Chevy & GMC Vans

Has anyone had to change the oil pan on a AWD 2004 Astro? It seems that the front diff must be lowered. Tips will be appreciated.

Yep, good luck and enjoy. Be sure to check your motor mounts too, if bad they can allow the oil pan to contact the front diff and damage the pan.

I decided to replace the motor mounts prior to the leaking oil pan once I saw how bad they were and gouging the oil pan.

Yes, you need to lower the front differential some for pan clearance on removal. You may need to rotate the engine clear the crankshaft too. Wiley gave me the heads up on rotating the crank which definitely helped.

My front timing cover/crank seal was also leaking so may be worth checking/replacing those as well. You'd probably achieve a better seal if you did replace the timing cover with oil pan since you can run a bead of sealant to mate/seal them together properly. I used a Fel-Pro oil pan gasket and OE GM timing cover/seal kit from GM Parts East after reading too many bad reviews about Dorman timing cover kit.

I ended up replacing a ton of other stuff at the same since I was there for preventive maintenance and other leaks like p/s pump, etc.

I guess I never posted a write-up here but here is the link to my thread on Expo: http://www.expeditionportal.com/forum/t ... ost1696823

A couple other things I can think of off the top of my head:

If replacing timing cover again, I'd partially install the harmonic balancer before tightening the timing cover which should possibly help better align crank seal on crank. Don't forget a dab of sealant on the crank keyway to prevent oil getting past too. Since my harmonic balancer had a slight groove worn in it from the crank seal and I couldn't clean it up enough I installed a repair sleeve on the balancer.

I've done funner jobs! It wasn't to bad, but I too had to lower the front diff. slightly. The crux for me was the little 10mm? bolt that holds the oil line clamp to the pan; I slotted that hole for re-installation and it made life easier.

I've done it with the front diff completely removed, made the job pretty easy.

photo_van wrote:I've done funner jobs! It wasn't to bad, but I too had to lower the front diff. slightly. The crux for me was the little 10mm? bolt that holds the oil line clamp to the pan; I slotted that hole for re-installation and it made life easier.

That bolt is a pain. When I replace oil cooler lines I left it off and zip-tied rubber tubing around the lines along the oil pan to prevent any rubbing issues. I was going to replace it when I did the oil pan but the rubber tubing was working well enough.

Thank you very much for your help. My oil pan was broken and welded by the previous owner, who is my father in law and I knew the damage before I bought the van. I has only 50 k miles and shows no oil leak in any other place. I will do the job once I receive the new pan and gasket from GM US.
Will post how it goes. Thanks again, from Santiago, Chile.

Hey Strover. How are those poly motor mounts? Do you notice much increase in vibrations? I'm starting to have a little pulley rub on the tierod issue now and again so thinking replacement.

photo_van wrote:Hey Strover. How are those poly motor mounts? Do you notice much increase in vibrations? I'm starting to have a little pulley rub on the tierod issue now and again so thinking replacement.

Hi photo_van, I like the poly mounts. They do transmit/provide more feel/feedback but in a positive way not an annoying vibration way. I also replaced the trans mount with poly and that was a noticeable difference as well.

When I start the engine, nothing moves around, shakes or vibrates and smooth at idle and when revving engine, no rocking, etc. Just more solid feeling and less craptastic overall.

Ok, that's good enough for me. Pricey, but worth not having to do it again. Unlike the water pump that I'm replacing today that I just did 30k ago Figured while I got the front apart, good time to get at the mounts, I'll order some, thank you.

And now back to oil pans.....

BTW, re. oil pans- I got mine thru ebay after I put a hole in it; $35 delivered!

When anyone wants to remove and replace an oil pan in this AWD 2004 Astro, besides all instructions you may find in the literature, also remove the bolt at the lower side of the bracket that holds the right side of the diff assembly. It is easy and lowering the bracket makes the job possible. See picture.