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How to Replace Catalytic Converters 00-06 Chevy Suburban 1500

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  1. step : Removing the Catalytic Converters (0:50)
    • Disconnect all four O2 sensor wiring connectors
    • Move the O2 sensors aside to allow you space to remove the catalytic converter
    • Remove the three 15mm nuts from the front driver side exhaust flange
    • Remove the three 15mm nuts from the front passenger side exhaust flange
    • Remove the two 15mm nuts from the rear flange
    • Separate the catalytic converter from the tailpipe with a pry bar
    • Place a block of wood under the transfer case
    • Support the transmission with a jack
    • Remove the four 21mm bolts from the transmission cross member
    • Remove the two 15mm nuts that hold the cross member to the transmission mount
    • Remove the transmission cross member
    • If you are not reusing your catalytic converters, leave the cross member in place and cut the catalytic converters with a reciprocating saw
    • Pull the catalytic converters down and off the vehicle
  2. step : Transferring the O2 Sensors to the New Catalytic Converters (6:33)
    • Remove the O2 sensors from the old catalytic converters with a 22mm wrench
    • Install the O2 sensors into their respective positions in the new catalytic converters
  3. step : Removing the Transmission Cross Member (8:21)
    • If you did not remove the cross member before removing the catalytic converter, do so now
    • Place a block of wood under the transfer case
    • Support the transmission with a jack
    • Remove the four 21mm bolts from the transmission cross member
    • Remove the two 15mm nuts that hold the cross member to the transmission mount
    • Remove the transmission cross member
  4. step : Installing the Catalytic Converter (9:37)
    • Lift the passenger side catalytic converter into place
    • Remove the gasket from the exhaust with a flat blade screwdriver
    • Line up the new gasket with the exhaust manifold
    • Fasten the three 15mm nuts onto the passenger side exhaust studs
    • Lift the driver side catalytic converter into place
    • Line up the driver side catalytic converter where it connects to the passenger side catalytic converter
    • Fasten the three 15mm nuts onto the driver side exhaust studs
  5. step : Installing the Cross Member (11:06)
    • Lift the cross member into place
    • Support the cross member with a jack
    • Fasten the two 15mm nuts that hold the cross member to the transmission mount
    • Fasten the four 21mm bolts into the cross member
  6. step : Connecting the Catalytic Converter (12:48)
    • Fit the catalytic converter flange to the tailpipe flange
    • Install the 15mm nuts onto the exhaust studs
    • Replace the studs with bolts if necessary
    • Install the exhaust clamp around the slip joint
    • Fasten the two 14mm nuts onto the exhaust clamp
    • Thread the O2 sensor wires away from moving parts
    • Connect the O2 sensor wiring connectors
  7. step : Checking the Exhaust (15:26)
    • Start the engine
    • Listen for exhaust leaks
    • Clear the check engine light with a scan tool
    • If no scan tool is available, disconnect the battery for an hour to reset the codes

Hi, I'm Mike from 1A Auto. We've been selling auto parts for over 30 years. We're dedicated to delivering quality auto parts, expert customer service, fast and free shipping, all backed by our 100% satisfaction guarantee. Visit us at, your trusted source for quality auto parts.

In this video, we're going to be working with our 2002 Chevy Suburban. We're going to show you how to remove and replace the catalytic converters. If you like this video, please click subscribe. We have a ton more information on this and many other vehicles and if you need these parts for your car, you can follow the link down in the description over at Here are the items you'll need for this repair.

Disconnect all of your O2 sensors. Out look pretty rusty so we're going to disconnect them and try to remove them once the cats are out of the truck. Your driver's side upstream O2 connector is located on the side of the transmission just above the range selector. Pull out the blue safety tab, lift up on the rear half of the connectors tab, and disconnect it. Then pull your wire over the drive shaft and allow it to hang. The downstream O2 on the driver's side is plugged in right on top of the cross member. Ours is actually popped out of its clip. Same thing. Remove the tab, lift up, separate the connector, and hang your harness out of the way. The passenger upstream is located just behind the front body mount on the cab of the vehicle. We'll have to separate this connector. Just pinch it and pull it through the hole. Unplug it, pull it over the frame. Allow that to hang as well. Downstream is located on this cross support under the cab just before the coupling here at the Y pipe. Disconnect it and I'm going to pull it over the cross member to let it hang since our exhaust is going to come out that way and we don't want it to get caught on anything.

