Stuck Rounded Transmission Fill Plug

[ben550]

So I bought fluid to do a drain and fill on the transmission. I got under the truck (V8 06) and due to past learning experience... I began to try to remove the fill plug before draining the pan. The 24mm 6 point socket had some play and would not budge the bolt. I sprayed pb blaster on the bolt and let it sit for a while then tried again. The bolt began to round. I then went out and bought a 15/16th 6 point socket which fits a bit better (less play) and tried again. The bolt rounded some more and did not budge.

How should I go about trying to get this bolt out? I have a replacement bolt ready to go. Should I spray pb blaster and get attempt it while it is hot? I don't want to do any damage by hammering and there is not a lot of room to work with. Its a pain to access.

I'd appreciate any suggestions.

 

[fdbyrne]

Since you have a replacement fill plug on hand and are planning on replacing the old one anyway, you have a few options.

First, I'd try tapping it with a hammer a few times to shock-loosen the seized threads. If that didn't work, I'd try heating up the plug with a torch. If that didn't work, I'd go to Harbor Freight, buy a big set of vise grips, lock those babies onto the rounded off bolt and then crank away on the vise grips with a section of pipe attached to the handle.

The vise grip thing has worked for me many times.

 

[BOSMECH]

Hit it with a imppact hammer gently and it will come out, just one short burst.

 

[chompster4runner]

Impact work wonders. If you can get a plumbing wrench in there. It should be able to grip it nicely. Never failed on me.

 

[KBToys]

I've had a 50/50 success rate using these.
9 Pc 3/8 in. Drive Metric Bolt Extractor Socket Set