Extension Housing Rear Oil Seal Replacement

[BillyJoBob]

My 97 Astro needs the seal replaced which means I have to remove and replace the front U-joint.

Seal looks easy once I get the drive shaft dropped in front. I'm looking for suggestions of how to get the U-joint out and back in working on my back on the ground. I did a search here and didn't find anything. Everything on youtube seems to be on the bench

Any suggestions on greaseless vs non-greaseless U-joints appreciated also

Thanks in advance

BJB

[AstroWill]

Why are you removing the front u-joint?

[BillyJoBob]

Cuz the Service Manual sez too. If I don't, please tell me how to get to the seal?

[Astrofarian]

Unbolt the u-joint straps from the differential, remove the driveshaft from the differential, slide the slip-yoke out of the transmission extension housing. The seal is now right in your face.
Which "service manual" do you have, out of curiosity?
-M!ke-

[BillyJoBob]

Thank you

The official GM 1998 Chevy Astro 3 volume set

[AstroWill]

I would be interested in seeing that from the manual, could you scan and post it?

[BillyJoBob]

ment]

[Astrofarian]

Propellor shaft/Driveshaft needs to be removed, yup. But you DON'T need to "remove" the u-joints, per se. They'll both get "removed" with the driveshaft. Once the driveshaft is out of your way, you're done with IT and the U-joints until it's time to re-install it. Helpful hint: wrap the differential end of the driveshaft (the u-joint) a few times around with electrical tape to prevent the cups from falling off and scattering needle-bearings all over your garage floor.
-M!ke-

[AstroWill]

I was just wondering if you were looking at the wrong section or something. Yes the drive/propeller shaft has to be removed, but you definitely don't have to remove the u-joints unless there is something else wrong and they need to be replaced.

98_prop_shaft.pdf

(47.73 KiB) Downloaded 29 times

[BillyJoBob]

See? And that's why this forum is so valuable, not all of know what we need to do.

Thank you both

[Astrofarian]

If you're working "on the ground", as you indicated, make sure to get some 3/4" plywood (not O.S.B.) to put under your jackstands. I gather from your last post that you don't have a lot of experience doing automotive work? No judgements, just curious.
--M!ke-

[BillyJoBob]

Thanks Mike but it's 'generic' ground, on a concrete garage floor.

[AstroWill]

See? And that's why this forum is so valuable, not all of know what we need to do.

We all learn from each other. Let us know how it goes.

[Mmusicman]

The manual may tell you to pull the tail-shaft housing because some seals do not have a lip to easily knock it out, and you'll have to work around the tail shaft. But I have never pulled the housing to replace a seal. It's ok to destroy the seal while removing it.. just use care not to damage the housing. Sometimes I pound a flat-blade screw-driver right though the metal portion of the seal and leverage or bend them out.

As far as replacing the u-joint goes.. you most certainly can replace it in the ground as well. It may not be the preferable way.. but I've replaced many this way. A big hammer and a couple appropriately sized sockets should do the trick. Be aware some u-joints have inner-clips which must be removed first. No amount of hammering will get them out if you miss removing the clips (ask me how I know.. lol) Some u-joints use "nylon pins" which you simply ignore and hammer though. Some people drill them out.. some (I think) even melt them out.

Either type of u-joints are fine. "Greaseless" (as you called it.. the correct term would be non-greaseable) are typically used in high-performance or 4x4 applications where stressful high-torque is a factor. They are not cross-drilled for grease fitting in exchange for strength. Standard u-joints however, typically have grease fittings, so you can lube them annually. Both have grease in them, it's just one allows you to add more later without pulling it. Both types are fine in our application. The factory joint I believe comes with no grease fitting.. and this joint when properly installed can last decades.

As far a brands, (if possible) stick with DANA or SPICER... they are the undisputed best.

[BillyJoBob]

I bought the seal yesterday and am wondering if I should be lubing it with anything in particular before I install it?

TIA

[paulo57509]

I bought the seal yesterday and am wondering if I should be lubing it with anything in particular before I install it?

TIA

You can lube the lip if you want to - use ATF.

[BillyJoBob]

Thanx

BTW, 2" ABS pipe fits the inside metal ring perfectly. I'll go thru my fittings and see what I can fashion so that I can hold it straight when I tap on it. I'll report back when I see how it works.

Don't have any of that? You can buy 2' sections at Home Depot for a few bucks and put it on the front seat next to you