Steps for disassembling the car

Note: scroll down to see photos I took during this process. Sometimes I refer to a photo in the steps below, but it's at the very end of these steps instead of near the text.

1. Use your regular size ratchet and a 13mm socket to temporarily remove the 3 bolts from the passenger side bar that is over the battery. You technically just need to move this bar enough that you can access the negative battery post on the battery. Use a 10mm socket to remove the bolt securing the negative battery cable. If you are like me and have the interesting “lock” for that cable, pay attention to the way the polygonal pieces of metal are stacked once you have removed the nut and those two polygons. (Take a photo of it. Unscrew the screw and remove the triangles. Wiggle the bolt out from underneath the T-shaped piece. Slide the T-shaped piece out.) Lift the negative battery cable off the post, push it out of the way, and reassemble the lock and such but put it on your workbench out of harm’s way. You can reattach the bar with the 13mm bolts for now if you want, because you won’t need to remove it until you’re hooking the battery back up much later.

2. Remove both headlights. They are secured to the car by a black piece of metal with a single 10mm bolt in it. You remove that bolt, pull the metal piece upward, and then slide each light straight out toward yourself. If the metal piece won't slide upward, try wiggling a little or moving things a millimeter here and there. If it won't budge, spray it with some silicone lubricant and pry it with one of the plastic pry tools. A tiny bit of wiggling may be needed to slide the headlamps out, but they come straight forward. Once you have the headlamps slid out, you’ll need to detach the black and purple electrical connector. This connector is difficult the first time you ever encounter it, but it is so, so simple. Very close to where the wires enter the connector there is a square tab that you need to squeeze gently with your thumb to remove the headlamp. It will surprise you how simple it is once you squeeze the correct portion of it. The connector is impossible to remove without discovering that tab. After you’ve removed the headlamps and set them aside, you can replace the 10mm bolts and tighten them finger tight so you don't lose them.

3. You're almost ready to lift the car now. Make sure the transmission is in Park... set the parking brake with your left foot... and put some small wood blocks behind your rear tires. If you have a floor jack similar to mine, there is a boxed metal subframe under your GXP and you need to get the jack exactly centered on that before lifting. (Reference "jacking instructions" image). The shop manual warns about potential damage if you lift the car from here without being centered. You slide your low profile floor jack in perfectly centered from the front and get the saddle of the jack centered on that piece of silver colored metal. If you own a scissor jack you’ll have to refer to your car’s owner’s manual and lift behind the wheels on the specific jacking locations.

4. Our cars don’t have great locations for placing jackstands, but they are essential to safely suspending your car in the air. Ideally, you need to put them to where they can grab around something so the car is less likely to slip off. There’s a good weld on the box subframe that is good for this on both sides. I didn’t use it until my second time lifting the car so… look at what I circled on the photo instead of doing what I did. What I did made it possible for the car to slip off, so I left the jack under the front of the car for extra security, which isn't as ideal as doing it safely.

In case my photo doesn’t work someday… finding the driver’s side jackstand location is easy. It’s a big piece of metal welded onto the outer edge of the box frame very close to the transmission pan. The passenger side one is in the same location on the opposite side of the car.

5. Remove the front fender liner bolts (reference "front fender liner removal" photo) using a 7mm socket or 9/32 socket. You don’t need to remove the wheel if you use sockets, but you will if all you own is a socket driver in this small size. There are 9 of these bolts on each inner fender liner. The bolts are not absolutely identical. If you have the front passenger side wheel directly in front of you, the order from left to right is:

big washer, regular, regular, regular, regular, regular, shorter screw, big washer, big washer

The shorter screw goes onto the engine compartment (frame rail). The bigger washer ones are all mounted really low on the inner fenders in front and behind the tires.

6. Remove the four 7mm bolts on the bottom of the front bumper (reference "removal of retainers from lower front bumper" photo if you need to (you probably won't need to)). Remove the 6 pop fasteners using your plastic prying tool. (You can use a flathead screwdriver if you don't want to buy one of these... but these plastic prying tools are amazing, make the process so much easier, and don't bend/damage the pop fasteners like a screwdriver will...). You pry up the head of the plastic nail and then pop the entire fastener out of the hole with your fingers.

7. There are three very obvious 10mm screws holding the lower air deflector to the bottom of the car (reference "lower air deflector removal" photo). Remove those. Some people call this lower air deflector the “rock guard”. Note: I don't know why people complain about how hard it is to remove this, it's absolutely simple if you know the next step.

