So my transmission is officially gone so I am pulling it off and replacing with used or rebuilt one...

can it be done without removing the y-pipe? These bolts seem extremely stuck. They are soaked daily for a week with pb blaster and I am thinking of getting a mapp torch but i am still afraid to break a stud.

if a I break the nut/stud off the y-pipe to manifold bolt, do people normally drill these out on the vehicle or start taking off the manifold then?

 

You are going to have a very hard time removing the trans without removing the y-pipe. There just isn't enough room without removing it.

Heat will help greatly, but the kind of heat you need doesn't come from even a MAP gas plumbing torch. You'll need oxy-acetalene. The trick is getting the heat into the nut really fast so as to limit the amount of heat transmitted into the stud.

If you snap one off, you could try removing it with the manifold in the truck, but that can be an exercise in frustration.

 

Do you know if the bolts in question are pressed or screwed in? If they are pressed, can they be hammered out?

will the manifold to head bolts probably also be seized?

 

They are threaded in to the exhaust manifold.

 

i asked the same question. i used a craftsmans bolt/nut remover for stripped nuts and a cheapy 12v impact and replaced the nuts on the mani - ypipe. on the back end i broke them off as they were that bad and just had the studs drilled out and put in bolts. i had trouble drilling out the bolts on another one of my cars so i just used a griner and went at iut from the side. with 3 like on the blazer in that senario it won't come apart

 

Using an oxy-acetylene torch, I still managed to break 1 bolt on the y-pipe to cat connection.

Are these pressed in as well or threaded? Any hope for an air hammer or does one usually drill these out? (the broken one is on bottom and will have about 1/4" of threaded bolt protruding once y-pipe is removed).

 

You got all the hard nuts off already. I would slice the bottom at a 90 degree angle with a whiz wheel. Grind right through the stud. It will collapse with vise grips and turn out. Pop s new 3/8 bolt and a few fender washers in its place and you should be golden

 

So split the button pointed to by the arrow as deep as I can get with a die grinder? Then use vice grips on stud?

 

Just started this project today. The left side nuts came off ok. Now the right side is giving me hell. Been soaking with wd40. The nut on inner broke loose and nut on right towards wheel well is rounding. How do you get to the upper nut with cat in way. It's sucks I'm down to 2 lousy nuts. The left side had me confident this was going to work out well, guess not.

 

Just an update. http://www.irwin.com/tools/screw-bol...-deep-well-set
Found these at Auto Zone. These are a miracle. Removed the 2 toughest nuts to remove with ease and no slipping. They have great grip. So guess I was right with them coming off.
So no heat required in my case.