69HurstOlds

My 455 started leaking oil from the trans. dust cover and I suspected it to be the rear main seal. But after I took the cover off and got looking at it, the leak seems to be coming from in between the the flexplate and torque converter. Is there any way it could be leaking from where the pilot bearing is, or are the cranks in these engines solid? This has me puzzled, any help would really be appreciated, Thanks.

67Olds442X2

The end of the crank is solid where a pilot bearing would be on a manual transmission car.
Usually when the rear main seal leaks, oil goes everywhere because of the spinning flex plate.

Oldsmaniac

Only places are rear seal, rear cam plug, or oil galley plugs that are behind the trans. Crank is solid so cannot leat at pilot bearing which only stick cars use.

69HurstOlds

The back of the motor is dry, and the rear main is not showing any signs of leaking. The ring of oil that is slinging out on the trans bellhousing is after the flex plate, between it and t. converter. T. converter has and oily residue on it toward inside and it was dry when I put it in. Also the crank has oil on it where it bolts to the flex plate. All of these reasons are why I'm not convinced it is rear main or the other places that where mentioned. Thanks for the info so far.

1968Cutlassfallbrook

What color is the fluid that you're talking about? Also you said you installed the converter in dry? Do you know if the torque converter was properly seated? Normally they recommend putting at least a quart of trans fluid into the torque converter when installing a rebuilt trans and torque converter.

69HurstOlds

Golden brown. By dry I meant on the outside, not inside. Guess I should have said that.

67Olds442X2

Is the motor dry on top around the distributor area, back of the block? Something could be running down the transmission flange.
Oil pan rubber seal?
If it's engine oil, all points where it could be leaking have been mentioned.
If the torque converter shield is collecting engine oil, and the motor's dry on top, rear main seal is most likely the problem. I've had the same thing.


Best bet is to clean everything on then run the motor and check for leaks with the converter shield off. This may sound crazy but if you have ramps, put the car on them and run the motor. Take and look underneath while it's running. You could use a mirror and flashlight so you wouldn't have to actually crawl under. Or run it a bit, shut down, then crawl underneath. Know where the exhaust pipes are at all times. Good luck.

69HurstOlds

67 when your rear main leaked, was where the crank exits the block wet with oil? Mine isn't wet there and shows no signs of oil coming from that area. Also the oil ring around bellhousing doesn't line up with that area either, it starts after flex plate and is like 1.5" wide. I had it idleing for about 5 mins. or so (enough to warm it up) and it wasn't leaking then. Any thoughts?

67Olds442X2

Mine had a little where the crank exits, I had installed my rear seal bass akwards. Oil was everywhere and hard to pin point until I pulled the motor.

Yours is odd indeed, aft of flex plate then torque converter is throwing whatever around. Oil can't get to the TC without going through the flex plate. Was the dust cover all oily on the inside? Wish I could be of more help but I'm at a loss.

ah64pilot

Is it a freshly rebuilt transmission? It sounds like a front seal on the tranny to me...

69HurstOlds

Yes the dust cover had quite a lot of oil in it.
Yeah, front seal is new and isn't leaking. Thanks for your imput.

ah64pilot

And you are sure the back of the engine (distributor area) is dry? I just ran on the dyno and had a manifold leak at the corners where the manifold meets the head and oil ran down under the head, down onto the bellhousing area. It got onto the flexplate somehow...

Just another idea

69HurstOlds

I'll double check but from what I could tell it was dry.

ah64pilot

Let us know...it could be leaking from the back of the manifold and coming down the back of the bell housing.

69HurstOlds

Checked that area again and it's dry. Any other ideas? I'm stumped.

ah64pilot

At a loss brother...any chance it could be coming from the front of the motor and getting caught on the flexplate cover?

69HurstOlds

Not from the looks of it. Everything in front of the flex plate appears to be sealed. I was thinking maybe its trans fluid coming from the TC, but it really looks like motor oil. Both fluid levels are down so I can't tell from that.