home brew crossmember skid

foxwar71 · Nov 1, 2005

this is an idea i came up with for a tranny/TC skid based off the stock a stock crossmember. the two main crosses and the two side bars that span them would be either 1/4 or 3/16. on the two span bars, is 1/8 angle iron. the section covering the tranny would be removeable for serviceablitiy. the two half circles are tubin to cover the TC and cat. the middle would bolt into the original crossmember holes and the front two would be tapped or something. i was wonderin what all ur opinions on this setup would be. thnaks

RedBluff · Nov 1, 2005

Looks great.
How about putting some of that chopping board plastic under it too?

gearwhine · Nov 1, 2005

Why extend the crossmember forward...you aren't really protecting too much, but it won't really hurt anything either.

however, my complaint...if you're going this far with a crossmember, you should defintiely make it higher clearance than the stock one. An extra inch is a huge difference. _nicko_

Dirk Pitt · Nov 1, 2005

Drawn like that it looks like it will hang lower than stock.

If you are going to the trouble of designing something new why not improve the design? Make it mount as close to flush as possible with the bottom of the rails. It will be hard to do this forward of the stock crossmember because the transmission pan and exhaust is there, but it could be done with a little creative thinking.

Also, I know a few companies use the tube hoops to serve as a skid cantilevered off the crossmember but IMO, there are much stronger ways to do it.

HTH

What modelling program?

XJ_ranger · Nov 1, 2005

Dirk Pitt said:
What modelling program?

looks like solidworks to me

thought about front driveshaft clearance?

foxwar71 · Nov 1, 2005

this was my first rough draft so i could get a general idea and comments. i havent had a chance to get under my Xj and take all the measurements i need. i plan on makin it hang down less then the stock one and thinkin abotu changin around the front mount to somethnig that tucks around the framerails and is attached on the sides (hopefully elmiating tranny and DS problems). also, what would be some other ways to stiffin up the TC skid area besides a hoop? i more square area attached to that side rail too? thanks. i plan on makin some new adjustments.

RCP Phx · Nov 1, 2005

XJ_ranger said:
thought about front driveshaft clearance?

Ditto,my crossmember is modeled after a stock one but with a 3/4" drop built in.With nothing forward of that it just clears the DC joint when flexed.

davidt · Nov 2, 2005

what about a mount like this

or like this?

I like these designs better, and they seem to give more clearance, any opinions?

JeepZJlover · Nov 2, 2005

Heck with the kind of protection that last one gives might as well just put a thong under there

XJ_ranger · Nov 2, 2005

davidt said:
or like this?

I like these designs better, and they seem to give more clearance, any opinions?

that is a YJ though isnt it?

XJ_ranger · Nov 2, 2005

RCP Phx said:
Ditto,my crossmember is modeled after a stock one but with a 3/4" drop built in.With nothing forward of that it just clears the DC joint when flexed.

you run with an AW4 or an AX-15?

VegasAnthony · Nov 2, 2005

RCP Phx said:
Ditto,my crossmember is modeled after a stock one but with a 3/4" drop built in.With nothing forward of that it just clears the DC joint when flexed.

mayby its obvious ...but why did yoiu make a built in drop???

VegasAnthony · Nov 2, 2005

RCP Phx said:
Ditto,my crossmember is modeled after a stock one but with a 3/4" drop built in.With nothing forward of that it just clears the DC joint when flexed.

mayby its obvious ...but why did yoiu make a built in drop???

davidt · Nov 2, 2005

yup, that is a yj, but the exact same principle can be applied to an xj...

P.S. I like thongs

RCP Phx · Nov 2, 2005

VegasAnthony said:
mayby its obvious ...but why did yoiu make a built in drop???

My mounting allowed me to raise the crossmember 3/8" higher than factory.So I had to drop it(the center) at least that 3/8",so why not add a little more to ease the angles on the joints.Both XJ have HD SYE's so it really wasn't needed,but what the heck!
Ranger:both XJ's are AW4.

XJ_ranger · Nov 3, 2005

RCP Phx said:
Ranger:both XJ's are AW4.

thats why - with the ax-15 being about 2" shorter, the front driveshaft clearance isnt as big of a deal -

foxwar71 · Nov 3, 2005

here are some updated designs with a bunch of new changes, thanks to u guys.

i beleive the new design has resolved any clearance problems with the exhaust and front driveshaft while still protectin the tranny. the area under the tranny will either be removeable or one piece, either way is fine for me. which way u guys think? also, the rear half is modeled after the dpg TC skid and i made the sides rap around the rails for more support. ive also gained around half an inch or so by makin the total drop less then the stock crossmember. any other ideas on my skid design? thanks

davidt · Nov 3, 2005

what materials are you going to use? I like the design

old_man · Nov 3, 2005

The biggest design issue I see is the bolt arrangement. By putting the bolts on the out sides of the frame rails, you are not using the bolts in the shear mode. If you hit the bash plate, the force is trying to pull the bolts out. Some of the hits I have taken on my bash plates would have pulled the bolts right out of the frame rail. Not trying to bash a nice design, but experience says you need a stronger bolt arrangement. Maybe a plate on the inside of the frame rails and bolts that go all the way through, with some spacers in between. That is kind of hard to do on the drivers side due to the fuel and brake lines.

gearwhine · Nov 3, 2005

old_man said:
The biggest design issue I see is the bolt arrangement. By putting the bolts on the out sides of the frame rails, you are not using the bolts in the shear mode.

???? the basic idea here is they are in pure shear. If the skid plate is built rigid enough, you would only have to deal with shear. If you are sitting on a rock in the middle of the end of the t-case/cat skid, then it could bend the skid plate and cause the bolts to want to pull out. I can't really see that being a problem if there is a small brace put at the end of the plate, rather than using the plate as it's only source of integrity.

Through bolts are a given.... plates or very large washers on the inside as well. The inner spacers aren't a big deal if you dispearse the force wide enough.

My thought is how you're going to build this...? it's a pure solid right now. forgetting about the front part....how will the rear skid attach to the crossmember? Do you have a break to do the bends? as it's modeled now, building that the exact way it's shown will be very very difficult.

home brew crossmember skid

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