Before I can get to work on ho-made TJ long arms, I gotta' do something about the gawd awful belly draggin' factory T-case skid/mount.

So here's the plan.

http://pages.prodigy.net/coolmank/pics/misc/x-member.bmp

The aqua bar across the middle is 1/2" x 4" stock. The red pad in the middle represents a stock TJ tranny mount. Yes, there are four countersunk through holes under there to accept the four studs in the mount. The holes are countersunk so that the accompanying four nuts don't protrude below the 1/2" bar stock.

A la':

http://pages.prodigy.net/coolmank/pics/misc/x-member3.bmp

... and ...

http://pages.prodigy.net/coolmank/pics/misc/x-member2.bmp

Ahh, smooth, like a freshly shorn sack ... of potatoes!

The green brackets are nothing more than 3"x3"x0.250" angle iron or what's left of my old bumper. *Snif* I loved that thing so! The brackets will get welded to the frame rails and the 1/2" x-member bolts to the brackets with 7/16-14 FHCS's. I'll even tack the nuts down to the brackets to facilitate installation and removal.

You may notice that I have the frame rails drawn parallel when in fact, where this is all going to take place, they are not. Don't worry, I got it covered. I just didn't feel like getting quite that anal about my drawing.

I should have all this completed by the 17th. Then I can begin work on the long arms. Once all that is done, as much of the underside as possible will be plated with completely flat 1/4" sheet. Not flat like a Currie skid or a flat like a Tera skid. Not even flat like RE's long arm skid. I'm talkin' flat like my first ... well ... hey, she was 18 at least! Gimme' some credit.

Any of you pukes see any flaws in this idea?

cmk

I just finished a very similar thing on my Xj this afternoon, I used the same 3X3 1/4" angle but I ran it on the outside of my 'frame' and welded it everywhere it touched. And I used a 1/4" plate instead of 1/2" and it works realy well. (you might want to think about this cause you have more welding surface area, I ran 3 ...1/2" bolts up through the 1/4" plate through the 1/4" angle and through the 'frame' and I can say it is very solid and you only loose 1/4" of clearance) I also made a TC plate and braced the 1/4 inch crossmember with some angle iron 1.5" 3/16 wall where clearance wasn't a problem. also mine was about 8" front to back (there were some relief cuts to clearance the exhaust and the front driveshaft but I love it.


Just some more ideas but I see no problems with your setup either especially since you have a more solid frame than the unibody XJ

MY only Concerns would be for the transfer case, and maybe the front driveshaft. T-case might be alright though with the 1/4" sheet. But I still worry that the front driveshaft might hit on that x-member. Check out http://www.jeepshots.com/tech/skid.html to see how someone else built theirs (however no long arm when the x-member was installed)

Originally posted by DEnd
MY only Concerns would be for the transfer case, and maybe the front driveshaft. T-case might be alright though with the 1/4" sheet. But I still worry that the front driveshaft might hit on that x-member.

1/4" with the proper support will stop anything including yo' mamma's gas attacks. So I ain't worried about the case.

Say it with me now ... "Beano."

And where that 1/2" x-member falls is directly below and a schoche behind the front d-shaft yoke. Therefore, there ain't no way the front shaft will hit it. Unless of course I physically remove the front shaft and beat it against the x-member.

cmk

CMK

I wonder if this will be sturdy enough. Maybe it will be ! Do you have any other support besides this crossmember?

The reason I say this is because when I installed my RE crossmember, which seems really beefy, I noticed a slight bow in it after all the weight and stress was placed on it.

I'm not saying it won't work, I'm just thinking out loud. Did you do this on a CAD stress simulator or what?

Originally posted by orbitcat
I'm not saying it won't work, I'm just thinking out loud. Did you do this on a CAD stress simulator or what?

No, it's not worth the time and effort to run this through FEA.

Keep in mind, this is purely a transmission mount. There won't be any suspension being mounted to this.

cmk

O.K. I got ya!

My opinion is it will be more than strong enough. I just went through the hole tranny mount thing and mine works fine. This will be at least half again as strong mine is.

CMK-

I don't know what tcase and xmission you have, but you might consider the shifter linkage from www.advanceadapters.com if you still have a 231. Also, how much body lift do you have? It will be fun to push the cases up that high without 2" or so. What about the motor mounts? I would go 1.5-2" up with them? You probably have thought of all this, just some ideas.

-Bart

I just did something similar.

Check out my wrenching progress post. There's a pic.

I used channel that was about 4-5 inches wide, with a 1.5 inch lip for the crossmember. And I used some rectangular 2x1 for the part that sammiches it to the frame. Works out pretty well.

