[Jdeaton01]

OK... Well I was getting my transmission back in this afternoon.. I've had a lot of problems with this truck and getting it road ready.. and today, the very first bolt I turned on broke..

it's one of the transmission mount bracket bolts.. the ones that bolt to the transmission. It's on the side that goes all the way thru..

Can anyone tell me what grade this bolt is? How long it's supposed to be? And it being broke in aluminum, should I drill it out and tap it, or helicoil??

I'm going to try extractor first but I doubt I can get it out that way.

 

[Jdeaton01]

It's got a 7 on the head but I know that's just so the manufacturers will know the torque specs

 

[smj999smj]

Yes, the "7" is a "grade 7T" in the Japanese bolt classification system. Knowing the bolt diameter, thread pitch and type of head along with the grade class will signify what the bolt torque is of the given bolt. I would think a trans mount bolt would be at least a metric class 10.9. You can probably order the bolt from Nissan, if you are not sure of the size or hardness. You don't tell us what year your truck is nor what engine/trans/drivetrain combination you have, so it's hard to be of much help.

 

[Jdeaton01]

99 frontier 2.4 automatic. Sorry about that

 

[Cusser]

If me, I'd use my left-hand drill bits and extractor to try to remove that broken part, not like it's rusted in place. And I'd use a tap to make sure the threads are OK.

If you can't get the broken part out, then it's "stuck good", so I'd just drill and tap back to the original size.

 

[Jdeaton01]

If me, I'd use my left-hand drill bits and extractor to try to remove that broken part, not like it's rusted in place. And I'd use a tap to make sure the threads are OK.

If you can't get the broken part out, then it's "stuck good", so I'd just drill and tap back to the original size.

Yea that's what I'm gonna do.. I got some 12.9 bolts I'm just gonna use them.