Transfer case output seal leaking again

I posted last year about replacing the transfer case output seal on my 2000 Tahoe and thanks to you guys, it was a pretty simple process. I did check it for several months after to make sure it wasn't leaking and all was fine. This weekend, I just happened to look under the truck and noticed some grease buildup on the frame and tracked it back to that seal. I could see a little drop between the rubber and the flange (rather than between the flange and the transfer case) so it looks like the seal is leaking again. Since I replaced all of the fluid last year, do I need to drain the transfer case fluid to change this again? I am not sure if it will just come pouring out when I remove the shaft, or if the fluid is elsewhere inside. Also, any tips on hammering the seal in? I remember last time, I found some blocks of wood and cut a whole the size of the seal in it and put it over the seal and hammered the block. Any better methods? Thank you.

You mean the seal for the front driveshaft output right, the two piece seal? If so I just redid mine a couple of months ago, that seal is a pain in the butt to remove with conventional methods. If not impossible, unless the tc is out of the vehicle and even then it would be hard. What I did was I used a screw and screw attachment that came in for my slide hammer. I screwed the screw with my cordless impact, pulled it out again and added the attachment, with the screw in the seal. Now that the hole was threaded by the screw. Attach the slide hammer and pull with all your might and it will pop with a bit of persuasion. That is the easiest way to pull it out in my book, without having a bad frustrated day. As far as installing it without damaging it? They sell a two piece seal installer, but you can get away with using something that fits the outside perimeter, I used one of my race installers and a good size hammer with short handle. It takes effort to make it pop in. Have a catch can ready since you will leak about a quart of fluid, so make sure you buy some acdelco auto trak before tackling it, unless you use tranny fluid like some people do. I changed mine about 2 years ago and it started leaking, I blamed the cheap seal I used before. So, I went with a good quality one this time. If it leaks again it's definitely the bearing behind that seal, and I would have to replace them all. So far it has been about 6 months and it is bone dry. Also if you go this method make sure you don't go too deep with the slide hammer screw attachment, because the bearing sits right behind it. The screw is to be screwed between the outer and inner area of the seal. So that it pinches both sides of the seal without damaging the surfaces of the tc. GL.

Rear out shaft seal... did my ‘01 3 or 4 times

Galante said:

Rear out shaft seal... did my ‘01 3 or 4 times

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Oh that one is a piece of cake, the front output is the worst seal I've seen on these.

Correct, rear output. It is very easy to get off. Do I need to drain it though?

Hello again. I am just checking back here because I am about to do this and was hoping to get an answer. Do I need to drain the transfer case fluid before pulling the shaft to replace the rear output seal? Also, what kind of grease should be used to grease the shaft when replacing it? Thank you.

Erikk quoted above that you will lose aprox one quart when you pull the seal,...replace with whatever fluid you used prior.

Shaw520 said:

Erikk quoted above that you will lose aprox one quart when you pull the seal,...replace with whatever fluid you used prior.

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I think Erikk was talking about the front seal in that paragraph above. I am referring to the rear seal.

I always replace the bushing with the seal. Your bushing is wore out letting the yoke hang down on the seal instead of nice and straight. Every new seal will leak until it's fixed. Like a bent rim....u can keep throwing new tires on but it's still gonna leak!

Wildhorse said:

I always replace the bushing with the seal. Your bushing is wore out letting the yoke hang down on the seal instead of nice and straight. Every new seal will leak until it's fixed. Like a bent rim....u can keep throwing new tires on but it's still gonna leak!

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Thank you for that advice. Is that a difficult process? I know nothing about that procedure but will do some research later and if I can't figure it out I'll come back here. Thanks again.