Thread: Rear KR Sensor causing me fits

OK, looking for some assistance. I CANNOT get to the rear O2 sensor. I have my oil pan pulled and I do not have room to get the 22mm socket between the edge of the block and the trans. Also, I can get a 22 mm wrench on it from the side, but then no ability to turn the wrench because of obstruction. I may try to grab a large ratcheting 22mm wrench, but not sure if I can get that in there because the ratcheting wrenches are thicker walled. Is there something I'm missing, or do you have to separate the trans from the motor to get this son of a ***** out?

Thanks in advance.

every time i look up at mine it looks like a socket and a extension to a ratchet would get it done. looks tight like your saying.

being that it needs to be torqued when re installed, id think the socket with a extension should fit.

Originally Posted by Scottydoggs

every time i look up at mine it looks like a socket and a extension to a ratchet would get it done. looks tight like your saying.

being that it needs to be torqued when re installed, id think the socket with a extension should fit.

So are you saying that you have done it? or that it looks like you can do it. I have repeatedly thought the same thing. A small socket would fit, but unfortunately the KR sensor is a 22mm socket which ends up being a wide ass socket. As far as torque, it's like 11 ft lbs or something pretty small.

Unbolt the motor mount and dog bones, then jack the motor up a few inches. I figure that should get you enough rooom to sneak in there.

Unless the trans moves with it, so hmm.

The trans is bolted to the motor so it'll move with it.

Lies, all of it.

I has an idea.


Get a crows foot that fits the knock sensor, might work.

Originally Posted by glendayle

So are you saying that you have done it? or that it looks like you can do it. I have repeatedly thought the same thing. A small socket would fit, but unfortunately the KR sensor is a 22mm socket which ends up being a wide ass socket. As far as torque, it's like 11 ft lbs or something pretty small.

i have not changed one, on a 3800, but that torque setting need to be dead on, or it dont work right. ( ive changed them on other cars) a deep 22 and 3/8 socket and extension certainly looks like it should fit up there.

Not to sound like an ass, but I'm really hoping that only people that have accomplished this task(or know that it is not possible to respond).

Originally Posted by Fivefingerdeathpunch

Unbolt the motor mount and dog bones, then jack the motor up a few inches. I figure that should get you enough rooom to sneak in there.

Unless the trans moves with it, so hmm.

Well, I've already removed my oil pan which means that the motor mount and dog bones are already off.
Trans is connected to the motor by the snout bracket, 4 or 5 bolts around the bell housing and 3 bolts from the flex plate to the torque converter. This is why part of my question was asking if I need to separate the motor and the trans.

Originally Posted by Fivefingerdeathpunch

Lies, all of it.

I has an idea.


Get a crows foot that fits the knock sensor, might work.

Plausible, I suppose, although I don't know that I have or would buy a 22mm crows foot.

Originally Posted by Scottydoggs

i have not changed one, on a 3800, but that torque setting need to be dead on, or it dont work right. ( ive changed them on other cars) a deep 22 and 3/8 socket and extension certainly looks like it should fit up there.

Yes, you are correct, it LOOKS like it should fit up there, but unless I'm just a mentally challenged person that has a hard time putting the round block in the round hole it doesn't. And as far as torque setting, it is important to be on, but if I have to "guess" I will gladly do it. I'm sure there is somewhat of a tolerance.

Swiggles and others have done it. Therefore it's very possible. Choose your tools and you'll be successful. I believe most say they do it with a 3/8" drive deep socket. The torque spec is 14ft lbs. Expect a bath when you pull it.

Alright Scotty, you have some vindication. I went and bought a deep well 22mm socket that was NOT an impact like the one I had and I was able to get it. It was a little bit on an angle and didn't grab the sensor great, but it was enough to get it out. Now I'm frustrated because I can't find the replacement. It's sitting around here somewhere playing hide and seek(and winning)

Yea I wasn't seeing what your issue was. I smashed mine putting the trans back in once and changed it. It was a 10 minute job. I put a 3/8ths drive socket on it from over the trans then snaked a extension up to the socket.

Originally Posted by Anthony Smith

Yea I wasn't seeing what your issue was. I smashed mine putting the trans back in once and changed it. It was a 10 minute job. I put a 3/8ths drive socket on it from over the trans then snaked a extension up to the socket.

You damn trans guys always be busting stuff up!