8. The final step to removing the lower air deflector is to slide it off the plastic bolt that prevents the deflector from falling off and landing on your face once you've removed the 3 screws in the previous step. It’s very simple (reference "lower air deflector removal" photo). Right in the center of the tip of the nose of the car there’s a square recession. In that recession (if you look up into it), is a plastic pop fastener that almost looks like it should glow in the dark (it’s whitish green). You don’t loosen this. You push the lower air deflector forward (away from the vehicle) and it’ll come off that ledge and start to fall on you. It doesn’t weigh much, so don’t worry.

9. Once you have it off that ledge, start at the wheel wells and kind of pull it off on both sides, then push it toward the vehicle from the front and it’ll fall right off.

10. The next step is removing the bulbs from the front bumper. Note: there’s absolutely no reason to remove your grills, turn signal light housings, or foglight housings. Don’t waste your time or potentially break the plastic tabs off! From underneath the car, you can twist the bulbs for the foglights and turn signals out of their light housings. (Reference "foglight light bulb removal" image if you need to). You simply turn them about a 45 degree counter-clockwise turn and pull them straight out. (Note: if you’re like me, you’re going to replace these bulbs before putting your car back together. Mine are from 2006 and I’ve never had to change them before, so it's a great time to finally change them.)

11. Stop and look at the front bumper removal image so you're aware of what's coming up. (Reference "front bumper removal")

12. Now we’ll remove the bumper. There's an order you’re supposed to remove the bolts that hold the front bumper on. I'd say the order of steps 1 and 4 are very important, and not the typical order a person would do the task. The first bolt is a 10mm one in the wheel well. Use a ratchet. The second ones are the 5 plastic pop fasteners by the hood latch (above the Pontiac nose emblem), which are easily removed with the plastic prying tool. Third are bolts on the bottom (but they are already gone because we removed the lower air deflector already). Four are the last two bolts and they are really close to the outer edges of the headlights. The one on the passenger side is harder to remove because the windshield washer fluid tank gets in the way of a ratchet if you only own deep sockets like me. I used an articulated socket on my ratchet so I could use it at an odd angle. I then used a 10mm socket driver to fully remove the screw. Remove the passenger side one first since it'll be more difficult. Get a helper if you're nervous. The bumper pulls straight out. You can either have a friend or spouse help you hold one side, or you can stand in the center and pull it straight out and toward yourself and carry it carefully. You’ll need to unthread the wiring looms for the foglights from the styrafoam on the back of the bumper before you can walk away with the bumper. It’s really simple to detach them; unwind the wires from the styrafoam. Keep in mind that the polyurethane plastic bumper is more flexible than the paint. You don’t want to flex it too much. Be gentle when carrying the bumper. Instead of setting it on the concrete, you can throw some disassembled cardboard boxes or rugs under it. Or just go set it in the grass.

13. You can remove the 2 small plastic pop fasteners holding the plastic panel around the hood latch. That piece didn’t get in the way particularly, but it’s so easy to remove that you might as well do it just in case you need to put your light up there to see what you're working on later.

You now have a really good opportunity to wash these parts if you feel like it. You’re probably covered with random black soot by now and road debris. Wash these parts now and you won’t be as dirty when you put it all back together tomorrow. If you decide to wash everything, put masking tape over the holes for the turn signals and foglights so you don’t get water in their housings. I had to use a hair dryer to get the water out. Don’t hose off your car… just the pieces you’ve removed. I used car washing soap, a bucket, a rag, and a garden hose.

Also, note, for our cars, DO NOT mess with the fins on the radiator or condenser too much. The recommended way of cleaning them is with compressed air. You can use a shop vac to vacuum them off instead if you want. I had grasshopper parts stuck in mine...

Steps for mounting the transmission cooler

Keep in mind… the location we mounted this was NOT without compromises. This cooler is very large and all solutions will involve compromises. I had to modify the plastic lower air deflector (rock guard) because of how low we mounted this. If you mount it significantly higher, you’ll have to modify the upper air deflector and possibly other things instead. Had I known I’d have to have hoses hanging beneath the car, we would have investigated if we could have mounted the cooler higher, but it would have involved a lot more fabrication if we had. Note: It’s not a good idea to cut or notch metal pieces of the car, because if GM could have saved some money and weight, they would have. Your hood latch may not latch properly over time or some other issue might develop if you cut, notch, or remove any of the structural metal from the chassis. Modify plastic when possible because it isn't structural. We chose the location we did because it provided a great place to support the weight of the cooler and (as an added bonus) it hid half of the cooler behind the crash bar, which (I assume) has reduced its cooling ability a bit (people have said that they haven’t seen temperatures higher than 150 degrees with this cooler, so pushing that a little higher is NOT a bad thing. 170 or 180 degrees is a really good operating temperature for a transmission. You want the fluid to get hot every so often.)

