best way to drain torque converter still in truck

[dbmx66]

trans cooler in the rad sprung a leak, coolant has been going into trans.
i drained the trans fluid (strawberry milkshake) out, but there still some in converter.

id rather not deal with unbolting the engine and trans to pull it off and drain it.

some one told me i can drill and tap a 1/8npt on the converter, drain it, then plug it up. any opinions?

and other ways to do it?

thank you

[lazypineapple]

Flush. Machine
or a hillbilly flush,
Drain and refill several times.
Posted via Mobile Device

[Palf70Step]

Install a drain plug in your pan. Drain and add tranny fluid everytime you change the oil. Within a few oil changes it will have ciruclated thru. Keep doing it and it'll keep your system with fresh fluid.

[C-10 simplex]

Originally Posted by lazypineapple

Flush. Machine
or a hillbilly flush,
Drain and refill several times.
Posted via Mobile Device

Yes, Isn't there a transflush or some other machine that can take all the old fluid out and put in new?

2) I've seen the drain plug procedure in the TQ, but it has to be done right the first time; If you need more info i can look it up over the weekend.

[C-10 simplex]

P.S. i heard there is a way to drain all the fluid out completely and it has something to do with opening up the transmission line circuit----in other words instead of having one of the lines go to the radiator---i'm assuming the line TO the radiator, this line instead goes out into the "atmosphere"/into a bucket etc. And then fresh fluid is introduced into the system.

i can look it up over the weekend or tonight etc. When do you need this done?

[lazypineapple]

Transmission flush systems.

Those oil change place have them.
Kwik car.
Tune and lub
Posted via Mobile Device

[dbmx66]

I need to get this done asap

My daily driver took a crap and this truck is all i have, because i cant daily drive my pro street 78

The truck is not inspected,so taking it somewhere to get it done is out of the question

Im really thinking about attempting the drain plug, i work in a cnc machine shop, i have the right tap size and tap drill size, all i need to know is where to put it.
Posted via Mobile Device

[lazypineapple]

What if you take the cooler lines
Ones a suction and ones a discharge.
Put the suction in a bucket of clean fluid
And let the discharge run in another bucket.
Start motor an let idle till fluid runs clean.
You may have to raise fluid bucket above tranny so gravity will help.
Posted via Mobile Device

[dbmx66]

i could try it, but the trans itself has no fluid, so id have to fill it before i start it, would i be pumping out the fresh flud i just put in?

[lazypineapple]

Yup
just buy 2 cases of ATF

Seems like drilling the converter you risk hitting the stator with the drill bit.
An messing up the balancing of the converter.
Posted via Mobile Device

[dbmx66]

thats what ive been hearing, but if a put in an aluminum 1/8 npt plug that will be almost the same weight

and im very low on $ so i dont know about paying $40- $50 in trans fluid just to drain it, just i can put anoth $40-$50 of fluid back in

[raceman6135]

[Gumby]

just buy a new TC or get a used one from a reliabel source.
[not out of a blown trans]

gonna cost money either way.

[1LowToy]

Honestly I've never had any luck with getting that much moisture out of a tranny. Good luck and keep us posted

[Stew_Magoo]

Originally Posted by lazypineapple

What if you take the cooler lines
Ones a suction and ones a discharge.
Put the suction in a bucket of clean fluid
And let the discharge run in another bucket.
Start motor an let idle till fluid runs clean.
You may have to raise fluid bucket above tranny so gravity will help.
Posted via Mobile Device

There is no suction. The trans pump pushes fluid through the cooler and pushes it back into the pan.


Here is what I would do, and have done.

Get four or five GALLONS of correct ATF, have it ready in gallon jugs. Disconnect the cooler lines and connect them to some hoses going to an empty five gallon bucket. Have a funnel in the fill tube of the trans. Start the truck, and pour clean fluid in as your old fluid empties from the cooler lines to the bucket. Do this until you are happy with the color of the fluid coming out.

[rs72z]

What trans do you have is the first thing we need to know. If it is a th 350 or 400 you can drill and tap just like the picture above shows. I have done it plenty back a few years ago. No problem with balance either.

[C-10 simplex]

According to Ron Session's TH-350 handbook (an excellent book in my opinion) you'll need:

Center punch at the spot raceman pointed out above
drill a 1/8" hole, the bit must be sharp
After letting it drain
lightly deburr with a 1/4" drill

The thing is you have to rivet it shut---i don't think you can plug it?

This method seems risky, i can give you more detail out of the book if you really want to try it.


What he suggests and prefers is to flush it:
Disconnect the trans cooler OUTLET line (i originally got it wrong), should be the top one and attach a 3/8" rubber hose to the radiator fitting.

Run the engine and when the fluid changes to looking fresh you've done it.

i think he's saying cooler outlet because there is also a few quarts of old fluid in the trans cooler as well. Need to get that out as well.

i don't know if there is enough "meat" in the converter to where you could actually tap it so that's why he said rivet. Some after market converters have a drain plug, but that's custom anyway where they took the whole converter apart etc. And or made their own body with thicker walls? i don't know.

Is trans fluid really that expensive? i haven't bought some in a while.


Oh P.S. i just read your, Rs's Post. i wasn't disagreeing with you---if it works---the plug then great. i don't have any experience with it, i was just reading out of the book and trying to formulate why he would say rivet instead of plug. But if it works for you great!

[rs72z]

All you have to do is tap it 1/8 pipe and install a plug.

[crazeetxn]

Neighbor of mine growing up (good 20 yrs ago) did like raceman shows. He had an '86 with a TH350 I believe. He said that's the first thing he had the tranny shop do when he rebuilt it. Just drilled, tapped, and plugged. When he drained the pan, he removed the plug to get everything out.

Saw him a while back at the store when I was home...he was still driving the truck!

[Gumby]

Originally Posted by rs72z

All you have to do is tap it 1/8 pipe and install a plug.

The weight of the plug will toss it out of balance, the rivet method is more sound as the aluminum rivet will be just enough to replace the steel lost in drilling.

[kelsfine69]

FYI....It cant be just any old Rivit. It has to be a Sealed Rivit.

[rs72z]

Originally Posted by Gumby

The weight of the plug will toss it out of balance, the rivet method is more sound as the aluminum rivet will be just enough to replace the steel lost in drilling.

Over the years of building 350's and 400's i never had any problem with a converter being out of balance from drilling and tapping it for a plug. I know of one 350 that i built more than 20 years ago that is still in use to today, and it was drilled and tapped.
I'm not trying to start a argument, but it works.

[78 Chevyrado]

If you used a rivet to close up the new hole, how would you drain the TC at a later date? When you remove a rivet, you drill it or grind it off and this would leave a piece of it floating around in the converter.

Seems like if you used a rivet, that means you would be drilling a new hole to only drain the TC ONCE.

I wonder, If theres a worry of imbalance using a threaded plug, couldnt you put in two of them, 180 degrees apart to keep it in balance? Or would that weaken the TC case too much?

This would be a great mod, I got to liking it after we did the trans on my dads '98 F150, as it has a threaded drain plug in the TC. made it so much easier. Got a lot of extra fluid out of it.

[Keith Seymore]

Originally Posted by 78 Chevyrado

I wonder, If theres a worry of imbalance using a threaded plug, couldnt you put in two of them, 180 degrees apart to keep it in balance?

- Yes -

But I don't think it's necessary.

As noted above, people have been putting a single drain hole in converters for many many years, without issue.

K