My transmission recently went inop due to codes P1757 and P1759 indicating a bad front brake solenoid. I ordered the replacement solenoid, but after doing some more research I found out that the solenoid itself usually doesnt fail. The problem is usually a broken contact inside the TCM, which provides power to the solenoid. On 2003 and early 2004 models, the TCM is located inside the cabin in the passenger side kick panel. But on late 2004 and up models it is attached to the top side of the valve body, so removing it is a much messier process. My car is a 2005 coupe, so I had to get messy!

This whole process is much easier to do if you have someone else to assist you because the valve body is a bit on the heavy side. Trying to hold it up with one hand while removing bolts and unplugging wires with the other is kinda difficult. It will probably help if your car is on a lift, but I dont have access to one so I had to lift the car up on jackstands about a foot and a half off the ground. More clearance is better!! You also don't want the transmission to be hot. So let the car cool off for a while before starting this job.

First, you will need to drain the oil from the transmission pan. I don't have a pic but its the big plug located at the bottom of the pan...you cant miss it. Expect to drain about 5 quarts of fluid. You can reuse it again if its clean. Once all the fluid is drained, reinstall the drain plug so you dont lose it.
Then remove all the bolts holding the pan on...22 bolts total. Move the 02 sensor wire brackets out of the way.



Now you will see the valve body assembly. Unplug the 2 connectors and move them out of the way. There are only 12 bolts u will need to remove to drop the valve body. I have circled them and labelled them long and short. There is a guide bolt which has a slightly fatter shank than the rest of the bolts. Remove the guide bolt last. This is where having a helper will come in handy. After removing the guide bolt, u need to support the weight of the valve body while u unplug the harness from the car.




Now we need to remove the TCM from the valve body. First, remove the 7 allen bolts for the solenoids and pull the solenoids off. Keep them in order so you know which one goes where. Then remove the bolts holding the TCM onto the valve body. (10 allen bolts and 1 regular hex bolt). Unplug the harnesses and pull the TCM off.





Now we need to open up the casing for the TCM. I just used two thin flathead screwdrivers to slowly go all around and pry open the edges. Go slowly and be careful not to break the tabs off. There are 3 or 4 tabs located towards the center of the case as well. Just keep slowly prying and pulling til u get the case to fully open.






Once fully open, go ahead and inspect the contact for the front brake solenoid. It is the one in the very middle. Here is mine and you can see that its broken. If you inspect yours and dont find a broken connection, then maybe your front brake solenoid actually did fail. Just go ahead and replace it I guess. But if its broken...lets fix it! You can pull up on the contacts to lift them up out of their slot...just to make it easier to work with.






What we need to do is solder it. But the solder doesnt stick at all to the metal because of the silver coating on the metal. You need to lightly sand off the top silver coating until the copper color underneath is exposed. U can use a small file or some fine sandpaper. I used my dremel with a fine grinding bit on the tip. Anyway, remove the silver coating off of the areas you are going to solder. Then the solder will stick to it really well.









I soldered mine and even added a few strands of copper wire on top of the whole thing. Thats just in case the solder ever does break at the same point, at least power can still flow through the wire to the solenoid. Dont make your solder repair too bulky or you wont be able to push the contact back down into its slot or snap the TCM casing back on. And obviously, make sure the solder isnt touching the contact next to it.


And that should be it! Snap the TCM cover back on. Install it back onto the valve body. Plug all the wiring back onto the TCM. Reinstall the solenoids. Reinstall the valve body back onto the car. Note: Install the Guide Bolt first when installing the valve body back onto the car. This will align all the fluid passages correctly. Then go ahead and install the remaining bolts. Also, don't forget to plug in the TCM harness to the car before installing the valve body. Lastly, careful not to pinch any wiring on top of the valve body during installation.

Ok, go ahead and plug the wires back in. Reinstall the oil pan. I used a little bit of RTV around the edges just for reassurance, but I don't think you have to. Do not overtorque the bolts or you will mess up the gasket. Dont forget the brackets for the O2 wires. Refill your transmission fluid using a funnel, through the dipstick tube. Start the car, make sure E-brake is on, hold the brake pedal as well for extra safety, cycle through P,R,N,D gears a few times, give it a couple good revs in park, check for any leaks from the pan. If all is well, go for a test drive!

I also wanna give credit where it is due. I found out about the broken contact issue from watching this video. This guy does a great job at troubleshooting and looks like he knows his stuff pretty well. I would recommend watching his video as well before trying this repair.

 

Great write up! Glad you were able to solve the problem.
One thing I think is weird is the transmission pan bolts have RTV on the threads from the factory. I put a dab on my bolts when I reinstalled the pan on my 04 G.

 

You’re a life saver, we got everything done except we removed one too many bolts.. realized that once I read up on your post. Now we have a bunch of loose bolts and I was wondering if you know which ones are specifically for installing the valve body back in its case? I know some have numbers or letters on the head..

 

Here you go, FSM section AT - Automatic Transmission.

 

Thank you for the info. It was very helpful.