As far as a special tool, no. The easiest way that I have founs to replace the rear output shaft seal is just get a pair of channel locks, and lock onto the lower part of the seal and pry against the upper part of the housing, the seal should pop right out. Of course you will have to pull out your tailshaft, but this is no big deal. Would be a good time to inspect the shaft for wear anyway. Probably be a good time for a fluid change as well.

 

When I put in my new clutch last week and refilled the oil in the T-case, there was a big puddle of fluid on the floor in the morning. It was coming from around the front output shaft. IT WAS NOT A SEAL PROBLEM. The big nut that holds the output flange was loose, I tightened it and no more drips, CHECK THE NUT.

 

Man, you guys must be deprived in the auto parts stores... I picked up a rear output seal from advance auto for like $12. They had every seal listed for a 231, 241 and 241HD. This was for our gasser plow truck, but it still has a 241HD t case and same driveline of our trucks aside from the tranny.

 

The trannies are virtually identical too. Different T/C, VB, and maybe the pump.

 

I'm sure you have the wrong seal for the diesel. If yours doesnt have the large black rubber dust cover that protrudes out the back about 1" then it isnt right. You can find the seal without that boot all day long and the funny thing is the reference numbers dont show anything but the flat seal.