I don't doubt its sturdiness, but I'd be a little worried about the lack of skid protection with a strip that narrow...You don't want any large boulders getting up in there and cramming your vitals! :D ..JMO

EDIT: Also, while I'm sure the 1/2" would support your junk with no problems, if you drop it onto rocks enough times, I would bet that it would start to bow upwards, even 1/2" thick. Just not enough surface area to distribute the impact, it's all focused in that narrow strip.

We"Icouldbetotallywrongbutitsoundedgoodtome"lby

Sorry, just felt like doing the quotation thing :D

I'm sure that CM(putting a dumbass message in his name)K is intending on putting together a separate skid, and that this is just for the crossmember.

Right?



heh heh... I said member.

Just re-read and noticed his skid plan.... Oops.

Like someone mentioned before...I would used channel steel. You can flip it so that it looks like a "U" and would have the same thing...but you can use thinner steel and have more rigidity. Even 1/2 steel may bend;)

Originally posted by Scout Dude
Like someone mentioned before...I would used channel steel. You can flip it so that it looks like a "U" and would have the same thing...but you can use thinner steel and have more rigidity. Even 1/2 steel may bend;)

I'll second that... (called increasing the moment of inertia in engineer speak)

bart,

1" body lift and 1" motor mounts. Yes, I will need some *minor* body work under the center console area. I'm hoping that I can get away with just reshaping it a little versus cutting any holes. Then again, those that know me know I have no problem cutting holes in my floor.

... case in point:

http://pages.prodigy.net/coolmank/pics/gtl/shocks.jpg

I think I also found what you are referring to on AA's site. Do you mean the T-case shifter linkage that bolts directly to the case's flange? If so, that may come in VERY handy. Thanks for the info.

Mo & welby & even Scout Dude,

I'm sure you guys saw it by now, but yeah, the entire underside will get plated with 1/4" that will be well supported. I haven't figured out all the mounts for it yet since I still haven't entirely figured out exactly where all the long arms will end up. The 1/4" will also get reinforced with plenty of vertical ribs. All said and done, that 1/2" bar plus the 1/4" against the bottom of it, plus the reinforcements should be roughly equivalent to a 1" bar. If I bend that with a 4k lb. Jeep, I'm gettin' it! And we don't do that often here in the Midwest.

cmk

Im not sure it would be strong enough but do you plan on drilling and tapping the 1/2" at the frame connection or are you going to use studs. I know you only lose a little with a nut or a bolt but if your going for smooth why not totally smooth

arndog

Originally posted by cmk
bart,

Then again, those that know me know I have no problem cutting holes in my floor.




Cutting?? You want cutting, talk to the aptly named "Cutter"...That guy's gone cut crazy! Bwwwwaaaaahahahahaaaaa :evil:. Last I've seen, he chopped his TJ in half! *

* Slight exaggeration.

Originally posted by arndog
Im not sure it would be strong enough but do you plan on drilling and tapping the 1/2" at the frame connection or are you going to use studs. I know you only lose a little with a nut or a bolt but if your going for smooth why not totally smooth

arndog

Recheck the pics ... albeit they might be a bit confusing to some. The 1/2" bar is held to the angle brackets by means of countersunk flat head cap screws which means that absolutely nothing hangs below the bottom of the frame rails.

cmk

The only things you made need to look at are:

1) The cat. This may or may not be in the way.

2) The transmission mount is not parallel to the ground. I have my tranny up to the floor, and did a "custom" tranny mount as well to run a flat skid. All I did was cut out the angled section of the factory skid plate, to ensure I got the angle correctly. But this can be solved by changing the angle of your bar spanning the frame rails. I can't be sure because I never actually did a design like that, but I think you may want to keep the tranny/t-case at the same angle, to prevent any undue stress on the both the crossmember and the driveline.

3) As already mentioned about the t-case shfiter, I would be willing to bet a case of beer that when you push the tranny up to the tub, the t-case shifter will not work. The angle on the bellcrank is very severe. I bought the AA part to relocate on the bellhousing, it worked great but you may need to modify it a bit (remove some material) to keep it from hitting the body.

When I put on my flat skid, I drilling the holes out through the frame all the way up, in order to run a long ass bolt and nut, instead of relying on the pansi threads/nuts/crap tack welded to the inside of the frame rails. Makes it much easier and stronger.

The OE cat will *barely* clear. Once all is said and done, the entire exhaust is getting replaced including a Random Tech. 4" tall cat. With the new cat being 4" tall, the frame rails being 4" tall, and a 1" body lift, I should be in the clear, including the 1/2" thick member under the cat.

You're right about the tranny mount, if I follow what you say. I will be keeping the 1/2" member flat with the frame rails to facilitate mouning the 1/4" plating to it later. The entire powertrain sits as a slight downward angle (front to rear) so the trany mount wil be at an angle as well. I thought about machining a swath of the 1/2" bar to match that angle, but I think that's more trouble than it's worth.

