I have a 98 2 door tahoe with the push button 4wd. The rear output seal on the transfer case (drive shaft to rear axle) has been leaking for a while now. Recently it seems to be getting worse. I had the seal changed three times over the last couple of years. The first time the transmission shop used the cheapo ten dollar seal. Most recently, about a year ago I had a shop put a seal on it from Oreilly's. I think it was about $30 to $35 and is much more robust than the first one. It's still leaking. I also think the shop just put Dex 3 ATF fluid in the case as the leaking fluid is red. The truck has 235K miles on it. Other than the leak, the transfer case works perfectly. My question is would the GM seal work better than what I have and could using the correct fluid in the case (the blue stuff, I think) make a difference. Is there another internal seal or bearing going bad that could be causing the leak. Any info would be greatly appreciated. Thanks!