Engine and transmission swap

Tiny
JAMESB2019
  • MEMBER
  • 2005 PONTIAC GRAND PRIX
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
I have a 3.9LZ and its FR3 3.69 4T65E Transmission. Is it possible to swap into the Grand Prix base? Briefly what's involved?
Thursday, March 24th, 2022 AT 5:45 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

Anything is possible, but the idea that everything will need to be changed is a bit overwhelming. The simple things like mounts will be different, the vacuum system and emissions components are different, the PCM/TCM are different, wiring harnesses need to be changed, and the list goes on. LOL

What is presently in the Grand Prix?

Joe
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Friday, March 25th, 2022 AT 2:05 PM
Tiny
JAMESB2019
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Lol! Well, the grand prix has 3.8 series III and 4T65E and everything a grand prix base has- complete and just sitting in our driveway. As you may know, we have a G6 GTP 3.9 that I had done numerous renewals on and then I ended up buying another 3.9 LZ engine along with its transmission just in case, but they have been sitting in storage as well (Lol!). I guess the swap will force the 3.8 and its transmissions into storage. I don't know what to do here: one of them has to go. Sister keeps calling me a "hoarder!" I am not- seriously. Thanks for the heads up though.
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Friday, March 25th, 2022 AT 8:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

You are very welcome. I have learned over the years when this type of job has been done, there always seems to be an issue. I'm not sure where you are located, but the issues usually include emissions issues which lead to the vehicle not passing inspection.

Regardless, please feel free to come back anytime in the future. You're always welcome here.

Take care,

Joe
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Saturday, March 26th, 2022 AT 11:47 AM
Tiny
JAMESB2019
  • MEMBER
  • 42 POSTS
  • 2006 PONTIAC G6
  • 3.9L
  • V6
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
Hello again,

I stopped working on this car because my sister is driving it, and she couldn't give it to me to fix it because "it took me too long last time." Please see past questions about this car's trasnmission.
I actually did not re open up the transmission after all. Instead, I myself pulled out an FR3 4T65E transmission from another G6 3.9L 2006. This second transmission sat in my garage for almost a year while my sister drove the car that has the transmission with the P0717-code problem. I decided to get professional transmission shops to replace the reluctor ring in the car she is driving. However, all of the transmission shops in North Carolina refused to do the work I asked of them, and I am not sure why. I asked them to open up the side cover and remove the valve body and channel plate to reach the reluctor ring and check it out. They all refused no matter how much I tried and offered to pay what they ask for. Every shop gave me the same story: "we can rebuild but cannot do what you asked." My question to you: would you agree, or would you say: something isn't right here? Obviously, when I was about to do the work myself, no one objected. Few days ago, I placed the second transmission I pulled myself from another G6 in the trunk of my sister's G6 and drove the car to the best shop in town: Cottman Transmission. I told them: "do one of three things: 1. Replace the internal harness, the ISS again and the check out the reluctor to see if it needs replacement 2. Rebuild the existing transmission (the one in the car that has the ISS code) or 3. Swap or rebuild and then swap the transmission I pulled out from another G6. 4 days later, I called them, and they said they decided to swap without rebuilding to see what happens the reason being "it is the best option because there were metal shavings in the pan of the transmission existing in the car right now. And that the transmission I pulled out myself from another G6 looks great but obviously won't know until after the swap." What do you think? The cost of swapping without rebuilding this second transmission?1400 dollars. The cost of rebuilding the existing in the car transmission? 2200 dollars and the cost of opening the side cover and replacing the ISS again and the internal harness? 800 dollars. How about checking out and or replacing the reluctor? The answer is no "we won't do that." Let me know what you think as I would have had no problem choosing to check out the reluctor instead of swapping or rebuilding. While reaching the reluctor requires the shops to remove the channel plate and valve body, it should not be all that hard and rebuilding is no easy task either.
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Tuesday, August 2nd, 2022 AT 11:46 AM (Merged)

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