T18 Leaking!

[MaxKlinger]

hey guys,

I changed the gear oil on my T18 about 2 weeks ago. I noticed that the oil that came out was at least a quart less than was supposed to have been in there; now I've found out why. It's leaking like crazy!



I know this picture is somewhat dark, but you can see the shiny area on the bottom of the transmission case where it is slick with brand new golden brown gear oil.

It's not leaking at all by the output shaft. I can't quite tell if it's the side access door or the input shaft that's leaking, I think it's unlikely to be the input shaft from where I'm finding the oil:



I keep finding oil where the red oval mark is. What is this plate on the side of the transmission for? Is there a gasket I can replace here? It doesn't look like there's any gasket material there right now, maybe that's the source of the problem?

Thanks for the help, guys!

[spartman]

IIRC that plate is the blockoff plate for an optional PTO.

There should be a gasket there.

You can just use silicon and make your own.

[AlleyCat]

If you have trans rebuilder or truck parts dealer near you check with them.Tell them you need a gasket for a 6 bolt PTO. Tell them it's for a cover plate.Cover plate gaskets are thicker than shim gaskets that are used to set gear lash when installing a PTO.

PTO= power take off.

[lightning_msd]

i had the same problem when i first bought my 67 with a T-18, i changed all fluids in the truck and that was the only thing that leaked alot... all i did was use some silicone form-a-gasket, and its still holding up, i also put some copper anti-seize on the fill and drain plug, those dont leak anymore either, i didnt use a lot, just a quik wipe with a brush...

[MaxKlinger]

Tell them you need a gasket for a 6 bolt PTO. Tell them it's for a cover plate.

Are PTO interfaces standardized? In that case, would cover plate gaskets for 6 bolt mount all going to be the same?

Thanks!

[FLATBEDFORD]

Are all 6 bolt ptos interchangeable? Or are they specific to a transmission? Will one from an NP435 work on a T18?

[averagef250]

PTO's are specific. Some interchange, most do not.

Gaskets leak, RTV does not. OE's have eliminated most cork/paper gaskets in cars over the past couple decades. Don't use a gasket.

[fordman]

silicone or make a gasket with generic paper gasket materail or go buy a ready made gasket. if it is that bad of leak that the plate might be warped you can use a ceral box as a gasket it thicker but its aslo a weaker type of gasket making material.

[AlleyCat]

MaxKlinger and FLATBEDFORD, the 6 bolt mounting flange is an SAE standard used by all O.E.M.'s and component manufacturers.There is also an 8 bolt version. PTO's themselves are made for specific transmissions and while they will bolt up they don't ( with rare exceptions) interchange.

[MaxKlinger]

Alleycat, thanks for clarifying. So SAE standardized the housing interface, but not the drive interface. Interesting.


Ok, dumb question here. Is RTV a silicone based sealant? Can I buy this in any auto parts store? Does Permatex make an RTV product?

Thanks.

[DuckRyder]

RTV is Silicone

RTV = Room Temperature Vulcanizing

[averagef250]

Any old silicone will work. RTV is made for this, but you can use tub and tile caulking if that's what you have.

[MaxKlinger]

Thanks for the help, guys. Did this yesterday and after allowing the RTV to cure I filled the trans and took her for a ride, not a drop after about an hour of running. Another problem solved.