I've been searching around the board for the like 15 minutes for some info, but not having great luck, but learning alot.

I just put in a new (used from salvage) auto trans in my 85 camaro. The Camaro had an oil leak before, but real minor, just a drop or two.

Well, since it sat for about a year, that oil leak has gotten much worse. I'm suspecting rear main seal. While reading the board, I've found that the distributor and intake are typical places to get leaks too, so I'll check them too.

Question is, if it is the rear main, what is involved.

It sounds like with a 2 piece, you can do it by just removing the oil pan (leave tranny in place). Do you need a cherry picker to pick up the engine, or will it come right on out once unbolted? Then it sounds like you pull the bottom piece of the seal out, and then push/pull the top piece around till it can come out the bottom too? Is that right? Installation the reverse? This sounds like it should be fairly easy.

If it's a 1 piece I'll need to pull the tranny off. Now do I have to pull it all the way off, or just unbolt the torque converter and engine bolts, and leave everything else connected? Unbolting the tranny wasn't to bad actually, 4 bolts in the crossmemeber, 3 in the converter, then drop it a few inches, and get the 6 in the engine. The pain was the tranny cooler lines, mounts, cables, etc.

Lastly, anyone know what I should have in there, 1 piece or 2 piece?

 

Its a PITA job. It would depends on how high you jacked the car up. with a lift you could do it much easier. On your back in the dirt, it best to just yank the tranny. If the pan is coming off either way I would, I would put in new rod and main bearings. Like $100 n worth the extra effort.

If it is some fancy race engine then you would want to take spec's, measure lash and all kind of stuff. Just new stock spec bearings will be fine. Unless you know they are different.

 

If it's a one-piece seal, you have to remove everything from the rear of the crankshaft; which is why you have to remove the trans. You'd have to remove the TC and the flywheel.

Are you sure it's not just your distributor o-ring leaking? Feel around at the base of the distributor and see if your fingers get covered in oil. That's just a 2 cent o-ring, 1 inch inside diameter, 1/8th inch thick.

Oh, duh, I forgot one bit- 85 was the last year for the two-piece seal. So you don't have to worry about a one-piece.

 

Replacing the seal is a piece of cake. Pull the tranny, leave it resting on whatever you dropped it with (tranny jack, floor jack). Yank the seal out, put the new one in, and rub a little Black silicone around the edge of it. Put the tranny back in and you're set, whole job should take a novice about 3 hours, more if you're drunk .

 

Anyone ever overlap the seals??? Remember doing a pinto once with a two piece. Guy said not to use any silicone but to over lap the seal. So each end of the seal stick up or out so it cover the seam on both sides.

 

Yeah, I'm gonna take a good look at the leak this weekend and try to determine exactly where it's coming from. It's definitly the back of the engine somewhere, and I'm just thinking RMS is the worst case thing.


Is this a good thing? It sounds like the 2 piece is easier to fix, atleast. Is the 1 piece a better seal?

My Chilton manual has the following steps (for 2 piece), this will hopefully help the next person who wonders what is involved:

1. Disconnect battery
2. Remove distributor cap - (Kinda wondering why? Maybe so it doesn't hit firewall/cowl?
2b. Remove fan shroud (another V8 only thing)
3. Raise vehicle
4. Drain oil
5. Remove air injection pipe at cat - (I don't think I have this. My cat (gutted) has a little pipe coming out of it that is capped, maybe this was a v8 thing?)
6. Disconnect exhaust pipe at the manifold - I hope this isn't neccessary. One of my drivers side bolts broke off in the manifold already
7. Remove starter
8. Remove front engine mount through bolts
9. Raise engine
10. Remove oil pan bolts
11. Remove oil pan
12. Remove oil pump
13. Remove main bearing cap
14. Remove seal from bearing cap
15. Remove upper seal by using a small punch to drive it far enough around to be pulled out with pliers
16. Install seal using RMS special tool. Coat lips and bead of seal with light engine oil but keeping oil from ends of seal.

This doesn't sound too bad. Any suggestions for raising the engine? Do I need to get an engine crane for that? If i recall, Harbor freight has em, and I don't think they were too expensive. Any alternative?

This atleast makes me feel better about just reinstalling the transmission. I would have felt pretty stupid to have just installed that tranny, only to have to pull it again to fix the rear main seal.

FYI, the Chilton manual kicks the crap out of the Haynes manuals I see everywhere. My neighbor gave me a Chilton manual (he used to have a 3rd gen), and it is WAY better. Haynes manual has no explanation at all on how to do RMS from what I can tell with engine in the car. I'm never buying a Haynes manual again.

 

You are better off dropping the tranny, removing the oil pan is a pain, you end up having to buy a new gasket usually, new oil (good idea anyway but...). Removing the tranny is a simple procedure, don't be affraid to do it. It will probably take you LESS time than doing the 2 piece seal method (which is usually harder more likely to have problems.). Even if you have a 2 piece seal, id recommend changing to the 1 piece (i think there's a service bullitin). Do it right and enjoy a PERFECTLY sealed main-seal.

 

If you end up converting to a 1 piece, I'm pretty sure there's some kind of positioning pin that you would have to remove somewhere around the rear main.

Is it actually possible to change to a one piece? I always thought differences in crankshaft design make it impossible...

 

I have seen adapters to convert old small blocks to use a one piece rear main seal (and allow the use of a late crank), but not for a 2.8. It may exist, but I have never run across it.

Your leak may very well be the rear main, but another possiblity is the rear cam seal. There is a three bolt plate above the rear main that covers the camshaft, and is exposed to some high pressure oil. If its leaking, it will leak WORSE than a rear main. Good insurance to go ahead and replace it; its a dealer item, but cheap. The parts stores don't list it, at least none of the ones I checked.

 

I've only seen adaptors for a newer sbc to use an earlier style crank, but there sure as heck ain't one for a 2.8.

 

85 was the first yr for the 1peice rear main.

 

You're right on both counts...I realized I stated that backwards as soon as I logged off. The ones for SBCs are to use an early crank in a late block, not vice versa.