Oil Pan removal

[Foley]

I'm new to V6 GMC's and have to replace the oil pan on my 305e. Doesn't look like it will hardly come out of there without pulling the engine. Do I have to remove the exhaust pipe yoke to get to those pan bolts? And is there enough room for it to slide out after that? Any magic tricks that I should know? Bob in Northern CA

[jimjaz]

Bob,

This might help answer your questions about oil pan clearance-
Mine's a 4-wheel drive, so there is really nothing in the way, like the crossmember.

[Foley]

Nice pixs Jim. I wish this was a 4x4. On the 2wd the main front, bigol cross member sits right there across the middle of the oil pan about 2.5 inches below it. Now that all the pan bolts are out, it will only drop down a couple inches and not enough for it to clear at the back where the big ring gear sits. I was hoping somebody might have done this before and could provide me with some tips on the pan removal. Bob in northern CA

[jimjaz]

Bob,

I've not had the "pleasure" of having to remove a pan off of a 2wd version; only my 4x4. Unfortunately, even removing the flywheel from the crank rear (which would involve pulling the transmission and such), the oil pickup tube would most likely still be in the way of allowing the pan to clear.
The only way I'm aware of in your situation would be to hoist the engine from its' perches enough to slide it forward on the trans input shaft and then lift it enough to get the pan to clear the obstacles. That's a bunch of work for a pan pull.
Why do you need to get the pan off? If you have leaks at the front or rear main seals, then that could indicate another problem.

For what it's worth; when I drove this 4x4 Suburban beast back to Phx from Southern Cal years ago, I thought that the ride home was pretty rough, but attributed it to the old mud-n-snow worn out tires, like they were square and not really in round, if you will. I stopped for gas about midway (of course), and checked my oil level- I had used at least a quart of oil and found a pretty good size puddle of oil coming down out around the rear main seal and it freaked me out. Then found during restoration that I had a pretty good shimmy with the engine idling or otherwise- an unbalance situation. I pulled the tranny out, and no change, then pulled the clutch and pressure plate assy, most of the shimmy went away. I took the clutch assy along with the flywheel to King Balancing local here in Phx. When it was ready, he reported the flywheel to be something like 7 grams (not a bunch) out of balance, and the (previous owner replaced) clutch and pressure plate assy to be like 87 grams out of balance. HUGE! No wonder the poor engine was struggling and leaking oil. Good thing these big V6's are tough, or I could have blown the whole thing up driving from Cal to AZ. After I installed these balanced components back, she runs like a real happy camper- no more vibration, and magically the rear main oil leak stopped, except for the occasional drop or two. Moral- balancing rotating parts is very important and saves any engine from an early demise. I was lucky.

[Foley]

Well, here we are some days later and the oil pan is off. What's inside on the bottom of the pan is another story, but in order to get one off of a 2WD, remove all six bolts/nuts of the exhaust yoke and take it completely out, remove the oil filter, then loosen all four engine/trans mounts. Take all of the pan bolts out and it will drop down about 1/2 inch and you can slide it back some. That'll give you enough room to use the pan edge on the front of the block for a lifting surface. I placed a bottle jack under the 4 speed tranny case, and one under the very front edge of the engine block. I had to jack that assy up just a little more than one inch before there was enough clearance for the pan to tilt down and slide out the rear, clearing the ring gear. Amen!

[FetchMeAPepsi]

What a deal Foley. Thanks for posting the how-to though. I woulda never thought it would be so hard to get an oil pan out of these old machines. Wow!