That's a really good description of the set-up and pre-load, terry s. That's exactly what I've been trying to figure out. So the crush sleeve is not part of the nut as I has assumed based on the price of $23.50 the dealer quoted me!

I was told here today by a mechanic that the torque needed to remove the pinion nut and replace a new one should be around 30 ft-lbs, but much higher if the crush sleeve is being installed. I suppose it could be higher than he says, but may be manageable (I hope).

Today I ordered a pinion seal made by National (equivalent to Timkin) for $9.85 ($18.50 from the dealers!) and I'll be picking that up tomorrow along with a new nut from a GM dealer ($23.50 must be dealer only, ouch) and a socket to match if needed, as well as one container of differential lubricant to top up what will be lost during the procedure. The seal I ordered is metal and rubber so I'll need some high temperature grease to apply on the rubber part of the seal, rather than the high tack gasket maker you suggested (I have that from a previous job) but that would be used if the seal had no rubber component, correct? I understand the new nut is required because of a tab on it (bending the tab on the old one back and forth would likely result in breakage I assume).

I expect to get at the job this weekend (my son drives the Jimmy to work during the week). I suppose the worst that can happen if I can't get the nut off is I'll have to put everything back and take the Jimmy and parts to the service garage down the street. I'll post again once I've attempted the job.

My wife and I are headed to Guanacaste (north west province of Costa Rica) on vacation next Saturday so I hope to have all this behind me by then at the latest.

 

OK, I got the parts and it's all starting to make more sense.

The seal has a metal outer component (bronze color) and an inner rubber component (black color). Seems like the high tack gasket sealer should be applied on the outer metal and a high temperature grease on the inner rubber with similar applications on the mating surfaces of the mount.

The nut doesn't have a tab like I was told by a local mechanic (if somebody defines those indentations as tabs, then they would be tabs, but I'm no philosopher and prefer to call things by their usual names, lol) but rather three equidistant indentations on the inner circumference which, it appears, act as pressure points on the pinion shaft as a self locking mechanism. I would agree that there is an outside chance that this self locking mechanism could be weakened by repeated removals and replacements leading to potential damage of the differential which is not a pretty thing, so a new nut is probably good insurance to try to prevent that from happening. I would probably take a chance on an older vehicle and put back the old nut, though. The size of this nut is 1-1/4 inches from flat to flat; it is a hex nut.

As the saying goes, a picture is worth a thousand words, so I've taken a photo of the parts but the image is about triple the size allowed by this site, so I'll try to reduce it in size and post it then, or upload it to a share site with a link, once I get on my other computer.

 

Here is a link to the photo:

http://s48.photobucket.com/albums/f2...onPartsJPG.jpg

The pencil points to one of the three indentations on the nut. Across from the pencil you can see a little bulge on the threads where one of the indentations is. Those bulges are what makes the nut hard to remove and put back on.

Hopefully my 1/2 inch drive 17" break over ratchet will do the trick, with a pipe extension, if necessary.

Tomorrow will be the litmus test.

 

I'm trying to get the rear U-joint apart. The bolts and brackets are off but the joint seems to be frozen tight! Don't remember this issue when I had apart last year. Do I have to hammer it loose? I've tried prying it apart with a fairly large screwdriver with no luck.

 

Oh man!

I got the U-joint off with a hammer to break the rust bond.

I then indexed the nut and shaft and tried taking it off with my 17" wrench and a pipe extension about 18" in length for a total leverage of about 24-30 inches, allowing for the overlap, while holding the flange with a pipe wrench with the handle resting on the underside of the vehicle. The wrench break over handle/pipe set up curved but the nut won't budge! So much for the 30 ft-lbs of torque the local guy suggested. (This was the same guy that wanted to work on my brakes last year to get rid of the noise I fixed by rotating the drive shaft, no wonder I don't have much faith in garages). I think 300 ft-lbs might be more like it, terry s.

Anyways I've sprayed some RustCheck anti-rust compound on the nut to see if that helps to loosen the bond the rust has on the nut. I'm inclined to think that a lot of the resistance is caused by the rust on the nut, rather than the friction between the nut and the shaft alone, although I realize that is also significant.

The other day I was checking the brake sliders on a two year old vehicle to ensure they don't seize up on me over the winter months. The sliders on the front are of the combination bolt and slider pin design. I was not able to get the lower one off. This was after taking it to the dealer over a noise the brakes were making and them supposedly replacing the brake pads under warranty as the pads had been recalled by the manufacturer. I don't know how they could have changed the pads with the bolt that frozen, but I am pretty sure they did because the pads looked quite new. I had attempted to remove that bolt the year before and could not remove it when the vehicle was one year old, and cracked a socket trying to get it loose with an extension on the ratchet handle! That first year i let it go but had to get it out this time around before it got worse. Anyways, I applied some oil to the bolt and let it go for a week, then tried again. It was still hard to turn but it came with a small strike of a mallet (this time) on the open end wrench. When I finally took out the bolt, it was full of rust half way down the threaded portion. Soaked it in rust remover for a couple of hours, cleaned it all up and lubricated it before putting back. If only the dealer had done that when he replaced the pads! The point of this story is that the rust on this nut is probably causing me much of the grief.

