Vortec 454/4L80e HD swapped 1999 Tahoe OBS

6.0 Carb Conversion or Stay EFI?

  • Carb Conversion

    Votes: 0 0.0%

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    3
  • Poll closed .

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bigfootchiro

bigfootchiro

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Dammit! Didn’t you just put that bish in?!?

She’s only got about 40K miles on her, but it came out of a motorhome. Serviced and had new servos put in, too. This all started when the TC stopped locking up. Then I lost OD right after. Now a couple months later and this happens
 

Sam Harris

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She’s only got about 40K miles on her, but it came out of a motorhome. Serviced and had new servos put in, too. This all started when the TC stopped locking up. Then I lost OD right after. Now a couple months later and this happens
Dammit! Well, for some reason I thought you had a newer one in there. At least it’s not happening in a new tranny. Sorry I don’t have anything useful to offer. I know the clutch packs are for more than one gear, so perhaps one of the clutch packs has failed? I can’t remember what packs go with what gears. [emoji53]
 

swathdiver

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Alright guys, more issues arise! Transmission time... let’s hear everyone’s input!

Haven’t pulled the pan yet, but I only have 3rd gear. The other day it would start in 3rd, and when I stepped on the throttle it would downshift to 1st, then 2nd, and quick shift into 3rd. But then at times it acted normal. Started truck up on Saturday and it won’t come out of 3rd gear. So it starts in 3rd and drives in 3rd. Nothing changes when I manually shift. I have Reverse, as well. I have cleared the adaptive tables to try and take it out of possible limp mode, and that did nothing. Supposedly this transmission defaults to 2nd when in limp mode, but I am most definitely in 3rd.

Any input is greatly appreciated!

I know you have a 4L85 so understand that this came from my shop manual for the 4L65/4L70. It says 3rd gear only means that 12 volts is not getting to the transmission. There could be a pinched solenoid wire or a solenoid is not grounded anymore.

Now, if it starts in 3rd and can't shift out of 3rd, the book says to check the detent lever and manual valve that attaches to it. Could have lost a nut and they separated.
 

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I know you have a 4L85 so understand that this came from my shop manual for the 4L65/4L70. It says 3rd gear only means that 12 volts is not getting to the transmission. There could be a pinched solenoid wire or a solenoid is not grounded anymore.

Now, if it starts in 3rd and can't shift out of 3rd, the book says to check the detent lever and manual valve that attaches to it. Could have lost a nut and they separated.
That would be a nice fix!
 
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bigfootchiro

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Dammit! Well, for some reason I thought you had a newer one in there. At least it’s not happening in a new tranny. Sorry I don’t have anything useful to offer. I know the clutch packs are for more than one gear, so perhaps one of the clutch packs has failed? I can’t remember what packs go with what gears. [emoji53]

it’s all good! I appreciate the support.

I know you have a 4L85 so understand that this came from my shop manual for the 4L65/4L70. It says 3rd gear only means that 12 volts is not getting to the transmission. There could be a pinched solenoid wire or a solenoid is not grounded anymore.

Now, if it starts in 3rd and can't shift out of 3rd, the book says to check the detent lever and manual valve that attaches to it. Could have lost a nut and they separated.

I was thinking about the 12V signal, which can still be true. Just today, it started binding up on me. Going down the road, it starts binding, and slows me to a stop. Can’t go forward at all. When that happened, you could smell a lot of burning fluid/clutches. Shifted into Park, back into gear, and it released. Was able to drive it all the way to my office. On the way home tonight, it did it again. Shifted into Neutral, back into gear, and it released.

Still going to have the 12V signal checked and all wiring, but probably need a rebuild at this point in time. Will be interesting to see what the insides look like
 
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bigfootchiro

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Any updates?

Found out internal harness had been coming loose and shorting out. Wrecked havoc. Probably what caused me to lose TC lockup, jerking sensations, and lots of clutch material in pan. Gonna go with a built transmission probably when we leave for our honeymoon, so it’s done by the time we get back.
 

Onebad1983

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Found out internal harness had been coming loose and shorting out. Wrecked havoc. Probably what caused me to lose TC lockup, jerking sensations, and lots of clutch material in pan. Gonna go with a built transmission probably when we leave for our honeymoon, so it’s done by the time we get back.
Well you hadn't updated in 5 months I was worried man. As you can see, I've been busy :(
 

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