer on ebay. This will give you the description of the codes and wiring diagrams and everything else for your truck.

    If the multimeter and test light fail to find the problem, strongly consider the purchase of a Tech2.
     
  5. Scottydoggs

    Scottydoggs Full Access Member

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    you check for a bad fuse as crazy as it sounds? my regal has a tcc fuse, pull it and the tc is locked up fully.
     
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  6. bluebear15

    bluebear15 Full Access Member

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    That's what I'm going to be looking at tonight. I just picked it up from the shop today and haven't had a chance yet to look at the fuses.
     
  7. Doubeleive

    Doubeleive Elite Member Supporting Member

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    sounds like a serious short or something has disconnected along the harness somewhere, but I suppose the transmission shop would have at least looked for that as well as any related fuse.
     
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  8. bluebear15

    bluebear15 Full Access Member

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    Ended up being fuse related
     

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