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My transmission not shifting properly can we fix it?

Tiny
JOEYSISCO99
  • MEMBER
  • 2014 CHEVROLET SILVERADO
  • 4.3L
  • V6
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
Purchased the truck listed above use work truck. Shifts into reverse and moves no issues, will start into first gear and move, tries to shift into second (as seen on the dash gear select) and bounces back to first. I scanned and have no active or pending codes in the ECU, none at all. I checked the transmission fluid and it doesn't smell burnt. Ideas?
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Saturday, December 12th, 2020 AT 1:54 PM

44 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,874 POSTS
Hi,

By any chance, have you scanned the can-bus system? CAN stands for controller area network. It will cover all computers/modules on the vehicle. There could be something your scanner can't read.

Here is a video showing what I am referring to:

https://youtu.be/InIlnsjOVFA

If I am understanding correctly, when you shift (manually) between first and second, it jumps back to first. What happens in drive?

Let me know.
Joe

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Saturday, December 12th, 2020 AT 8:40 PM
Tiny
FRANCISCO PACO GUTIERREZ
  • MEMBER
  • 1 POST
  • 2008 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 149,000 MILES
The 02 sensor fuse not tight loose at terminals and the engine is stalling. Transmission not shifting properly.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Hey FRANCISCO,

This sounds like you have a catalytic converter that is plugged causing the problem you have described.

Here is a guide and a video to help you get the problem fixed.

Also tighten the fuse holder by enhancing the tension on the fuse holder terminals.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

and

https://youtu.be/CORe9JyrexI

and

https://www.2carpros.com/articles/stall-at-idle

Please run some tests and get back to us so we can continue helping you.

Best, Ken

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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
ANTHONY 70577
  • MEMBER
  • 3 POSTS
  • 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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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
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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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
ANTHONY 70577
  • MEMBER
  • 3 POSTS
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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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
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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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
JCT
  • MEMBER
  • 1 POST
  • 2006 CHEVROLET SILVERADO
  • 4.3L
  • V6
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
Transmission goes straight from first gear to fourth gear. No second or third. Replaced both shift solenoids, fluid, and filter, but did not help. Fluid did have some sludge in it. No DTC's present. Any ideas?
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,363 POSTS
Hello,

Because there is no troubles codes I am wondering if the PCM has gone bad. Also I have seen the transmission selector switch cause some weird problem when they go out.

Here are diagrams both of their locations. (Below)

Please let us know what happens, we are interested to see what it is.

Cheers, Ken
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
ANTHONY 70577
  • MEMBER
  • 3 POSTS
I replaced the PCM that fixed it thank you.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
BLOOMEE
  • MEMBER
  • 1 POST
  • 2005 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 65,000 MILES
My pickup was running and performing fine. I had my truck serviced in preparation for a long trip. The dealer suggested that the transmission fluid be changed and the transmission be flushed. I agreed. Immediately after servicing the transmission a problem developed. Between 40 and about 60 mph it feels as if it is trying to shift dow and then up, you can feel a "bump". If I carefully hold a constant speed, usually around 53 mph and 1500 rpm, the Transmission repeatedly shifts back and forth at probably 20 hertz causing a tremendous vibration. They changed the torque converter and the problem remains.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
JNOVACK
  • MECHANIC
  • 723 POSTS
Inspect Transmission Kickdown Solenoid Faulty transmission kickdown solenoid or solenoid circuit.

Inspect Transmission Modulator - (A/T) Worn leaking or faulty transmission modulator valve or vacuum system.

Inspect Transmission Shift Linkage (Auto) Broken or improperly adjusted shift linkage.

Inspect Transmission Shift Linkage (Manual) Broken or improperly adjusted shift linkage.

Inspect Transmission Temperature Sensor Damaged, worn, or faulty transmission temperature sensor or transmission temperature sensor circuit.

Inspect Transmission Filter (A/T) Clogged or dirty transmission filter.

Inspect Transmission Cable Detent (A/T) Damaged, worn, or incorrectly adjusted transmission detent cable.

Inspect Transmission Cable Shift (A/T) Worn, or incorrectly adjusted transmission shift cable.

Inspect Transmission Cable Shift (M/T) Worn, or incorrectly adjusted transmission shift cable.

Inspect Transmission Control Module Damaged or faulty transmission control module or circuit.

Inspect Transmission Control Solenoid Damaged or faulty transmission control solenoid or circuit.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
JOSHKELLEY
  • MEMBER
  • 1 POST
  • 2005 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 42,100 MILES
I was driving down the free way when the rear end broke, at that time it shut the truck off and brake, abs, service bake came on. Rebuilt the rear end but now there is no drive and third gear, but it does have first and second manually then it will shift to third but no drive? Thanks josh
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
There are several Tech bulletins on your transmission, Most involve a reprogram of the PCM...some involve parts replacement, Any codes? SES light on? These guides can help us fix it

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

and

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

Please run down these guides and report back.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
BEAUMONTBOY82
  • MEMBER
  • 1 POST
  • 2005 CHEVROLET SILVERADO
  • 4.8L
  • V8
  • 2WD
  • AUTOMATIC
  • 146,000 MILES
The truck will not shift out of second and engine light is flashing. But you can clear codes and runs fine again when idling. Seems like every time you scan it is different codes it is not consistent. Started out trying to diagnose cause transmission would not shift and threw a shift solenoid B code. I have changed the shift solenoids and checked and cleaned all grounds, and check all fuses they are all good. Still only goes in reverse and second gear.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Can you get a live date scanner and watch to see what is actually going on with the solenoids, this will show the operation of each shift solenoid, if the solenoid is opening and you have no gear selection, you will probably have an internal mechanical fault with the transmission. Also a line pressure check will be a good idea.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
BRANDAN24
  • MEMBER
  • 2 POSTS
  • 2003 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
I went to passing gear on the highway but after a few seconds the truck dropped to 2nd gear. Now I am unable to shift auto nor manually into 3ed or 4th. P, R, N, 1-2 gears all fine. When I attempt to go over 35mph the engine will rev but not upshift to 3ed gear. 2ed to 1st and 1st to 2ed are fine. Could it just be the shift solenoids or PCM? No check engine light. I don't have the money for a rebuild. Please help!
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,874 POSTS
Without the check engine light, it becomes a guessing game. It sounds like it could be the shift solenoid, but the TCM may be causing problems.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
BRANDAN24
  • MEMBER
  • 2 POSTS
Are you suggesting the throttle conl mod? I didn't see a trans conl mod. The dealer tells me only the Allision has a trans mod. My 1500 is just a base model V6. There are 3 shift solenoids, witch one should I start with? I don't have the $150 to buy all.

Thanks for your help
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,874 POSTS
The 3-4 shift solenoid.
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Thursday, May 6th, 2021 AT 10:31 AM (Merged)

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