Do I need a crossmember? (1 Viewer)

[BELMONT148]

I was under the rig tonight taking of my parking brake drum to send to Jess @ HAD, and I noticed that I do not have transmission crossmember. Is this necessary?

I have a 71' FJ40 and someone else put a 2F and 4 speed tranny in it. They cut out the tubular crossmember that gets in the way when you do this swap, and I did not know if they just stopped with it or if it is not needed. I was looking at this one as an option, but if it is a waste of 2 bills then I won't bother.

http://eshop.advanceadapters.com/commerce/catalog/product.jsp?product_id=1811

Also, this will only support the drivetrain. Do I need another support to keep the frame from flexing, or is this not needed?

Jeremy

 

[rusty_tlc]

Nothing supported the 2F/4Spd when my 40 was stock except the rear engine mounts.
I cut the tubeular crossmember out to make room for a toy box.

I have heard it called a torsion tube and that it is supposed to limit frame twist.

At any rate I had a new, longer, one made up at a fabricator for $40. I relocated it far enough back to allow instal/removal of the t-case/toybox in one unit.

All I did was bring the fab shop the old part and ask for another exactly like it but three inches longer on each end. I cut it to fit when I installed it.

 

[BELMONT148]

I did a little more searching and found conflicting opinions. It seems Steve (Poser) likes the mount and Mark doesn't. See thread:

https://forum.ih8mud.com/showthread.php?t=77966&highlight=speed+crossmember

So, what to do? Mark says it adds stress to the soft case.

But I still wonder what to do about the tubular crossmember. I am going to have to mount the shackle for my traction bar to something, so I guess I should just plan on building one for that.

Jeremy

 

[LC_Hamma]

Mark says it adds stress to the soft case.

The tubular crossmember is freestanding with no mounts to catch the tcase. I feel if you have a *sufficently built skid plate, not the stock one, that eliminates the twisting the crossmember used to prevent.

 

[Mark W]

My comment was probably about the crossmember that is used in most V8 installations to support the back of the engine/tranny/Tcase by bolting to the rear of the tcase.

The factory torque tube does not have anything to do with stress on the Tcase.

It would probably take a skid plate that was pretty stout and more importantly prety strongly bolted in place to prevent frame flex.

I've seen rigs operated without the torque tube. Just general all around use, not dedicated full on rock crawling. Never noticed any problems from it.

I would lean toward replacing it anyway. I'd make one out of heavier material so as to provide a better anchor point for any anti-wrap bar you might choose to install in the future. And I'd move it back a tad for easier removal/installation of the tranny and Tcase if need be.


Mark...

 

[BELMONT148]

Thanks for the clarification Mark, but I still did not understand if the mount for the transfer case was needed. I am going to make a strong crossmember in the rear, but will I be o.k. with letting the case hang?

This will be a rock crawling rig. And I will be using the stock skid plate until I can afford one of Lance's at IPOR.

Jeremy

 

[Mark W]

The T/C hung from the factory. Most T/Cs do. Cruisers and other makes. Normally the mount is st the belhousing, or under the tranny, or the adapter between the tranny and T/C.

There is no need for a crossmember attached to yout T/C. The only reason folks put them in is becasue they have done a V8 swap and a crossmember attached to the rear of the T/C is the simlst way to support the new drivetrain. It also subjects the T/C to stresses it is not designed for.

Since you have a 2F and factory 4 speed, you have absolutley no need for this item.

Move along now. break it up, nothing to see here folks.


Mark...

 

[theo]

Move along now. break it up, nothing to see here folks.

Mark...

lmao

 

[BELMONT148]

Thanks for the help Mark.

Jeremy