You can replace the seal without taking apart the transmission. Just be certain that the contact area for the seal on the shaft is smooth as glass. Even then it's sketchy on whether it will seal back up or not. For some reason mine was leaking, put a new seal in, drove it in straight as a ruler with a piece of pipe and lubrication, but I still have an oily bell housing.

 

Like mentioned the seal can be replaced from the outside. Just have to remove the collar the throwout bearing rides on. If the input bearing is bad it requires trans to come apart.

 

Okay cool. Maybe jumped to conclusions on this one a little.

They replaced the rear seal while the trans was out for the clutch job…it had been seeping for awhile. Got it all cleaned up back there to keep an eye on it. Been fine for a couple weeks. Found a tiny little streamer of oil back there too this morning along with the dripping on the front and that got me to thinking they might not have unscrewed and really cleaned out that breather on the top of the trans. Yesterday, it was kind of warmish for November and I was pulling a decent sized 5th wheel into a little breeze heading south towards Indianapolis, so the transmission got warm…150-160*F which is the first time that had really happened since it all went back together. Coincidence a new seal plugs up the rear and suddenly the front one springs a leak the first time the gearbox gets hot? I have my suspicions that breather is still plugged up, so we’ll see now.

Glad to hear it’s serviceable without taking the transmission apart at least. It’s over there now getting a new pinion seal and nut and rear axle serviced. I’m supposed to take off 1300 miles for San Antonio Sunday and didn’t need this but that transmission might have to come back out again to fix that.