I installed the T-Max a few weeks ago and I had a problem removing the rear o2 sensor on my 06 WG. I thought that it was cross threaded, because when I finally got the sensor out, 2 threads were just gone. Luckily the bungs seem to made of harder material than the o2 sensors. I chased the threads with a spark plug tap that I got at the local NAPA store and the new wide band sensors went in just fine ( with lots of anti seize applied to the threads.) There are several posts reporting problems when trying remove o2 sensors. But that should not be such a surprise, look at how many people have a tough time trying to remove the axles because HD applied little or no anti seize to them during assembly.

Good luck with it.
Arcane

 

When I was installing my V&H 2 into 1 big radius pipes , the first thing I did was spray WD-40 on the o2 sensors aft the removal of the stock pipes. I set them off to the side and continued with the install. By the time I got to that part mine came right out with little effort , I guess I was lucky.

 

^^^^^
Like he says!
This is not uncommon to happen!

I recomend soaking in WD 40 at the base of the sensor and let it soak for a few minutes, then using the correct 02 sensor socket, pull it slightly tighter about an 1/8 of a turn first, then work it back the other way and adding a squirt of WD every turn or two till shes unbound and out of the pipe.

 

Tap size is 21/32 standard 02 thread size.