How do you know if you need new seals?

[67D100Pickup]

First, if you've read some of my other posts you know I'm not a mechanic. Just trying to keep the truck running in good form...

I'm seeing oil dripping from the clutch cover.

How can I tell if my transmission seals are good?

If I tilt it back and oil comes out does that mean it needs a rear seal?

Same for the front?

Jeff

[martincom]

Which engine? It could be the transmission input seal or the rear main seal. However, if it s a V8, the usual culprit is valve cover gaskets. They become hard, from the exhaust manifold heat, and will not seal any more. The oil usually flows along the edge and down the bell housing.

I've been utilizing Moroso valve cover gaskets from Summit Racing. They're pricey, but they last quite a bit longer, are re-usable, and they don't leak.

[67D100Pickup]

Which engine? It could be the transmission input seal or the rear main seal. However, if it s a V8, the usual culprit is valve cover gaskets. They become hard, from the exhaust manifold heat, and will not seal any more. The oil usually flows along the edge and down the bell housing.

I've been utilizing Moroso valve cover gaskets from Summit Racing. They're pricey, but they last quite a bit longer, are re-usable, and they don't leak.

It's a 318, just rebuilt. I've been watching the valve covers closely. Yes, they were leaking initially but I've tightened them several times and I think they're stable now but I'll check out the Moroso gaskets. Thanks for that tip.

Meanwhile, I have the transmission out of the truck now. Is there some test I can do to see if the seal is good or not?

Jeff

[PwrWgnDrvr]

Get underneath with a flashlight and look up inside to see where the oil is coming down from. Also, smell the oil. If its tranny oil the stink is undeniable.

[martincom]

Yes, they were leaking initially but I've tightened them several times

You've probably over tightened them. Over tightening causes the valve cover metal, around the bolt holes, to be drawn down. Then, the only contact pressure is just around the bolt hole. When you remove the valve covers, place them upside down so the corner of a vise jaw is supporting the top of the valve cover, around the bolt hole. Use a hammer or a combination of ball peen hammers to pound the gasket face back down. I typically tighten valve cover bolts to 55 inch-pounds or thereabouts.

[67D100Pickup]

Yes, they were leaking initially but I've tightened them several times

You've probably over tightened them. Over tightening causes the valve cover metal, around the bolt holes, to be drawn down. Then, the only contact pressure is just around the bolt hole. When you remove the valve covers, place them upside down so the corner of a vise jaw is supporting the top of the valve cover, around the bolt hole. Use a hammer or a combination of ball peen hammers to pound the gasket face back down. I typically tighten valve cover bolts to 55 inch-pounds or thereabouts.

I've used a torque wrench each time to 20 inch pounds. No leaking now.