I'm pulling the transmission to do a clutch job on my 2001 Civic EX. I'm following the service manual for the procedure. 13-6 step 13 says to remove the transmission mount bracket, which I did, and then the transmission mount bolt (circled in blue). This bolt will not move. My Hercules 59398 High-Torque impact wrench has succeeded only in making the bolt head shiny. I had sprayed Rustoleum rusty metal primer on visibly corroded parts in my engine bay a couple years ago, including at the exposed end of this bolt. I applied a 50/50 acetone/ATF mixture to both bolt ends, which also takes this paint right off so I'm not really worried about it being "painted shut" like a window. Only thing I can think of is removing the three bracket fasteners first gives this part no leverage to unbolt from. I visibly saw this while first attempting with a 1/2" breaker bar, the mount just started to rotate with the breaker bar. So I re-installed the two nuts and snugged them down. The center bolt stripped some serious threads upon removal so I'm not really able to re-install, and am planning on installing a Time-Sert for this hole on the bench. There's another bracket right in front of the bolt head (you can see it has a clean brass circle where it receives the transmission ground strap) which interferes ever so slightly with side/angular force while using a 17mm long socket on my impact, I've also tried a short wobble extension with a regular impact socket to avoid bracket interference completely. And no beans at all. What can I do in this situation to remove this bolt?

 

Well I got it. I don't really know how. I walked away for an hour then came back, still no luck with my 1200 lb-ft impact. But a 1/2" breaker bar broke it loose. Even then, my impact wouldn't turn it so I had to unscrew the bolt with my breaker bar one turn at a time until it came out. Once I re-removed the nuts from the bracket studs, this bolt slid right out. Maybe having the nuts removed was a good idea after all? I think in retrospect maybe leave the nuts on, break it loose, remove the nuts, pull out bolt. The only thing resembling an explanation I have is the Acetone/ATF mix had an hour to work. I pulled all kinds of threads from the back so will be Time-serting this bracket as well.

 

If I'm planning to start working on my car on Saturday. I try to spray all the bolts down with penetrating oil Friday evening.

Also, this is a handy item to have around when bolts are not wanting to free up.
Mayhew Tools 37315 3/8" Shake N Break Bolt Breaker