Thread: Transmission Drain Plug Stuck

Hey fellas. I have a problem with a transmission I was looking to use on one of my cars. The drain plug won't spin loose. Its stuck. I tried using a 1/2" impact extension and it won't move. I have the correct square plug socket and tried using a long extension bar and it won't budge.

My next plan is to separate the case and soak the interior of the plug with some PB blaster and then try to torque it loose again.

Other options that I'm thinking about is somehow using heat, but I'm a bit hesitant with that because the transmission case is made of aluminum.

My last resort is to drill out the plug but I'm not sure how I would go about repairing the threads once I drill out the plug.

Has anybody ever managed to solve this issue with their own transmissions?

I know some people just leave the plug in there and drain from some other hole. I just don't really like the idea of having to loosen one of my switches every time I need to drain my transmission or worse yet popping out an axle every time I need to drain.

Problem with removing the axle is that only removes about a quart of fluid before its below the level. The reverse switch is probably the next best bet.

However i would do all you can with as big of a breaker bar as you can. Ive had it happen on one and it took a huge steel pole on top of a breaker bar to break the thing loose. It had a damaged thread that whoever put it in before put it in just far enough for that last damaged thread to screw in and stick. The drain plug is pretty hard material. I dont think removing the case and pb blasting it is gonna do you any better. Maybe just heat the plug up a bit before using the breaker bar. Just dont heat it up too much to the point where you start burning the silicon sealing the case or to the point where you crack the case. Just take a propane torch to it for a couple seconds each try. It should eventually break loose.

Torch the bolt for about 10 seconds then try to loosin it up.

A few firm taps after you heat it, may help.

torch the case not the bolt. If you torch the bolt, the bolt will expand instead of the hole and you'll never get it out. Aluminum doesnt elongate very much when heated and by the time you heat it long enough, I would imagine your going to melt the silicone between the case and bellhousing. If it were me, I would just use the lowest switch on the back, its not like theres really anything additional that needs to be removed to take the switch out other than unplugging it. Just put some teflon tape on the threads when you put it back in and you'll have no leaks and be good to go.

Just be very careful not to let your wrench slip and smack the case when removing the switch because you can put a hole in the case that way; ask me how I know.

I am not sure ,but I think this was the fill plug size,but heres what I did...I was amazed how well it actually worked.
You should be able to do the same on the drain.
I got this at ACE hardware,but its a common tool and brand.

You will need a SHARP 3/8" drill bit to drill slowly until you ALMOST go through the plug.
DO NOT drill all the way through lor you are done and will have shavings in the tranny.
Whack the extractor in the hole with a hammer.It will bite real good if you do it right.
I just ised a 12 point socket and ratchet,and it came out like butter.

I had tried many ways to get it out before I finally just went and bought the extractor.The square ones work better than the spiral style...I tried them both and returned the other,lol.

Good luck.
I always check the fill plug before I pull the drain after that so I know I can fill it if I drain it.

Had the same problem but with the fill plug. Had to torch it to get it loose.

I have had this happen a few times. Pb blaster and a torch will help get it loose. A very large breaker bar will also help . I have also had one the would not come out and had to drill it. I still have it sitting on the floor in the garage. If it will not come out then you have to change the diff cover. Another trick to use is to wrap the head on the allen key in masking tape. this will take up the extra room in the plug and keep you from side loading. I use this same method on stubborn head bolts. If you do it this way you will need to tap the allen key in place.

I've had the same prob several times, both times I've used a chisel and tapped the edge of the plug inwards all the way around that I could then jammed the 1/2" breakover bar back in there ... heat would be good too, if you have the case off, heat the piss out of it, you should be fine as long as all the plastick guides are out of the case and such.

I had to remove the drain on my old Z31 with a breaker bar, and a 6' pipe. I find that firmly tapping, not wailing, on stuck bolts helps to loosen the threads. I've had to get under the car and push with my legs to break some bolts.