Nobody said this was easy, although the guys in the net videos certainly make it look that way!

I was able to remove the flange with a 4" puller kit. First I attempted to use two jaws because it was easier to hook it on, but quickly learned that I would need all three because of the amount of force required to remove the flange. Fortunately the kit I borrowed allows for the two configurations. I had to use the pullers almost until the flange fell off - that's how snug the flange was on the pinion shaft! Anyways that part is done. I've lost about half of the diff fluid because the vehicle is sloped a bit - with the tires about 3-4 inches off the garage floor.

Here's a picture of my flange with the inner side facing up:
http://s48.photobucket.com/albums/f2...current/Jimmy/

Next I tried pushing the new seal in after applying a thin coat of gasket sealer all around the lip of the seal where it mates up with the housing when it's pushed all the way in and some grease on the rubber surface in the middle. The problem this time was I couldn't get it to go all the way in. I cut a hole in a piece of 2X4 for the pinion shaft to go through so I could tap the seal in evenly, but still the seal wouldn't go in. After tapping on it for a while I pulled it off again and the metal outer portion was distorted and it appears that it has a rubber coating on the surface that slides in which is no longer smooth. I don't know if the part was defective or what. But the parts supplier told me that he's never a had a defective National seal come back in 25 years! Since no one ever has produced 100% non defective parts, it seems to me that he finally has a defective National seal on his hands, LOL. He's ordering me a new one for tomorrow, but was wondering if I should be getting an OEM seal from the dealer. I once had a front bearing replaced on a car that just would not work (made clicking noise after installation) and finally had to order one from the dealer which worked perfectly, but don't know if I am facing the same crap here - aftermarket part that doesn't cut it!

The vent has a wire spring clip on the tube to hold it on the spigot and I was able to squeeze that spring clip and move it back, but the rubber tube doesn't want to pull off. Does it just take brute force or is there an easier way to pull it off? I see someone in a net video forcing one off on a Ford with a flat tipped screwdriver but I can't even get the tip of the screwdriver on the end, and the spigot must be an inch long! I really want to get this sucker out because there is a good chance it has crap in it that caused the seal to leak in the first place and would likely do the same to the new seal if left the way it is.

 

I have had seals that were very difficult to get in without distorting them and others were easy to get in. Only a slight difference in diameter can make the difference between being hard or easy to get in.

In the past I have bought different brands of lower ball joints that press into the lower control arm on older gm cars. Without a press I could not get them in. I tried ball joints from the dealer and they pressed right in every time. The aftermarket ball joints were slightly larger than the gm ones.

The secret to getting the seal in without distorting it is to get it started evenly and tap it in using a slow even process going around the seal. Only use enough force to tap it a small amount at a time and keep moving around the seal slowly tapping it into place.

I'm not sure on getting the hose off without seeing it. If the vent is metal you can try squeezing the hose with pliers where it fits over the vent and see if you can rotate the hose. If so it may then losen enough to pull off. If that won't work or if the vent is plastic can you just cut the hose off and put a new one on? Does the vent appear to screw to the housing or is it pressed in. If it screws in see if you can just unscrew it.

 

I think the seal might be just a tad too large, but I will try one more. If I can't get that in I will then try one from the dealer. The differential on this vehicle is a limited slip differential, I don't know if this kind comes with a slightly different seal and the aftermarket guys don't know about that! I tried tapping mine in gently going around with the wood over top and when it wasn't going in I tapped gradually harder until it deformed. When I pulled it off the coating on the sliding surface seemed to be coming apart! I'll bet this is the first one these guys have sold for an '05 Jimmy!

The vent appears to be just a metal tube (or spigot) coming out of the top of the differential housing and the rubber tube going straight down over it so that the end edge of the tube buts right down on the round differential housing. It does not appear that there is any removable fitting connecting to the differential housing, but I can't be sure until I pull the tube off. The rubber tube is quite long and attached to the inner body of the vehicle at a couple of places with clips (seems hard to get at those!).

 

Is there a check valve at the other end of the hose? There should be one somewhere to let the pressure out but not let water or dirt in.

