Replacing front axle shaft seal

[webbch]

I have a '90 Silverado 3/4 ton 4wd. I've been noticing a gear oil leak at the point where the passenger side front axle shaft goes into the front differential. I've removed the passenger side drive axle (CV halfshaft), but I still need to remove the axle shaft (the part that goes into the front differential) so I can remove the seal and replace it. My concern is if this axle shaft is supporting a bunch of gears that all drop down when I slide it out (couldn't tell from the service manual if this would be the case)

Anybody know how to remove the passenger side axle shaft? Hopefully it can be done with the front diff (carrier?) still in the truck, but I'll do whatever it takes.

BTW, here's a link to the diagram of the front diff (you have to scroll down a little to see it).
http://www.trademotion.com/partlocat...13&catalogid=1

The part I'm needing to replace is #4

Thanks.

Chad

[79403ta]

my 97 should be about the same as yours... you will need to unscrew the actuator (#8 in your link) take the passenger side axle tube off mine was 4 bolts yours should be similar be very careful when doing this there is a spring (#14 on the link) it dont have alot of pressure but its a spring it will shoot pretty good....dont lose this mine shot out and it took 20 minutes to find it...the reason why you have to pull the tube is there is a spacer in between the gears that keeps them from rubbing on each other it is basically a washer (its between #10 and #11 they dont label it but its there) it rests on a nipple that is on the end of the axle shaft (#1)...basically you have one gear on the shaft then the nipple with the spacer along with a sleeve (this sleeve has teeth on the inside when you put it into four wheel drive the actuator pushes (#13) which applies pressure to the spring and then to the fork which slides the sleeve over and splines the two gears together and then you have four wheel drive) then the other gear (#16 which is actually an inner shaft but you will only see the end with the gear on it) which is in the housing...i tried to just pull the shaft out of mine like you are wanting to do to replace the seal and that little spacer fell and the axle wouldn't go back in...i didnt have a diagram but i pulled mine apart and put mine back together no problem all you have to do is watch how it comes apart and use a gasket on the axle tube or some good RTV silicone when you bolt it up... when you put it back together you will need to put everything in the tube then bolt it back up being careful not to drop that spacer i mentioned...it sounds complicated but its not...its easy it took me about 2 hours and i was taking my time....a little hint when you are trying to get the axle out of the axle tube tap on the flange (where the cv boot was bolted) and it will slide out

[webbch]

Yeah, the front diff on your '97 does sound pretty similar from your description - I noticed the shim washer to which you refer.

For just the axle shaft seal that I'm looking to replace, I could've done it with the front differential still in the vehicle. However, I decided to pull it anyway. I have to replace one of the oil lines, and removing it gives really easy access for that oil line.

It was surprisingly easy to remove. A total of 4 mounting bolts and slide back the propeller shaft and out it came. A little bit heavy, but with a floor jack to help me out it wasn't too bad. I separated the axle shaft tube from the rest of the front differential, and will pull the seal out tonight.

BTW, I didn't unscrew the actuator, just unplugged the connector. I don't think that step is really necessary. Unfortunately, I *did* forget to disconnect the vent hose, and tested the yield strength of the plastic nipple that the hose plugged into while lowering the front differential. Hopefully I'll be able to find a replacement.

Chad

[webbch]

Update:

It (front differential) was surprisingly easy to remove

....and surprisingly difficult to put back in (working by myself), LOL. My first attempts tried to "orient" the front diff, balanced on my floor jack, hoping that I could just lift it up into place. Nope, it required a very special trajectory to get it into place ("over the river and through the woods...."). Used some 12/3 romex wiring to tie it off during various phases, what a PITA.

Interestingly enough, the replacement axle shaft seal was not a tight fit in the housing. The one that came out wasn't particularly tight either. A very light tap of the hand was all that was required to get the new one in. I tried 3 different ones, and they all had the same fit. I looked at the housing for evidence of the previous one "spinning" in it's bore, but didn't see anything unusual. Granted, the axle has some kind of dust cover (part #3 in above link) that covers up this seal when installed, but it still left an odd feeling in the back of my mind. We'll see if it leaks again. I still have to put in some 80W-90 gear oil, and finish putting the front driveline back together before I'll be able to test it. Oh yeah, and my water pump started leaking in the middle of this, so I'll replace that next as well

FWIW - As far as breaking the vent hose nipple (stupid mistake), I couldn't find one at the dealer. It's a large plastic "cup" that threads into the diff case, that has a plastic nipple at the center (not illustrated in the above link from what I could see). Fortunately, I was able to repair it by drilling out the plastic "cup" to the OD of the nipple to a sliding, almost press fit, and then using some plastic cement to "glue" it together. Amazingly, you can hardly tell it was ever broken, and just as strong.

[wolfden6]

What does the shift fork connect to??

Is it the connector sleeve??

My front axle ill not engage and the actuator is working and I removed the actuator and tried to use a piece of dowel to push the shift shaft and engage the axle and it would not budge and was stuck so I am lost about what is going on in there.

Any suggestions??

[MT-2500]

Originally Posted by wolfden6

What does the shift fork connect to??

Is it the connector sleeve??

My front axle ill not engage and the actuator is working and I removed the actuator and tried to use a piece of dowel to push the shift shaft and engage the axle and it would not budge and was stuck so I am lost about what is going on in there.

Any suggestions??

Best to Start a New Thread with your problem.

If you can not push in on the plunger you will need to remove the actuator tube and look inside.
I have had them lose the snapring that holds the axel shaft and chew up the thrust washers and jam the shifting gear.
MT

[79403ta]

have you replaced the axle seal ??

[wolfden6]

Not yet...I am going to tear into it soon...just worried how involved this will be