Pulling a 99 GMC Sierra 4l60e and was following a how to from here on the forum. My torque converter to flywheel bolts are not 15mm like the how to, they are Allen heads. Any body know what size these are so I can go buy the right size?

Since all forums enjoy pics here's the truck in question.



And here's what I'm dealing with now







Reason for all of this is I lost 2/4/reverse so I'm pulling it to rebuild/replace.

 

Iirc they are either 8 or 10 mm but most times the oe converter bolts need to be air hammered out and replaced... They have an updated design, with 15mm hex head as well as the allen head!!!

 

Yup, 8mm or 5/16" should work if you have one laying around.

 

All I had laying around was 1 of those fold out Allen key sets but none were near that big. I'll be buying a set today for the impact.

 

Do not impact it, it will strip out try to get it with a small extension and a breaker bar.....if not but anair hammer....

 

Alright thanks for the info. Are you guys just wedging something in the flywheel to keep it from spinning? And on the air hammer are you just chiseling them off?

 

With air hammer (if it gets to that) try to hit it as square as possible it will break loose then you can spin it out by hand, as far as trying to break them loose the extension or head or ratchet/breaker bar against block and when it feels like something breaks it shoukd be loose... If you have someone to hold the crank bolt while youre breaking the bolt loose that will help!!!

 

Personally I used a 1 ft pry bar on the teeth of the flywheel. Also remember to never use your oil pan for leverage.

 

Why i said against the block tgui! the bolt will break loose before the side of the block or pan give way....

 

Next time i have one that is overtight i need to take a picture of what i am talking about.....but thise first design bolts are a pain in the *** that never shiudlve been used... **** poor design!!!