4th Gear Issues can be quite irritating. Recently, I had the honor of tracking down a problem on my 240 concerning 4th gear and its inability to shift into said gear. A rebuilt trans was in order as the orginal transmission had issues due to a failed rear seal and bushing. The previous transmission would not shift into 4th gear. However, the rebuild also refused to shift. I found later that the transmission relay (located under the glove box) was acting up. As you might guess it would seem that perhaps the orginal transmission was ok after all. Imagine my relief when it was opened up and indeed a valve was stuck. Quite a coincedence. One suggestion to anyone having 4th gear problems check the relay and wire leading to the relay, all the way down to the plug on the transmission. It is very possible that this is where the problem is.