 

The other end is pretty high up and I don't even remember ever seeing it, but I'll have to look for it. You're thinking that perhaps the bottom isn't meant to come off, are you?

I just took the two seals and compared them side by side by eye, realizing that just a hair difference could mean an easy fit or a hard fit. They seem to be identical in size, but what I noticed is that the rubber that wraps over the metal where the two materials meet is quite deformed, don't know if it was partly deformed before trying to install it and then it got worse trying to force in; I suspect that's probably what happened. Or, I might have been a little sloppy with the gasket sealer and accidentally got a little on the side rubber, but I don't think so, as i was careful to get it only on the end metal lip. What I also noticed is that the old seal is considerably heavier than the National seal, so it would withstand a little more force when being pushed in. The National unit is rather flimsy, which partly explains why it deformed so easily! The rubber on the old one is still in good shape even after prying it off with a screwdriver, which obviously deformed the metal lip.

I'm going to see if the parts supplier has a seal installation tool and look at the rubber on it very carefully to try to ensure that I can install the National replacement seal without incident, otherwise I'll have to buy an OEM seal at twice the cost!

I've noticed a lot of white gunk on the spline that is really hard to remove. Does that need to be cleaned off thoroughly? How, without mucking up the gear oil that's left in the diff?

 

I think there should be a check valve somewhere. If it is on the end of the hose take it off and make sure you can blow through it as if pressure were excaping from the diff. Then make sure you can blow through the hose into the diff. If so you don't need to remove the hose from the diff.

The difference of 1 or 2 thousandths of an inch can make a big difference as to how hard it is to get the seal in. You need a dial caliper to measure this. You can't tell by looking.

I believe the white stuff on the splines is some type of sealer. If you leave it on it may help seal. Use the old nut to get the yoke seated and take the nut off. Then clean the area ahere the splines come out of the yoke and clean the washer. A tooth brush & brake cleaner should work. Then use silicone or gasket sealer to seal under the washer where the splines come out of the yoke and put the new nut on.

 

Thanks terry s, I got the job almost completed. The seal went in finally. I talked to technical support at National and was told that the seal I have is indeed the one for the vehicle, and that the seal is 2.657 inches and the housing 2.653 inches, so that the seal has 4 thousandths of an inch for compression. It was still quite tight and tough to get it in but it's in. The drive shaft is also back on. The diff took a whole liter (about a quart) of oil to the fill hole and then I put the spent oil in the bottle and there was only 700 mls in the bottle meaning I had already lost 300 mls (10 oz) to leaks! That oil I had put in last year was golden when it went in but it was quite black when it came out! It doesn't take very long for it to look awful. The vent ends with a loose hose end up behind a U-channel that appears to be part of the vehicle's frame. It's nearly impossible to reach, but there is nothing on the end, it just has a 180 degree turn so it points down. I cut the hose just above the spigot because there was a fair bit of slack to re-insert it shortened, and then pulled off the bit over the spigot with a pair of screwdrivers. The spigot seems to be clear and sticks up about 1.5 inches above the diff housing with a lip on the end angled downward to hold the hose once the clamp is put on. At its base the spigot seems to have a small round base above the diff housing about 1/8 of an inch thick, so it doesn't appear that it is meant to screw off - I can insert a wire in it and push it down nearly 3 inches before it hits something, I assume the gears. I can't get my head in there to blow through the tube but might be able to run a piece of soft copper wire through it to see if it reaches the end. At least I got this far today with temperatures around 10 degrees C (about 50 F) before the big cool down expected to hit here tomorrow - just a bit above freezing with possible flurries. Hey, this isn't KC. I'm hoping to wrap this up tomorrow so I can start packing for Costa Rica to get away from this weather.

 

Completed the job this morning. I connected a compressor to the bottom of the hose and I could feel air coming out of the top end - no blockage there. So I inserted the bottom end of the hose onto the spigot and clamped it; obviously this leak was not caused by a blocked vent. Might have been the dried up white gunk that GM had used on the spline - appeared to be some gasket sealer that got all dried up, started falling apart and may have caused my leak. Got to get some sleep before heading out to the airport in about six hours. Thanks again terry s. Your help was awesome as usual. Cheers

 

U R welcome. Glad you got it done.