Transmission crossmember studs

[DirtyComanche]

Anyone have a good (not junkyard) source for the studs that are used to locate the transmission crossmember?

 

Dorman 03124 seems to be the right size, and they're stamped as a 10.9.

[AZJeff]

17 hours ago, DirtyComanche said:

Anyone have a good (not junkyard) source for the studs that are used to locate the transmission crossmember?

 

Dorman 03124 seems to be the right size, and they're stamped as a 10.9.

That rating should be plenty adequate for those fasteners intended job.

[DirtyComanche]

56 minutes ago, AZJeff said:

That rating should be plenty adequate for those fasteners intended job.

Yeah, the factory bolts would have only been a 10.9 at best.  They don't have a stamping on the head that I'm used to though, I think it's just a letter F.

 

I think I'll just order a set of those Dorman ones and see if they work.

[DirtyComanche]

So, just in case anyone searches and finds this, do not use those Dorman studs.  I ordered them without being able to see them, so you get what you get, and it's not acceptable for this application.

 

There is no stampings on them to indicate strength, and the package labeling is very generic but calls them a "Grade 5".  A grade 5 is more or less equivalent to 8.8, which is okay, but not ideal, but since there is no such thing as a metric grade 5 fastener the whole thing is highly suspect.

 

Each end:

 

Packaging:

 

I didn't check if the nuts were brass or not.  They are black, but there is a hard black coating used on brass (I assume it's an oxide coating) that looks similar to that.  Regardless, the package is just generic BS from what I'd guess.

 

But the real damning thing is the thread form:

 

I'm guessing this thread is used for applications where there is extreme heat cycling as it would allow the fastener to expand and contract more without stressing it.  I could be totally wrong about that, as I'm not familiar with this thread form.   I do believe it is intentional as I ordered two packages and they are all like this.  Regardless, it is not a proper load bearing thread as it is rolled with a very narrow crest and a wide root.   I would not trust this stud in any sort of application where the failure of it would ruin your day.

[DirtyComanche]

Next question...

 

If I drill the threads out of my captive nuts, can I tap to 7/16 UNC?  It looks like there's lots of meat there.

 

The issue I've had that leads to this is that the threads in some of them are not great.  A stud is better for this scenario in that as long as you put it in correctly it will never wear the threads out more, hence why I was just going to use them and call it good.  I'm taking the crossmember on and off multiple times as the whole drivetrain has been in and out and whatnot a bunch.

[JustEmptyEveryPocket]

20 hours ago, DirtyComanche said:

If I drill the threads out of my captive nuts, can I tap to 7/16 UNC?  It looks like there's lots of meat there.

I did this on my truck. Has held up fine for a few years and some abuse. *shrug* YMMV.

[DirtyComanche]

47 minutes ago, JustEmptyEveryPocket said:

I did this on my truck. Has held up fine for a few years and some abuse. *shrug* YMMV.

It's probably what I'm going to do then.

 

I likely could just get away with leaving it, but yeah...  Rather not.

[AZJeff]

The weld nuts in my frame were mostly trashed, so I opted to drill/tap to 7/16 UNC.  It worked out fine, but a word of caution:

 

those weld nuts in the frame are HARD.  It took me an average of 10 minutes per hole to drill and tap with cutting oil.

[DirtyComanche]

13 hours ago, AZJeff said:

The weld nuts in my frame were mostly trashed, so I opted to drill/tap to 7/16 UNC.  It worked out fine, but a word of caution:

 

those weld nuts in the frame are HARD.  It took me an average of 10 minutes per hole to drill and tap with cutting oil.

I'll be prepared for that then.  I generally hate hand drilling things above my head.  

[JustEmptyEveryPocket]

9 hours ago, DirtyComanche said:

I generally hate hand drilling things above my head

Well, lift the truck up a foot or two, then sit on a mechanics seat beside the truck and leverage the drill off your knees. Much less effort required and easier to support for long durations. Plus, no metal fragments falling onto your face, eyes, in your hair, etc.

[DirtyComanche]

1 hour ago, JustEmptyEveryPocket said:

Well, lift the truck up a foot or two, then sit on a mechanics seat beside the truck and leverage the drill off your knees. Much less effort required and easier to support for long durations. Plus, no metal fragments falling onto your face, eyes, in your hair, etc.

I actually can drill most of them from the top...  maybe all of them.  Pending my decision on the passenger side floor.