1. Wait for your transmission cooler to arrive at your house. Go to Home Depot and the auto parts stores to get the supplies you’ll need. You don’t absolutely have to replace the bulbs, but I think it would be foolish to go through all this work and leave 15 year old bulbs in the sockets since they are so difficult to change with the bumper attached to the car. Note: some people (including myself) might be concerned about mounting a big silver radiator-lookin’ thing behind their bumper. Will it look awful? Should I paint it black first? Well, keep in mind that your A/C condenser and radiator are silver and they never bothered you before, right? The cooler will be nearly invisible, so don’t paint it. It also won’t work very well if it’s painted. You won't be able to see it unless you're looking for it really hard.

2. Remove your transmission cooler from the box and use masking tape to hold the LVP floor sample to the center of it. You’ll want this on there for two reasons. One, it’s going to create the empty space we desire for the cooler to have when it is mounted—you don’t want it resting on some other piece of metal. Two, it’s going to protect the fins a little bit while you’re test fitting it. You can also measure and mark the center of the bottom of the cooler if you want to with a Sharpie.

3. To make your life easier, remove the upper air deflector from the car right now. It’s a black plastic piece held on by the off-white pop fastener that held the lower air deflector from falling on your face. (Reference the "upper air deflector removal" photo). That off-white pop fastener removes just like the black ones you removed earlier. The upper air deflector also has two sacrificial black plastic fasteners in the upper radiator area you’ll need to remove. You can’t really reuse these fasteners because they will get damaged when you pry them out, so hopefully you bought the Dorman ones from O’Reillys I mentioned earlier. Use your plastic prying tools to remove these sacrificial black fasteners. You'll need to remove the ambient temperature sensor next, which easily pops out. (Reference the "ambient air temperature sensor removal").

4. We didn’t do this until later, but you get to learn from our process. Go ahead and mark the piece of flat aluminum bar you purchased at Home Depot to just cover the distance of the top mounting brackets on the transmission cooler. Saw off the excess and file it a bit smooth so you don’t cut yourself later. Mark the drilling locations on that bar and go ahead and drill them. Don’t attach it yet. I think it was 30.75 inches long once cut. You’ll end up using the screws and nuts that came with the Tru-Cool cooler, but you might want to hold off on doing that for now.

5. Put masking tape on your lower radiator core support. It’s hard to get a pen or Sharpie to stick to painted metal. You’ll be marking the holes you’ll need to drill in your radiator support based on the location of the brackets. We found the cooler to be best mounted slightly off-center. I can’t recall off the top of my head why it wouldn’t have mounted well centered, but it was a lot better for some reason being mounted perhaps 1 to 2 inches toward the driver’s side. If you decide to use a level, make sure your car is level first and/or make the cooler equally unlevel to match how unlevel your car is jacked up in the air.

6. Drill your holes. It’s easier (and more precise) if you start out with your 2^nd smallest bit to poke/dent the metal and then make the hole, pick a midrange size bit and make the hole bigger, and then use your 1/4 inch bit to finish the hole off.

7. Test fit that your holes are in the right places (they better be!). Take your 2 inch Grade 8 hex cap screws and all of the Nylon spacers and see if it mocks up properly.

8. If everything is good, you need to take the cooler down now. Take those Grade 8 hex cap screws and work them into the lower radiator support from the inside to the out of the holes you drilled. It was difficult to do this, but it was worth it. We put a piece of masking tape on the screws and used pliers to guide the screws through the holes. I pushed upward on the radiator while my dad threaded the screws through the holes to create a little more room for the screws to be pushed from the inside.

9. Once that is completed, put your 1 inch and 1/4 inch spacers on. Put the transmission cooler back into position. Put on your Grade 8 locking washers and Grade 8 hex nuts. They only need to be finger tight right now. The direction of the lock washers does not matter.

10. The best way to mount the top of the cooler is by using the piece of flat aluminum bar I mentioned you should cut and drill earlier. Screw this onto the cooler’s mounting brackets. You’ll be mounting to the center support piece. Try to figure out where you’ll need to drill the center support piece (make sure you won’t be damaging that electrical connector that is very close to where you’ll be drilling). You’ll need to put the upper air deflector back in here 1 or 2 times to make sure it still fits. Note: if you are mounting the cooler identically to the way we did it, you won’t have to modify this upper air deflector, which was a surprise for us. If you are mounting it higher than we did… there’s no way you’re going to get this thing to fit back where it goes unless you modify it somehow.

