Transmission not shifting properly

Tiny
ANTHONY 70577
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 337,000 MILES
Replaced transmission with four different freshly rebuilt transmissions and they all did the same thing. Shifts fine from first to second then goes into neutral and stalls, but if I push the tow haul button it shifts into third gear.
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Wednesday, June 24th, 2020 AT 4:09 AM

10 Replies

Tiny
ASEMASTER6371
  • EXPERT
Good morning,

Are there any codes set in the system?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

This sounds like a control issue, not mechanical.

Who determined the transmission was the issue?

https://www.2carpros.com/articles/automatic-transmission-problems

Did anyone re-flash the PCM?

Roy
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Wednesday, June 24th, 2020 AT 5:17 AM
Tiny
ANTHONY 70577
  • MEMBER
Transmission went out on the highway to avoid a wreck went back home in first gear first transmission lasted eight months and actually went out just sitting up about six months. Second transmission off the dump shift from first to second then neutral third transmission was an ordered rebuilt transmission did the same thing. Third transmission was freshly rebuilt inside out with everything brand new. No the PCM was not re-flashed because I can t go anywhere far enough to get it re-flashed and no transmission codes whatsoever.
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Wednesday, June 24th, 2020 AT 6:49 AM
Tiny
ASEMASTER6371
  • EXPERT
When the transmission was replaced, was the cooler replaced? Metal from the original failure may have contaminated the other units causing the issue.

Are you doing the repair yourself?

You could have a mobile mechanic come to you for the re-flash.

Roy
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Wednesday, June 24th, 2020 AT 6:52 AM
Tiny
ANTHONY 70577
  • MEMBER
I didn t do the repair as far as rebuilding the transmission myself, but I did do the install and I am a mobile mechanic ASR s certified with 25 years under my belt GM certified.
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Wednesday, June 24th, 2020 AT 7:00 AM
Tiny
ANTHONY 70577
  • MEMBER
Brand new torque converter, brand new cooler, brand new everything, four times in a row. Even brand new lines. I m not the average Joe that gets on here doing this under the carport or in the back yard under the shade tree. But thanks any ways was just wandering if anybody else ever ran into this problem. But I ll check with the transmission guy at the dealership where I ve been working for 13 years!
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Wednesday, June 24th, 2020 AT 7:03 AM
Tiny
ASEMASTER6371
  • EXPERT
Okay, did you replace the transmission cooler? My thoughts are that is the reason for the constant failure. Contamination of metal is a huge issue.

Roy
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Wednesday, June 24th, 2020 AT 7:05 AM
Tiny
ANTHONY 70577
  • MEMBER
Like I said before I m not just doing this the first time under the shade tree in my back yard. I m an ASE certified mechanic everything when I say everything was changed brand new because I know about contamination. I m not a duck everything was changed brand new all four times.
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Wednesday, June 24th, 2020 AT 7:08 AM
Tiny
ASEMASTER6371
  • EXPERT
Okay, then did you go through the wiring on the transmission? Did you manually shift the transmission with your scan tool?

Roy
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Wednesday, June 24th, 2020 AT 7:19 AM
Tiny
ANTHONY 70577
  • MEMBER
Yes nothing like it s stuck in limp mode.
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Wednesday, June 24th, 2020 AT 12:43 PM
Tiny
ASEMASTER6371
  • EXPERT
Okay, so it is not shifting from 1 to 2 anymore?

When you command 3rd gear, it does not shift from your scan tool?

Is this a 4L60 or 4L80 transmission?

This sounds like a control issue and I would start with the flashing to be sure it is the most current updates.

Roy
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Wednesday, June 24th, 2020 AT 12:52 PM

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