rear knock sensor replacement

**blowery901** · 10-05-2014

Anyone know an easy way to replace the rear knock sensor on a 2000 Grand Prix 3800 3.8L

**Fivefingerdeathpunch** · 10-05-2014

There isnt a easy way unless you take the motor or transmission out or drop or raise one of the two.

It can be changed in car but it's not easy, might help to have 4 hands instead of two. You'll have to get crafty with some tools to make them fit in there and you'll still need to torque them down to spec aswell.

**PurpleGuy** · 10-05-2014

Yea no easy way to change it in the car. I somehow got channel locks up in there to get it out. I don't remember really. It was like 3 years ago when I changed it. Anyway. It's not fun. And drain the coolant unless you want a bath.

**blowery901** · 10-05-2014

thanks i've been racking my brain and looking on google for a video never found one

**Scottydoggs** · 10-05-2014

its been done in the car. its just a pita a bit.

**Casper00693** · 04-19-2015

This is a must do for me... The only idea I had was to somehow remove belt housing bolts and split the tranny a tad to somehow slide the diff away a tad and get a socket up in there... Def no damn easy way, last time I looked I just shook my head and dropped a tear. :'(

**BillBoost37** · 04-21-2015

Crow foot

**J57ltr** · 05-08-2015

I realize this is a little old, but do your cars have a guard around the rear knock sensor? Mine is an 05'

Jeff

**timboku** · 05-08-2015

Originally Posted by J57ltr

I realize this is a little old, but do your cars have a guard around the rear knock sensor? Mine is an 05'

Jeff

Yup they do for the rear.

**J57ltr** · 05-08-2015

I'm finding that a 7/8" deep well a 3" wobble end extension and a 6" same work well. I used a coat hanger to unhook the clip.

**J57ltr** · 05-09-2015

Ok, so getting the rear O2 out of the block is a piece of cake it wasn't difficult. I used the tools mentioned and just backed it out. Super easy. Then I removed the bolts for the guard and moved it up so I could get the knock sensor out. Well as I'm sure you are aware the knock sensor is slightly larger than the area between the engine block and trans. I played Tetris for about 2 hours trying to get the thing out. I then realized that the bracket that connects between the engine and trans (pass side) only had 3-15mm bolts and seemed easy enough to remove. The first 2 bolts are pretty easy and came right out. The 3rd was a bear. Gearwrenches don't even have enough swing. I was able to use a stubby wrench to remove it.

Now the bracket won't come out. It acts like there is another bolt, but I don't see anything. If I can get this bracket out the sensor will slide right out. What am I missing?

Jeff

**Reptile** · 05-09-2015

So, you took the bolts that hold the end of the trans out, did you take the two that bolt the bracket to the block out?

Those are a MF'er to get....

**J57ltr** · 05-09-2015

I could see 3 bolts total I cannot see a forth.

**J57ltr** · 05-09-2015

One was in the bottom of the engine oil pan, one was a little higher and in the trans then the bear was way up there and the one I could only use a stubby combo on it, the other wrenches hit the subframe. The 3 are out but the bracket is stuck. I can move it at the bottom and pried on it a little but it feels like some other bolt I may be missing. I'll force it if needed, but I'm not trying to break anything either.

**J57ltr** · 05-09-2015

Found the fourth bolt removed it and then realized that you can just push the damn thing over the trans end on the passenger side and fish it out with a magnet. A lot of work for nothing, it's an easy job once you see how to do it. I'll do a write up.

Jeff