Stay tuned....

 

Sorry I have not been back to you. Yes 300 ft lb is closer to my guess. To the guy that said 30
The crush sleeve is like a piece of exhaust pipe with a bulge in the middle that crushes as you tighten the pinion nut.
You have it right the 3 indentations on the nut make the end slightly out of round. The other end is round and it will start on just fine then it gets harder to turn as it gets to the triagulated out of round part. Thus the self locking feature. Every time you put the nut on or take it off it looses some of the self locking ability. I don't think the mechanic has a clue if he thinks there are tabs to bend over???
Put grease on the rubber part of the seal to lubricate it. After it is inservice the diff. fluid lubes one side of it. With the metal on the out side of the seal instead of a rubber outside coating like some seals have should use gasket sealer as I described.
Next time use a tire iron to pop the u-joint out if it is stuck. Loosen the caps but don't take them off until after the u-joint is free because it mey fall out & spread the needles all over the floor. GRRRRR When you put it back put a thin coat of grease in the pockets of the flange. That should make it easier to remove if necessary in the future.
Diff. fluid will come out when you take the flange off so have a pan ready. You may have trouble with the fluid coming out and contaminating the gasket sealer. Be sure to inspect the sealing surface on the flange.
Keep us posted.

 

Thanks again terry s. Your insights are very welcome.

I know that diff fluid will come out, but don't know how much. I've got a quart ready to top up afterwards. Hopefully that will be enough. If the diff fluid that comes out contaminates the gasket sealer, it shouldn't matter too much if I use some gasket sealer on both metal surfaces, the seal and the mount.

I've read that I may need to get a three point puller to yank the flange once the nut comes off, but am hoping that won't be necessary, even though I can borrow that from the parts supplier.

I've tried that darn nut every day since Saturday and can't get it to give any. I think the RustCheck stuff hasn't had a chance to work its magic on the rust yet. I may have to leave it a few more days. Today I sprayed on a bit more. Either this works, or I have to use my hydraulic jack on the break over bar like you've done, or put everything back and take it to the garage (as a last resort).

I will use a bit of grease on the pockets of the U-joint flange from now on. I don't expect that grease will last all that long, everything seems to wash away under the vehicle with all the salt, snow, water, etc., but it will delay the onset of more rust. I get my vehicles dripless oil sprayed every two years and still rust seems to develop in all kinds of spots! Rust never sleeps, as Neil Young says in his song!

 

I have not needed a puller to get the flange off. A few taps with a hammer is the most I have needed. If you do nees a puller it will need to be a 2 jaw puller.

After you get the seal in you can clean well with brake clean and silicone between the outer edge of the seal and the housing. It might not be necesary but easy to do and might prevent it from seeping. Also don't forget to make sure the vent on top of the axle housing is open. If it gets plugged up pressure inside the housing will build up when the housing and fluid heat up such as when driving on the highway particularly in the summer. The pressure can push fluid past the seals.

 

Thanks again, terry s.

Finally the nut came off. Once the oily goo ate through the rust, the wrench and pipe extension was all it took to start turning it. It took about 30 inches of leverage and all the strength I could throw at it with my right arm. I'd guess that's well into the 200+ ft-lbs of torque just to get the old nut off the shaft most, if not all, due to friction as nearly the same amount of torque was required to keep it turning the first several turns. The old nut looks quite round, it's lost a lot of that bumpiness in the threads, so it is a good idea to replace it as it would no longer have the same ability to self lock as a new one does.

I've tried taking the flange off by hammering, but it seems it's too well frozen in place and I don't want to damage it with harder hammer blows. I'm off to borrow a puller from my local parts supplier; I hope they have one available when I get there, I'll take whatever they have.

The vent above the housing I think goes up into a tube just inside the rear fender if I recall correctly from last year. How can one tell if there is anything in it without taking the tube off and blowing through it?

 

Good choice to get a puller. I did not mean to beat it off. Many times a few taps is all it takes.

The tube on the vent is to keep water from getting into the vent if you go through deep water. So keep it up high when done. See if you can remove the hose. I am not sure on a 2005 but clean around the vent and see if it just unscrews. They usually are just a simple check valve that allow pressure to excape but not let stuff get in. Others are kind of like a loose bottle cap sitting over an opening in the tube (vent). It acts like an umbrella to keep stuff out but not as good as the check valve type. I have actually removed one that was plugged and heard it hiss as the pressure was releived.

I don't remember if I mentioned it but diff. fluid can sometimes seep past the splines. So clean the splines on the pinion and in the yoke real well as well as the big washer. put some gasket sealer or silicone around the splines so the washer will press it in & around the splines and make a seal.