3 speed transmission with odd hole in case

[Foot Stomper]

Hey guys, I bought this transmission (with a receipt that it was rebuilt at a machine shop) and once it was filled, we noticed oil on the floor. Tracked it back to coming out of this tiny hole. The hole is below the fill plug level.

Is it supposed to be there?
Can/should/how I plug it?
Will plugging it cause the case to build pressure and blow out elsewhere?

I appreciate any help on this.

[4x4k30]

well from where I see the spot that leaks it doesn't look rite it should not be there . it looks like the transmission has a crack in it. and it should not leak at all. you might want to clean off that spot and see if there is a crack . the transmission may have broke something inside the case. its made of cast iron and not easy to repair

[68gmsee]

What transmission is it? Can you get some numbers off it?

To get a better view of the hole see if you can spray some cleaner around it to get a better view and see if there's a crack in the transmission.

From what I can see in my computer it doesn't look like a round hole that was intentionally made there. There's two options you have -maybe three. One is to take it to a shop to have them look at it. You can also have a professional welder weld it or braze it. Third option, if it's just a small hole with no cracks, is to drill it and tap it and plug it with a bolt or other type of plug.

[Foot Stomper]

Thanks for your help guys.
I agree with you that it shouldn't be there regardless.
Not sure about the hole shape as I'm not with it currently but will consider tapping a hole and/or welding.
I like the bolt idea if tapping it works easily.
Welding an oily hole may be more challenging.

[68gmsee]

Yeah, welding or brazing may be a challenge that's why it should be done by someone experienced in doing it. Either way, you can clean around it real good to see if it's just the hole or if there are cracks around it. It's possible it may have been a casting defect that went unnoticed.

I once had a 2 inch hole in a block welded that was caused by a piston rod cap coming loose. Even though the welder did a good job, it still oozed a small amount of oil around it due to heat stress fractures. I still drove the truck for several years before selling it.

[YoungPup1977]

You got it from a machine shop with a receipt......take it back to them and see what they will do for you....unless they told you about it before you bought it........Good Luck !!!

[Foot Stomper]

Originally Posted by YoungPup1977

You got it from a machine shop with a receipt......take it back to them and see what they will do for you....unless they told you about it before you bought it........Good Luck !!!

No, I didn't say that I got it from a machine shop with a receipt. What I said was "I bought the transmission (with a receipt from a machine shop)..." this doesn't mean I bought the transmission from the machine shop... I would have said that if that was the case and I would have taken it back without posting here about what to do about it ... thanks for your advice anyway...

[Bigdav160]

I'd drill a hole and put a small pipe tap in it.

[YoungPup1977]

"Hey guys, I bought this transmission (with a receipt that it was rebuilt at a machine shop)" Sorry, I really must of misunderstood your english...... getter done.. Tap and go.... put thicker gear oil in it, the weather you have will never thin it out and it wont leak.... Must be something about someone having an odd hole and they don't know what to do with it.....JB WELDING fixed it...

[Foot Stomper]

Problem solved.
Checked around and it turns out the hole is supposed to be there to accommodate a pin that holds a shaft inside. Turns out the pin was pushed in a touch too far so a dab of JB Weld on a cleaned surface is all that was needed.