I'm just gonna' bolt the tranny mount to the flat member, in effect "tweaking" the rubber mount slightly. I'm keeping my fingers crossed that it wil be alright. I guess I'll know for sure if I start tearing through tranny mounts. If so, then I'll rethink that machined section. Otherwise, I want to keep everything as simple as possible to get this up and running ASAP.

cmk

I would add some type of lip on either side of that 1/2 plate to add strength. I just built a tranny crossmember for my jeep and used tubing, it worked out well and is totally under the frame rail, but I don't think that would work with a ax-15.


http://www.admotorsports.com/jeep.org/cjl-tj/02-05-02/P1010004.JPG

CJ

Hey! I've got another Idea for you to consider. I just did a totally flat skidplate on my YJ, and did it a little different than you. The rubber mount thingy is pretty thick, so you have to lift your t-case up higher to get the flat skidplate on. I mounted a peice of flat stock directly under the t-case (bolted right on, no rubber thingys under it at all). Then I welded on some flat stuff on the sides of the bottom peice with lots of gussets for stiffness, so I have now made a U shaped "cradle" for the t-case. Then I welded some tube to either side of the cradle and welded some bushings to the ends of the tube and made some bushing mounts on the insides of the frame rails for them to bolt to. Did all that make sense? Basicaly if your rubber tranny mount is about an inch tall and you used 1/2 plate all the way across my t-case will be 1.25 (cuz I used 1/4 inch plate directly below the t-case) inches lower, but still have a perfectly flat skidplate (mines also 1/4") bolted directly below the frame. This way you will get better driveline angles and you will have to do a lot less modifying of your floor. My floor required no modification. Let me know if that makes sense or if I need to explain it better. Unfortunately I have no pics.

Originally posted by Welby



Cutting?? You want cutting, talk to the aptly named "Cutter"...That guy's gone cut crazy! Bwwwwaaaaahahahahaaaaa :evil:. Last I've seen, he chopped his TJ in half! *

* Slight exaggeration. Hey Welby!:D Your right, here's how ya cut a hole in the bed of a TJ:flipoff2:
http://dkg.elmo-the-dog.com/pictures/medium/1013315887.65.66.106.88.jpg

Now I know that working on your jeep can give you a hard on...but at least use a towel or something! :rolleyes:

Originally posted by crawlinTJ
Now I know that working on your jeep can give you a hard on...but at least use a towel or something! :rolleyes: LMFAO!!! :laughing: :laughing: :laughing: :laughing: didn't think anyone would notice...:emb:

Cutter, I do hereby succeed (sp?) to you. My grinder shall forever have a complex now.

Ghetto, your idea is exactly what I was originally going to do. I don't know if a TJ tranny mount sub plate is identical to a YJ's or not, but with the way the TJ's plate works, reusing the stock tranny mount is not all that bad. But yes, if I did it your way, I would be able to keep my T-case about 1/4" to 1/2" lower than the way I am going to end up doing it.

For simplicity's sake, I'm going to stick with the 1/2" bar idea. Like Lagos suggested, I will try and weld some reinforcement strips to the 1/2" once I know where I can do so.

cm "thanks for all the input guys" k

Originally posted by crawlinTJ
Now I know that working on your jeep can give you a hard on...but at least use a towel or something! :rolleyes:

ROTF... That was good!

I ditched the factory skid and trans mount infavor of a solid trans mount w/ 2 point wrangler bushings on the ends of a tube crossmember. Covers the almost flat idea and destroys the chance of over torquing the motor mounts.

GhettoRig, I like your idea, It took a minute to understand what you were talking about, but now that I do it makes perfect sense. I am in the process of designing a flat, or relatively flat skid for my TJ because I am putting in a Flipped dana 300, which will allow me to remove my TC drop and raise the Skid close to flat without driveline angle problems. I am not sure whether or not I am going to clock the case or not, depends on the shifter position. I think I may incorporate a similar mounting method, I was even thinking of making it adjustable by having that mounting plate kind of float on 4 bushings which would be munted on threaded rod so the could be raised or lowered as needed to match the angle of the case. Might be more complicated than neccesary though.

PS, if anyone is considering doing a dana 300 flip kit in a TJ or YJ, now is the Time! Down East OffRoad is offering their flip kit for only $550 as part of a group buy, ends this week though, so e-mail me if you're intersted.
iluvsnow@usa.net

Adjustability is cool... My rear coils are adjustable for height so i can level the thing when they sag to one side (not that it helps much since the thing just leans whichever way I turned last). I used this method to raise my t-case (along with a 1" engine lift) and it allowed me to just cut a skidplate out of a big ass peice of 1/4" and bolt it flat with the bottom of the frame. I don't think I will have any driveline angle problems, but I did push my rear axle back ten inches, so that might have helped.:D