11. We utilized one of the steel pieces of mounting hardware the Tru-Cool cooler came with. We bent it 90 degrees directly on the center of the 5^th hole in it and cut it just after the 6^th hole. We bent it with two pairs of Vice Grips. Do what you have to do to get a good 90 degree bend.

12. We drilled 2 holes in the aluminum bar and mounted the 90 degree L-bracket we made to it using 2 hex cap screws and hex nuts from the Tru-Cool hardware. We used one of the shorter Grade 8 hex cap screws, a Grade 8 lock washer, and Grade 8 hex nut for mounting to the center support piece. If we had enough hardware to use all Grade 8 stuff, we would have, but we didn’t know we’d need so many and didn't buy enough extras.

13. You can now remove your LVP floor sample and check and make sure you still have a good gap. Make sure your upper air deflector still fits. Tighten everything up, but don’t reinstall the upper air deflector yet, just in case it gets in your way. It’ll be very easy to put on later.

14. Unless you need to put the car back together (because you need to drive it before finishing the job)... Install the barbed fittings that came with the Tru-Cool kit to the cooler. We used Vaseline on the outer threads to lubricate them before being fitted. Not sure if that’s recommended or not. Follow Tru-Cool’s instructions they provided in the box.

Steps for plumbing the transmission cooler

1. The OEM transmission cooler line going into the upper part of the radiator is easiest to remove first. On a GXP, it is on the driver’s side and very obvious at the top of the radiator. There’s a little plastic piece you twist off. Then you have to remove the Quick Connect Fitting (reference "Quick Connect Fitting removal" image). You use the dental pick to grab and rotate the retaining ring/clip. It's actually quite difficult, but it'll fly off eventually.

2. You don’t need to care about whether you lose the retaining ring, because you won’t be reusing it.

3. Position your drain pan underneath and pull the cooler line straight out of the fitting. If you haven’t driven your car very recently, you might only lose a few drops at this point. Note: You do not need to remove the actual fitting from the radiator at all! If you decide to... Do not remove the upper and lower transmission cooler fittings from the radiator at the same time otherwise the OEM transmission oil cooler will fall inside the radiator end tank. (Reference "transmission cooler lines" image if you want to see how these connect to the radiator. Note: this image is of the radiator in a V6 Grand Prix. In a GXP, the transmission cooler lines enter the radiator on the driver's side, not passenger side).

4. In order to do the lower one, you’ll need to turn your steering wheel all the way to the left or remove the wheel in order to get your head inside the wheel well where you can see what you're doing. Turning the steering wheel works just fine. Inside the driver’s side wheel well there is a plastic splash shield held on with 3 plastic pop fasteners with phillips head screws in them. (Reference "splash shield removal" image if necessary). Loosen those with a screwdriver. If they have difficulty coming out, use your plastic tool for removing these and push away on the plastic portion while you unscrew the screw or pry upward on the screw while you’re twisting it. These can be annoying and not come out very easily, but you’ll get the hang of it.

5. Set that panel aside. Get a flashlight. You should now be able to see the lower transmission cooler line on the radiator. Remove the quick connect retaining ring. Position your pan underneath. Pull the cooler line straight out. You should lose at least 1 cup (or more) of fluid and it will continue to drip for quite a while. (Note: like most people, we didn't plug the Quick Connect Fittings on the radiator, so every time I drove the car for a few days, a bit of transmission fluid would leak out of the OEM transmission oil cooler inside the radiator. This is no big deal. Put a flattened cardboard box under the front of your car in your garage and just let it leak out till it stops.)

6. Note: you may want to plumb the car differently from how my dad and I did it. The way we did it used the least amount of new parts, but did come with its own compromises. If you prefer to complicate your life (or if your existing transmission lines are corroded and unusable), I've provided a list of Possible Alternative Parts you might want to use further down this page).

7. You’ll now need to make sure the lower air deflector (rock guard) fits. It won’t fit if you mounted your cooler exactly like we did. You’ll need to make a notch for each of the 2 nylon pieces and make two 50-cent piece coin-size holes in the lower air deflector for the cooler's barbed fittings to go through. You can make these easily using a hair dryer to soften the plastic and a utility knife. The hairdryer makes the process easier, but is not required.

8. You’ll need to hang the lower air deflector from that glow-in-the-dark looking plastic bolt while you work on plumbing it so make sure things still fit.

