Getting ready for a complete front suspension and steering replace on my ZR2. Thought since I would have the torsion bars off would be a good time to replace all of those bushings that I can. Might as well drop the tranny for rebuild and transfer case for inspection and reseal. While I am at it I might as well drop the front diff and do the 4WD engagement system. So there I will be with just the motor sitting there just begging for a lower end reseal. I have already done the Intake, valve covers, distributor gasket and sending unit reseal. Have a small leak where the oil pan meets the timing cover and a bit of oil coming from the bell housing. So wouldn't this be a good time to correct those leaks. Question is, do I have to remove the timing cover to replace oil pan gasket and rear main....and any other things I might have missed.

 

The way I see it, if you're to be doing that much work, you might as well do everything you can while the spots are still relatively easy to get to, instead of later on with the other parts reinstalled.

 

Short answer is yes. After the front cover is off, then the front diff has to be dropped a bit in order to get the oil pan to clear and drop off.
To get the transmission off you get to drill a hole above the accelerator pedal to access a bell housing bolt.
From what I have read a special tool is required to install the rear main seal.
New timing cover since they are plastic and since you are moving the crankshaft sensor, the Relearn must be done after all put together.

And to get timing cover off, water pump comes off, coolant drained - good time to flush system out.

Where do you stop....when you run out of funds.

Take lots of pictures as I need to replace the rear main seal and timing cover on my '02 4dr, 4wd. Really tired of the oil puddle.

 

Photos of installing rear main seal with the Kent-Moore special tool and differences in timing cover and timing chain tensioner kit is in post 28 of https://blazerforum.com/forum/2nd-ge...e-87514/page3/

 

You don't need to do all that. I have done it a number of times as it sits.
But to make it less of a pain, unbolt the tranny x member and tranny mount, drop the tail end of the tranny down till the tcase sits on the torsion bar x member. slide the tail end over a couple inches. It gives plenty of access to the hard to reach bolts, and no hole in the floor for moisture to get in thru later.

To answer your question: you might as well pull the engine and do new oil pan gaskets, timing chain cover, water pump gaskets and rear main seal.

I dont reccomend changing the timing chain cover without also changing the oil pan gasket, because they interface with eachother, and you're just asking for a leak if you do just one. Also, use copious amounts of rtv on both sides of the gasket where it interfaces with the timing cover... ask me why lol

It also wouldn't hurt to change the timing chain and gears while in there. I got a timing chain/gear kit from a 350 for cheaper than the one for the 4.3, it's way beefier and a direct fit.

 

I was going to remove the tranny, and t-case cross members along with the front diff anyway since the tranny will be going in for service and t-bars will be off for LCA rebuild. That should allow for tilting down for that hard to get bolt. All of this will be done on a lift in my welding shop so I thought the oil pan and rear main would be simple from that vantage point just don't know if I have to pull the timing cover for oil pan gasket.

 

no, you don't have to pull the cover for the oil pan(you do have to pull the oil pan for the cover though.) But for like 25 bucks, I would replace the timing cover while you're there too.

 

I agree.......just wish I would have been this ambitious about the other repairs while I was doing the lower intake gasket, would have made things easier while I had the front of the engine apart. Oh well nothing like doing a job twice. Thanks for the input everyone.