Transmission will not shift into overdrive replaced filter and fluid check engine light is on fluid seemed to different color from one side of the filter to other all five codes are on did shift to 3rd 2 to 3 times no warnings of any prior problems that something was wrong just turned 80,000 miles 1998 2.7 could it be solenoid pack or something else

The erratic jumping in and out of overdrive (O/D) on your 2006 Terrano 3GMR with a 3.2L engine could be caused by a few different issues. Here are some possible causes and fixes:

1. Faulty speed sensor: The speed sensor provides input to the transmission control module (TCM) to determine when to engage overdrive. A faulty sensor can cause the TCM to think the vehicle is going too slow or too fast for overdrive engagement. A mechanic can test the speed sensor and replace it if necessary.
2. Low transmission fluid level: Low transmission fluid level can cause the transmission to shift erratically or not engage overdrive. Check the transmission fluid level and add fluid as necessary. If the fluid level is low, it's important to also check for any leaks that may be causing the fluid loss.
3. Worn or damaged overdrive band: The overdrive band is responsible for engaging and disengaging overdrive. If the band is worn or damaged, it may not engage properly. A mechanic can inspect the overdrive band and replace it if necessary.
4. Transmission control module (TCM) issues: The TCM controls the shifting and engagement of overdrive. If the TCM is malfunctioning, it may not engage overdrive or cause erratic shifting. A mechanic can test the TCM and replace it if necessary.

It's recommended to have a professional mechanic diagnose and repair the issue, as the transmission is a complex and vital component of the vehicle.

1. ransmission fluid: Low or dirty transmission fluid can cause a range of transmission issues, including loss of reverse and overdrive. Check the transmission fluid level and condition, and consider flushing and replacing the fluid if it is dirty or low.
2. Transmission filter: A clogged transmission filter can restrict the flow of fluid through the transmission and cause issues with reverse and overdrive. Consider replacing the transmission filter and flushing the fluid to see if this resolves the issue.
3. Shift solenoid: The shift solenoid is responsible for controlling the flow of fluid through the transmission to engage different gears. If the solenoid is faulty or damaged, it can cause issues with reverse and overdrive. Consider having the shift solenoid tested and replaced if necessary.
4. Valve body: The valve body is a complex component within the transmission that helps to control the flow of fluid and engage different gears. If the valve body is damaged or worn, it can cause issues with reverse and overdrive. Consider having the valve body inspected and replaced if necessary.
5. Internal transmission damage: If none of the above issues resolve the problem, there may be internal damage within the transmission that is causing the loss of reverse and overdrive. In this case, it may be necessary to have the transmission rebuilt or replaced.

It's important to address these issues promptly to prevent further damage to the transmission or other components in your Chevy Silverado

Are there any lights lit on the dash ? check engine , overdrive etc..
could be just a shift solenoid ... Try draining trans fluid an replacing filter. Have to drop transmission pan .. what's the fluid look like ? a nice pink color ? does it smell burnt ? Is it full ?

Have you checked the fluid level? Plus the color of the fluid. It could just need a transmission fluid & filter change.

sound like Modulator elect fault.... worth doing this first lot cheaper than tranny rebuild

For Automatic transmission problem,click the link below:----Overdrive light in the dash blinks? http://repairhelpcenter.blogspot.com/2012/01/overdrive-light-in-dash-blinks.html
--------- Automatic transmission troubleshooting:----

http://howtobyme.blogspot.com/2011/11/automatic-transmission-will-not-go-into.html

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Automatic transmission shift lever issues?-------

http://technoanswers.blogspot.com/2012/01/automatic-transmission-shift-lever-hard.html

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AUTOMATIC TRANSMISSION FLUID LEVEL? --

http://schematicsdiagram.blogspot.com/2011/07/how-to-check-automatic-transmission.html

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AUTOMATIC TRANSMISSION FLUID AND FILTER?

http://schematicsdiagram.blogspot.com/2011/07/how-to-change-automatic-transmission.html

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Transmission fault light on car dash?

http://schematicsdiagram.blogspot.com/2011/12/transmission-fault-light-on-car-dash.html

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Transmission shifting problem?

http://schematicsdiagram.blogspot.com/2012/01/transmission-shifting-problem-on-toyota.html

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Transmission Slips out of 2nd gear?

http://repairhelpcenter.blogspot.in/2012/02/transmission-slips-out-of-2nd-gear.html

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OD light flashing and transmission fluid leaking?

http://repairhelpcenter.blogspot.in/2012/02/od-light-flashing-and-transmission.html

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Why Transmission fluid leaks near radiator?

http://repairhelpcenter.blogspot.in/2012/02/transmission-fluid-leaks-near-radiator.html

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Transmission fluid leaking?

http://technoanswers.blogspot.in/2012/02/ford-windstar-transmission-fluid.html

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****** wont go in reverse?

http://technoanswers.blogspot.in/2012/02/dodge-neon-wont-go-in-reverse.html

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Automatic transmission will not go into reverse?

http://technoanswers.blogspot.in/2012/02/dodge-automatic-transmission-will-not.html

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Transmission is making buzzing noise?

http://technoanswers.blogspot.in/2012/02/transmission-is-making-buzzing-noise.html

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This will help.

Thanks.

This mean thet there are some problems of transmision and the computer doesn't allow you to overdrive becouse you can destroy it. It's a protection measure. You must go to service for a test.

is check engine light on? check the tps.

check the transmission fluid first .
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overdrive allows the engine to run at lower RPM's , which increases the fuel
economy and also the transmission runs cooler

Your transmission fluid contain water,thats why the colour of the fluid changed to pink.And of such the clutch is slipping causing the engine to reve up before shifting - Check transmission cooler.