2004 CVPI - 3rd Transmission Installed

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Jul 21, 2025
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Just thought I would share my latest transmission replacement. I own a 2004 Crown Victoria Police Interceptor.

Currently my rig has 400k miles. My first post on here (a few months ago) I uploaded pictures of all the latest engine work which was a full Ford Racing timing chain kit and a brand new ATI Super Damper. I also rebuilt the axles myself and upgraded to 3.55 Ford Racing Trac-Lok.

That said, about a month ago, my 2nd transmission failed on me in the same way the first original transmission failed in that all gears worked and the car was driveavble but the first gear would slip very badly. I believe now that the 4r70W is good to 220k and then it takes a dump.


So I got right to work on the 3rd transmission replacement. I jumped on a major deal of a lifetime, an already pulled transmission from a near mint condition 2004 Lincoln Town car at the junkyard. I spent 450$ for the transmission.

I decided while the good used transmission was out I opened up the valve body and installed a new BorgWarner EPC solenoid, a Superior Tuff plate, a new Sonnax overdrive pin and a Sonnax main pressure regulator valve. I also installed new check balls and a new input and output shaft seal. 2-3 accumulator piston was replaced also.

I also bought a new Ford OEM flexplate, a rebuilt Precision of New Hampton torque converter and new ARP bolts for the flexplate.

Fortunately, I live very close to one of the best transmission shops in the area and I had them do the swap for me. While the transmission was out I had them replace the rear main seal also as I had a nasty oil leak.

My goodness!! Without question my car runs better than ever!! Even the guys at the transmission shop were amazed at how well the car runs with such high mileage. The owner of the shop use to race Mustangs so he knows.

I personally believe the new EPC solenoid and new flexplate was the game changer.

Acceleration is just crisp and high speed freeway (80mph) the car has very little vibration and just simply asks to go faster.

Also, daily I have been checking my engine oil and the engine oil on the dipstick hasn't moved at all. That was the last leak I had and now everything around my oil pan is bone dry.

These little 4.6 Ford engines are amazing. My plans now are the Trickflow heads and long tube headers. That's all she needs now to push my car from a fun car to a fast and exciting car to drive.

I will also be using Mobil 1 ATF now. It exceeds Mercon V specs. Admittedly I had been using Super Tech Mercon V but even though I can't prove it the cheap price must come at some kind of cost.

As far as pictures, all the pictures show the good used unit except for the transmission facing the camera where you can clearly see the black oil leak where the torque converter would be. The main seal oil leak was so bad the flex plate flung oil everywhere.

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Thanks for the post and the pics! Do you have any information on service history and failure of the past transmissions? Cause?

Definitely recommend dropping the pan at the next engine oil change, or one year, to clean the pan and magnet(s). Adding extra magnets can really help keep the fluid clean.
 
I'm curious how the new flexplate makes your car drive much better? Did you just have flexplate on the brain and mean to say torque converter?

Over time a flexplate can develop stress cracks due to fatigue. I don't have any proof this was the case in my situation, however.

That said, anyone with a older panther that has a civilian model buy the new Ford OEM flexplate anyway because the the updated flexplate is machined to accept 2 different size torque converters.

With the updated Ford flexplate you can use the police or Mercury Marauder style (diameter: 11.750) torque converter.

https://gopnh.com/Ford-Transmissions/4R70W
 
Thanks for the post and the pics! Do you have any information on service history and failure of the past transmissions? Cause?

Definitely recommend dropping the pan at the next engine oil change, or one year, to clean the pan and magnet(s). Adding extra magnets can really help keep the fluid clean.
To give you some history:

I bought the car for about 600$ at 120k miles. It was sitting for months at a gas station. The car was a NJ police car in a suburban area for at least 100k miles doing who knows what. At this time she had 3.27 gears.

A chick bought the car and ran it into the ground and the story is she got into a fender bender and ran up a bill at the mechanic shop that she left it at the shop because she didn't know what to do. I then bought it and the shop got their money and she got the car off her hands.

The car had so much cigarette ash on the floor it took a good 5-10 min with a shop vac to clean all the ash out. I had to take the seats out and wash all the upholstery at the laundromat and scrub the rubber floor but that's a different story. But hay, she did leave a nude photo (kinda hot too) in the glovebox, so that was good. Haha.

I then ran the car from 120k to about 225k and that transmission then failed but it got me home! Then the second transmission went from 225k to 410k. And again, the second transmission that failed still got me home with a passenger!

Both transmissions had pans with drain plugs. I used 2 magnets. I replaced all valves within the valve body with Sonnax upgrades and changed the filters more times then I can count. I also did the Jmod on both transmissions and kept the transmissions flushed with new Mercon V Super Tech fluid.

My driving is normal and conservative. No racing or abuse. I have the second transmission in storage and as soon as things slow down I will open it up and see what exactly failed and report back. I will also answer other questions on this post as soon as I get time.
 
Thanks for the info! Cool story, looking forward to the next episode. 😉

With your dedicated maintenance I'm surprised they don't last longer. Glad to hear that you've upped the fluid spec.
 
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