I put an ez locker in the d30 front axle on my 89 YJ. In 2wd, I cant feel it or hear it. no problems even driving on highway. I went off road, (I have the rock lock cable replacement for the vacuum disconnect) tried to climb a hill in 2wd, no luck. SO I pulled the 4wd stick but left the rock lock off--this gives me 3wd, no luck climbing the dirt hill. engaged the rock lock which engages the other half of the front axle so all 4 wheels pulling and climbed the hill without spinning a tire!!!! What a difference!!! drove around in 4wd, still couldn't hear the locker, I could tell by the steering it was in true 4wd--it felt different holding the steering wheel, but I could still steer pretty easy. If anyone has told you not to put a locker in the front axle of your YJ because of the vacuum disconnect, go ahead and try it. It creates no problems for me and the pulling power is awesome. by the way--$220 for the ez locker with a lifetime warranty no questions asked, $75 labor to install.