Stripped Transmission Crossmember Bolt, looking for suggestions (2 Viewers)

[ReformedJeeper]

Hi Guys,

I installed Marlin Gears a few weeks ago and in the process discovered one of the transmission Crossmember weld nuts inside of the frame rail is stripped (FYI I have an IPOR skid plate) Additionally, the PO had broken off the other bolt in the frame rail already. So I'm down to 2 bolts on one side instead of four. I'm looking for suggestions here, because I don't think drill and tap will work well with a weld nut, just not sure if there is enough metal there. I'm thinking of a couple of options:

1) weld the Crossmember to the frame. This undesirable because it makes getting the Crossmember off more difficult (I did install the marlin gears myself and I've never done t case work before, who knows how long it will go without having problems)

2) try and do a drill and tap. As stated above I'm worried about not having enough metal on the existing weld nut.

3) somehow cut a window into the frame and fish a bolt down... cutting the frame just seems scary.

Any suggestions are welcome. Real world experience is even better.

Thanks

 

[LINUS]

This came up a few years ago for a friend, I cut a window (2 holes connected, so a "figure 8" when both drilled) in the frame with a holesaw & welded in a new nut. I've been welding for quite some time so I was very comfortable doing it.

After the fact he asked a few places if there were any other real options & the people he'd asked would have advised as I'd done, so blind sqirrels do find nuts.

I backwelded the slugs the holesaw cut & hit it with some paint - I wasn't out to hide anything, just backwelded to keep out crud.

I'm not a collision repair guy, just been welding awhile & worked refineries - plenty of guys are welding their sliders on, so I don't think our frames are heat treated & stress relieved like say a tractor / semi frame (you don't weld on those).

 

[jeffro109]

I'd try to tap it before cutting the frame. If you can get the current welded nut out of the way, you could also try a new nut with a piece of wire welded to its side to position it through an existing frame hole if one is nearby while you tighten the bolt in.

 

[nukegoat]

Tap with 1/2-20

 

[Brentok]

Tap with 1/2-20

I did this. Can't remember the size but that's probably it-- SAE size bump worked well.

 

[Hornd]

Drill then tap then coat new bolt with Anti-Seize.
I bet that nut is hard as crap, as it's likely Grade 8 or 10.
Take your time, and wear glasses, since fixing eyes makes mechanical work look cheap.

 

[UTkruzer]

Tap 7/16-20 and you won't have to drill, at least the stripped one and you'll have plenty of steel remaining. The 10mm stripped hole is just about the correct drill size. Just take it easy and back the tap out often. The broken bolt is another thing.

 

[Alleycats]

Sorry for the highjack, but a relevant question. What is the thread size/pitch of the OE trans. crossmember bolt? I'm missing one and need to replace.

 

[UTkruzer]

Sorry for the highjack, but a relevant question. What is the thread size/pitch of the OE trans. crossmember bolt? I'm missing one and need to replace.

M10x1.25 30mm long
FYI-Bolt Size for Transfer Case Cross Member

 

[Alleycats]

Cool thanks.

M10x1.25 30mm long
FYI-Bolt Size for Transfer Case Cross Member

 

[ReformedJeeper]

Thanks for the suggestions. I'm going to try to tap the hole this weekend. I'll let you know how it goes.

 

[ReformedJeeper]

Thanks to UTkruzer. I used your suggestion on the stripped bolt and it seems to be working fine. I didn't bother with broken one, I figure 3 out of 4 is good enough, flame away.

 

[69LC]

I just used a 7/16-20 tap in my one bad frame hole and seemed to have gotten good threads. Thanks to whoever shared that.

 

[FamilyCamper]

just replaced my rusty crossmember. Had one bolt with stripped threads. Thanks so much to everyone who went before me in this thread so I was able to get all the correct parts.

 

[Rusty Marlin]

Just went through this myself.

I bought an M10x1.25 helicoil kit from NAPA.

https://www.napaonline.com/en/p/BK_37109

Worked great and exactly as advertised.

 

[PIP]

Helicoil is the way.

 

[FamilyCamper]

Just went through this myself.

I bought an M10x1.25 helicoil kit from NAPA.

https://www.napaonline.com/en/p/BK_37109

Worked great and exactly as advertised.

Oh that is a cool tool!

 

[FamilyCamper]

Helicoil is the way.

You are able to reuse the washer from the stripped bolt if you cut the end of the bolt off. I had to drill the hole out a bit to fit the larger diameter replacement bolt.