9. Like I said above, you may want to come up with your own plan, but what we did worked after some effort. You can reuse the stock transmission cooler lines (like we did) and connect your hoses directly to those lines. Or… you could remove the lines and plumb directly to the transmission. Or… you could cut the rubber portion of the stock transmission lines and use additional double-sided barbed fittings (similar to a hose repair kit). Or… you could remove the crimp connections and reuse the barbed fittings underneath those supposedly with some screw clamps. There are a lot of options, so choose your own adventure. I only know how to do what we did. Originally, I was going to go the -6AN fitting route, but it seemed like more trouble than it was worth, and so I returned almost $200 in AN parts to Amazon that I had purchased in case I needed them. The parts and hose with the Tru-Cool kit were high quality enough in my opinion. I discussed these parts below in a section called Possible Alternative Parts.

10. If you’re doing it like us, you’ll need to remove the piece of metal holding the two transmission lines together (reference "transmission cooler lines" image). Then adjust the upper transmission cooler line to be underneath the car by gently moving it. It can be positioned near the driver’s side tire area without much trouble. Move the lower line to be closer to the center of the car.

11. Get your 23/64 hose from the Tru-Cool kit. It should be plenty for the install if you’re copying us. You’ll actually have 6 inches leftover if you copy us. (Note: unless you are plumbing an inline cooler or a bypass, it doesn't matter which hose goes where if you're plumbing your cooler in a standalone configuration. In other words... you don't need to know the direction of the flow.) Thread the screw clamps onto the hose. This hose will be very tight, so it works great. Because it is so tight, it will be helpful to lubricate the inside of it with some of the transmission fluid from the pan and heat the end of the hose with your hair dryer for a dozen seconds or more. It’ll be less of a struggle to get it on the flares of the cooler lines you pulled out of the radiator earlier if you lubricate and heat the hose up a bit. It's still going to take a lot of strength, so get ready to grunt and sweat. Use a single screw clamp on each connection. Tight, but not so tight that it digs into the hose.

12. If you are copying us, you’ll thread the passenger side hose through one of the existing holes in the lower air deflector.

13. Reattach that metal piece that was holding the cooler lines together to the radiator/fan shroud if you can/want to. My dad said he reused it, but I don't think so. I haven't removed the lower air deflector and checked, but I'm pretty sure that piece is sitting in my toolbox....

14. Attach the lower air deflector to the car.

15. Ziptie the driver’s side hose to the lower air deflector to give it some support. Make sure you don't bend a hose too much. You need gentle arcs. If you bend a hose too much, it could kink, and goodbye transmission.

16. I added 10 oz of transmission fluid. It’s difficult to know exactly how much to add, so try to guess based on how much you lost, plus add a little more than that since you’re now having to fill a few extra feet of hose. I was at 21,000 miles since my last transmission fluid and filter change, so I didn’t care too much about being at the exact proper level. I was scheduled to get my fluid and filter changed in two days anyway.

17. Temporarily ziptie the foglights together and rest them on top of the lower air deflector to prevent them from falling and getting damaged while you drive. Test drive the car if you can safely do so in your neighborhood before putting it completely back together. Keep in mind that if you’re driving through standing water or puddles, it’s going to get into places it shouldn’t because your inner fender liners are removed.

18. If you’re like me, you’ll hear some gurgling as it gets rid of air. Take it easy. If your car is slamming into gears, use your best judgment. Mine was driving flawlessly. I drove around the neighborhood for multiple laps and it got up to 140 degrees. Make sure to sit in reverse a while, neutral, park, drive, and manual mode. You want to test everything. (You don’t need to drive in reverse, just sit there with your foot on the brake for around 30 seconds while in gear. You could drive a few feet in reverse if you want, but nothing crazy).

19. Take it home and visually inspect whether your connections are leaking while the car is running. We didn't have any leaks. Check the fluid level while the car is running. I was a little low and added (I think) the rest of the quart, or just around 6 or 8 oz. Put your car back on jackstands and go take a break while the engine cools off for a while.

20. Replace your light bulbs while your hands are clean. Put the splash shield back on in the wheel well next. Put the car back together in the opposite order of how you took it apart. It should go back together even easier than it came apart. These screws all technically have torque values, but they are all pretty easy to figure out manually. None of them take very much torque at all. You’ll need someone to hold the other side of the front bumper while you reattach the other side, or you could stack up cardboard boxes to hold it up for you while you slide it in.

21. After putting the car back together, we used some zipties to add some support for the driver's side hose. Like I mentioned above, I have purchased some 5/8 Inch rubber cushioned clamps. I'll update this site if the size is correct and with new photos once I've used them.