[CaseyP]

i searched here...really didnt find anything...browsed mcmaster....didnt find anything either...

i need a way to attach my crossmember/skidplate/ whatever the fuck you wanna call it for the trans/tcase on my tj. problem is that i cant find a decent way to run the bolts up into the frame. im using 8 7/16 bolts on each side. any ideas?

 

[paulkeith]

couple ideas:

run the bolts all the way up through the frame, sleeve the bolts, and put the nuts on top (that'swhatshesaid)...

or add an "L" shape to each side of the crossmember/skid so you can drill through the short dimension of the frame. The added benefit of this route is you get the bolt heads up out of the rocks.

either way, if you drill through the frame you're going to want to sleeve the bolts to keep from crushing the frame with any kind of torque on the mount bolts.

i've never seen a TJ frame in person, but you might be able to just fish nuts into place and just bolt it up, but i doubt it. this makes repeated removal and re-installation ridiculous too, unless you could tackweld them in place.

good luck
Paul

 

[iroc86]

On my YJ, the Jeep engineers welded 1/2" nuts to the inside of the frame tube to hold up the crossmember. The TJ is probably similar, and this design is plenty strong. In fact, I'm using these factory bolt holes for supporting the transmission and transfer case in my diesel driveline, all of which weighs in excess of 1500 lbs. Sleeving the frame would certainly be ideal, but I don't think it's going to make much of a difference. These are static load points and do not see changing forces. On the other hand, your power steering pump holes are probably sleeved through the frame. There are much greater (and dynamic) forces at work and the sleeving definitely helps reduce stress and fatigue.

I like Paul's idea about using an L bracket and bolting through the minor frame dimension.

Just curious... is this a custom crossmember? Any reason why you didn't reuse the factory TJ mounting location?

 

[microtus]

There are a ton of builds, and photos, that have shown different mounting methods for a crossmember and or skid plates.

I searched crossmember +method in the Jeep hardcore section and had 7 pages come up. A couple of threads down was this.

Without looking back at it I believe it was for a crossmember, though I've seen similar for skids as well. Hope it helps

 

[CaseyP]

On my YJ, the Jeep engineers welded 1/2" nuts to the inside of the frame tube to hold up the crossmember. The TJ is probably similar, and this design is plenty strong. In fact, I'm using these factory bolt holes for supporting the transmission and transfer case in my diesel driveline, all of which weighs in excess of 1500 lbs. Sleeving the frame would certainly be ideal, but I don't think it's going to make much of a difference. These are static load points and do not see changing forces. On the other hand, your power steering pump holes are probably sleeved through the frame. There are much greater (and dynamic) forces at work and the sleeving definitely helps reduce stress and fatigue.

I like Paul's idea about using an L bracket and bolting through the minor frame dimension.

Just curious... is this a custom crossmember? Any reason why you didn't reuse the factory TJ mounting location?

im aware of what jeep did.....the stock crossmember is a stock piece of shit...that i have no desire running...this is a dedicated trail rig, gettin a dbl tri 4 link rear and a 3 link front. its a crawler, so low with as much ground clearance as possible, hence the flat belly.

this will also be the platform for mounting the links as well.... and i really dont trust 6 1/2" bolts. i am also planning on sleeving and bolting through the side of the frame as well. i want a solid mounting platform that i dont have to worry about when im on the trail.....

 

[iroc86]

The stock crossmember does what it's designed to do. But it's certainly not suitable for mounting suspension pieces; I was not aware that's what you were doing. (You never mentioned anything about a flat belly until now, too). If you're seeing loads like that, why use 7/16" mounting hardware?

With these new details, putting bolts in both directions through the frame (shear and tension) seems like a good method. Sleeved, of course.