Cost to replace an automatic transmission - 2008 Pontiac Grand Prix

It is generally not possible to replace a manual transmission with an automatic transmission in a vehicle. This is because the two types of transmissions have different internal components and use different methods of transmitting power from the engine to the wheels. In order to replace a manual transmission with an automatic transmission, you would need to make significant modifications to the vehicle's drivetrain and possibly to the engine as well.
Additionally, the cost and complexity of such a conversion would likely be much higher than simply replacing the existing transmission with a new manual transmission. In most cases, it is more practical to repair or replace the existing manual transmission rather than attempting a conversion to an automatic transmission

May I offer a suggestion, if you are not a mechanic on transmission take it and get it repaired. The speed sensors are in the transmission, you will have to take the oil pan off then valve body but first drain the fluid then you will have a internal or input sensor then a output sensor [speed] if you are not familiar you could cost major cost of repairs hope this helps and Good Luck Mike L

Reynald, Check your transmissions fluid level and top up if needed as a first step. Vehicle should be scanned for diagnostic codes to aide in finding the fault and repair required. Could be the plugged trans. filter, shift solenoids stuck/faulty, pressure switch,etc. Check the attached links,instruction and guides, Good luck
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Transmission Solenoid Symptoms Replacement Cost
Diagnosing Automatic Transmission Problems
http://www.craigsautos.com.au/transmission-info/6-diagnose

Transmission Solenoids ' Symptoms ' Replacement ' Cost

myautomatictransmission.com/automatic-transmission-solenoids.htm
A transmission solenoid is an electro-mechanical or electro-hydraulic valve that ... the faulty solenoid located on the valve body and replacing it with a new one.

If it is a 2 wheel drive, should be pretty cheap. The drive shaft comes out, the seal comes out, and the install is reverse.
You can check the cost of the part online for your area and whatever the labor rate is for your area, I would say 1 - 2 hrs.

For Automatic transmission problem,click the link below:---- 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.

Depending on where you get the transmission it will run $800 to $2000 plus installation cost unless you do that yourself. It is usually cheaper to rebuild the transmission than replace it out right unless your converting from Manual to Automatic.

I assume you mean the speed sensor. The part should cost ~$15.00 and labor will be 1 hour or less.

Typically, if you have the replacement transmission it will cost around 800 depending on where you go. I have no data on what the transmission will cost you in your area.

Wel From Your Discription This is A Slipping CLUTCH If its a Manual Trans Requiring a CLUTCH JOB Consisting of Replacement Of the Fallowing,
1. Clutch Disc
2. Clutch Pressure Plate
3. Clutch Releace Bearing
4. Pilot Bearing or Bushing
5. Any Eng or Trans OIL SEAL Nessisary While Dissasymbled

If this Is A AUTOMATIC Transmission,
You Require That the Transmission be Replaced Or Rebuilt as There Is Serious Damage Done to the Clutch Packs In the Automatic trans that Can ONLY Be Corrected With A REBUILDING of the UNIT Or REPLACEMENT of the Unit.
Sorry to Be the Bearer of Bad News but This is Part of My Job too.
Good Luck and I Hope you find this to Be of Much HELP to you ! ! !