Remove the three 15 millimeter nuts going through the exhaust flange. These are on studs so the stud may come out with the nut and that's perfectly fine. You're going to need a 15 millimeter socket, some extensions, and a ratchet to remove them and you'll need a universal joint to get the one on the top.

If these are being stubborn, you can use penetrating oil or heat to get them off. Another good method for removing them is to wiggle them back and forth. It’s better to do that with a breaker bar and just kind of work it left and right and left and right to free it up. It takes a while but it's certainly easier than breaking a bold and needing to replace it.

Remove the same three 15 millimeter nuts on the passenger's side flange. This is a perfect example of one coming out with the stud. Again, that's perfectly fine. Just make sure that this goes back in the same hole it came out of.

Using the 15 millimeter socket ratchet and extension, we'll remove the two 15 millimeter nuts on the flange. Yours if it hasn't been worked on before should have two 15 millimeter nuts with studs. However, ours has had a pipe replaced and the stud broke, so it's through-bolted. That's perfectly fine. We're just going to need to hold the head with either a 15 millimeter wrench or I'm going to use a breaker bar and socket because it's kind of deep in there and hard to get a wrench on.

We need a pry bar to separate this because the bolt that was put in there is a little longer than the factory stud would be. If yours has factory hardware it should come right off. We're replacing our catalytic converters. To get the one out, we're just going to cut it since we're replacing it with a newer style piece anyway. However if you're removing this and planning to reinstall this or similar style exhaust piece, you'll need to remove the four transmission cross member bolts, after supporting the transmission with the floor jack or screw jack. Remove the four transmission cross member bolts and the two bolts that secure the transmission mount to the cross member so you can drop this bar down and out and remove your exhaust.

Whenever using power tools like a reciprocating saw like we're using here – you can also get away with using a hand saw, a tailpipe cutter, or a cutoff wheel for this – , be sure to wear the proper safety equipment like glasses and never cut towards yourself. Make sure we're nowhere near the O2 sensor.

Here we have our old catalytic converter set up that we cut out of our vehicle and our new parts from As you can see, these parts in size and shape are very much the same. However, the actual layout of the parts is a little bit different. It also comes with a nice new set of gaskets which is going to make sure that the new parts seal up nicely and sound just like factory while providing the proper emissions outputs from the new cats here which is why we replaced our old ones. They'd gone bad and were causing a check engine light, making it so we couldn't get an inspection sticker.

All of the O2 sensory bungs are in the same location. We'll need to remove our old ones and install them into the new catalytic converters. Otherwise, these new parts from 1A Auto will go in, direct fit, just like our original equipment, get our vehicle's emissions back where they need to be by law, get our inspection sticker on there and fix you up right.

Using a 22 millimeter wrench, go ahead and remove your oxygen sensor. Just for the sake of consistency, this isn't a necessity, but I'm going to replace all of the sensors exactly where they came out of on the old pipe so this one is the upstream for the passenger's side so I'll reinstall it in the upstream of our new passenger side pipe and what I mean when I say upstream is that it is above the catalytic converter as far as the flow of exhaust is concerned, meaning the exhaust will come from the manifold, hit this sensor, go through our catalytic converter, and then go to our downstream O2 sensor behind the cat. These two sensors are used to check the efficiency of the cat because we know what kind of gases and how much are in the exhaust from this sensor and this sensor confirms that the catalytic converter is breaking them down correctly.

This is also why it's very important to make sure you properly diagnose cat related codes before just replacing the cats. For example, a PO420 catalyst inefficiency code is often just given a cat converter and can be caused by malfunctioning O2 sensors, cracks and leaks in the exhaust system, bad gaskets or other underlying issues that make the vehicle think it has an inefficient cat when in reality another component is at fault.

Now we'll use this process to replace all of our remaining O2 sensors from the old exhaust system and install it into our new one.

Unfortunately, we are going to need to remove the cross member. Rather than try to get a screw jack or a floor jack on here, we're going to take a piece of wood and tap it underneath the transfer case and over the cross member for the torsion bars. This will help keep everything supported where it is while we remove our cross member.

Reaching through the access hole in your transmission cross member, remove the two 15 millimeter nuts securing the transmission mount to the cross member with a 15 millimeter socket ratchet and extension. Using a 21 millimeter wrench socket and breaker bar, loosen and then remove all four of the bolts and nuts securing the transmission cross member to the truck. We've removed three out of four bolts and loosened the last one and now we can pull our cross member down into the side so we're going to take a second to see if we can't fit our exhaust in like this. Otherwise, we'll remove the fourth bolt in the cross member.

