How to drain fluid from a th350 pan no drain plug

[76k5blazerr]

I'm gonna be changing the fluid and filter on my th350 this week, this is the first time I've done it on a tranny without a drain plug in the pan, what's the best way to drain the fluid without making a mess? Also I know the TC will still be full after I drain the pan so what does the stock pan hold? About 4 quarts or so?

 

[K85 Octane]

Loosen the bolts slowly, making sure either the back or front is more loose so it can tilt towards your pan. It will be a disaster anyway. Keep a couple bolts in the front while you tilt the rear more.

Once it's off, get a plug made up for it, maybe even a temp sensor that can also be used as a drain.

 

[76k5blazerr]

And to clean the pan once it's off can I use brake clean?

 

[diesel4me]

There is no "easy" way to drain the pan without getting a Dextron shampoo--they sell large plastic funnel shaped drain pans as large as a plastic garbage can lid that helps catch most of the flood when you pry the pan down and let it hang by a bolt or two,but often the crossmember or other obstacle wont allow you to drop it low enough to get all the fluid out and it ends up all over you by the time you get the pan completely off..

I've tried siphoning or pumping the fluid out thru the dipstick or the hole the stick goes into,but it still leaves enough fluid in the pan to be a mess when you lower it...some tranny shops just use an air chisel to poke a hole in the pan and install a drain plug in the hole..even that can get messy though..

I bet GM saved a whole dime on each vehicle by omitting a drain plug on automatics...I'd have paid extra to have one...my older pre-1972 TH350's all came with drain plugs..only owned one GM with a torque converter drain plug too,on a Th400...rarer than a hen's tooth..

 

[Zeus33rd]

It is very very worth the investment to get a pan with a drain plug on it, if money allows. Just the money saved in pan gaskets, the time saved changing fluids and the convenience- less chance for mess, spills & having to buy kitty litter etc. to soak up spilled atf, is worth it. Cast aluminum one even better.

 

[76k5blazerr]

I have another pan from my old transmission that has a drain plug. Probably will put it on in place of the current pan when I do the fluid change.

 

[blazinzuk]

Drill a hole in it

Probably a good idea to get the drain plug kit also and drop the pan after most of the fluid is out and 8nstal drain plug kit.

Gotta be quick to get your drill out though

 

[Blue85]

I bet GM saved a whole dime on each vehicle by omitting a drain plug on automatics...

I don't think it was just cost savings - they may have made that up in dealer service anyway. At some point they decided that owners shouldn't be messing with the transmission. Everyone has heard stories of a dummy draining the trans, adding 5 quarts to the engine and starting it up, but it's hard to know how much of a problem this really was.

I would look at pictures of plugs on TH350s to know what a safe location is, put a collar on a drill bit and put a hole in it first thing. I had a drain plug kit from B&M once, but it would turn sometimes instead of the plug and could leak:

I like the factory style drain plugs best (they have the rubber seal built into the underside of the wide head) and they're just a few bucks at the local parts store.

I put one in my 4L60E using a castle nut upside down so the fluid could drain lower. You just tighten it in place with a standard bolt to keep it square while welding. But those have an area on the bottom stamped in, to use this style on the side of the pan, you might have to go a little higher than the universal plug kits. But the important thing is just that you can drain below the pan gasket.

You can also install a temp sender in the pan and use it as your drain plug, but then you do have worry about messing up the capillary tube or breaking the wire when you do.

 

[EXJAY]

I saved an old air handler overflow pan for messy jobs just like this. Has a T handle valve already on the pan for easy draining.

 

[Deuling]

It is very very worth the investment to get a pan with a drain plug on it, if money allows. Just the money saved in pan gaskets, the time saved changing fluids and the convenience- less chance for mess, spills & having to buy kitty litter etc. to soak up spilled atf, is worth it. Cast aluminum one even better.

I agree completely. I added a drain plug toy rear dif and will be adding one to the front dif and trans pan next time they are out.