We'll install our passenger's side exhaust. Reach over the frame with a small flat blade screwdriver and make sure you remove the old exhaust gasket from the manifold on the passenger’s side. The driver's side is a little bit different. To install the new gasket, simply line up the tabs inside of the exhaust manifold, line up the flange and the plate. Reinstall your hardware whether it be that the nuts came off or the studs came out, just make sure everything goes back right where it came from and then tighten all of this hardware down with a 15 millimeter socket ratchet and extension.

Install your new gasket on to the exhaust flange followed by a new pipe. Make sure you're lining up the other end into the slide joint at the same time and start all three of your 15 millimeter nuts by hand. Tighten down your hardware with a 15 millimeter socket ratchet and extension.

Reinstall the cross member. We'll start by installing the two 15 millimeter nuts in the center to make sure that everything stays in place while we line up and tighten the rest of the cross beam. You should be able to see the marks from where the washers used to sit. Be sure to realign those when you go back together. Using a screw jack or a floor jack if you're doing this at home on the ground, lift up on the lowered side of the cross member. It should make it nice and easy for you to bring it up and align the holes so you can reinstall all three of your 21 millimeter bolts.

Because our exhaust has already been installed, we'll need to put this bolt through in the opposite direction, which is perfectly fine. It's just a matter of clearance and it looks as though this cross member may have been out before. We'll then reinstall our two 21 millimeter bolts on the opposite side. Start the nuts and then tighten everything down with your 21 millimeter socket ratchet and wrench. Remove your jack or screw jack. With the cross member back in, you can now reinstall your two 15 millimeter nuts on the transmission mount.

There's no gasket in the rear exhaust flange here. This is what's called the ball and socket style fitting so it actually seals itself metal to metal just fine. You're going to need two bolts here. I just grabbed two that I had lying around the shop so we'll be tightening them down with a 17 millimeter wrench and a 15 millimeter socket ratchet and extension. However, the hardware you find or use may vary.

Install the exhaust clamp around the slip joint. Make sure you put it right about in the middle – too far to either edge and it's possible that you could miss and just end up crushing the pipe and squeezing it off, which will create leaks and other issues. It doesn't really matter where you set this as long as you have easy access to it. We'll set it here at about the nine o'clock position.

The key to making a good clamp with these again is that it's centered and that you tighten down both sides evenly on this particular one. It's going to be a 14 millimeter socket and ratchet. I’m going to make a few turns on one side and a few on the other, back and forth until it's down all the way tight.

Make sure that the upstream O2 sensor on the driver's side passes over the drive shaft and not under it. Otherwise it'll get wrapped up and ripped off. Reconnect the connector up at the side of the transmission. Put the blue safety cap back in. We'll then do the driver's downstream over the transmission cross member. Send the passenger upstream over the frame rail, behind the body mount, and reconnect that. Then the passenger's side downstream also right over the frame rail.

Now we're going to start our vehicle and make sure that we don't hear any exhaust leaks. If your check engine light is on, you can either clear it with a scan tool, have a local shop do it with a scan tool, or if you don't want to go through that trouble, you can disconnect your battery and let it sit for about an hour and it should reset the codes in most vehicles. Our exhaust is nice and quiet, nice and smooth. We don't hear any hissing or rasping from a loose connection somewhere so our vehicle is all good to go.

Thanks for watching. Visit us at for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    General Tools

  • Jack Stands
  • Hammer
  • Reciprocating Saw
  • Floor Jack

  • Materials, Fluids, and Supplies

  • Safety Glasses
  • Block of Wood

  • Ratchets & Related

  • Swivel
  • Ratchet
  • Torque Wrench
  • Socket Driver
  • Socket Extensions
  • 1/2 Inch Breaker Bar

  • Screwdrivers & Related

  • Pry Bar
  • Flat Blade Screwdriver

  • Sockets - Metric

  • Complete Metric Socket Set

  • Wrenches - Metric

  • Complete Metric Wrench Set

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2002 - 2006  GMC  Sierra 1500
2003 - 2006  GMC  Sierra 1500
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2005 - 2006  Chevrolet  Silverado 1500
2002 - 2006  Chevrolet  Silverado 1500
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2007 - 2007  Chevrolet  Silverado 1500 Classic
2007 - 2007  GMC  Sierra 1500 Classic

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