Topic: Budbuild Crossmember - Question

[jimbo74]

In theory, the difference between hot and cold rolled steel is hot is rolled to its final dimensions while it’s hot enough to scale (1700 degrees F+) while cold is rolled well below scaling temps

Cold rolled steel is usually the better stuff to have. But, hot is rolled while hot, so it has a chance to normalize after the last rollers, it pretty much is stress free. Cold rolled steel actually work-hardens in the rolling process. Meaning that it gets stronger towards the end after you work it for awhile and its ductility decreases.

[budbuilt]

Hi All!

Just to clarify, this guy was using a dual case crossmember with only a single case and mount.  That puts a lot of stress way out on the tail, where the second case normally is bolted to.  Since nothing was out there to support it, and it hangs lower than the rest of the crossmember due to the drivetrain slope, the rear twisted upward on impact.   Perhaps the original poster could change the title to say that his friend failed to put the second case in! 

BTW, the tcase damage was internal stuff, NOT related to a bent crossmember!   


And we form them cold like everyone else.  Heating steel to bend it is a great way to weaken it.  Hot rolling is used to manufacture the steel, not parts.  Cold rolled plate is not available and would be VERY nasty due to all that flaking scale. 

See ya out there!
Bud   

[blackdiamond [OP]]

Budbuilt,

I updated the thread title to sound less negative.  I know your products are quality and my intent wasn't to "dog" your products.

I would agree that the t-case problems would be difficult to blame on the cross member bending (I'm sure this is why Marlin Crawler is providing parts for the repair), but I'm amazed at all the problems that seemed to happen all at once.  My buddy seems to have the worst luck of anyone I know with broken/failed parts, especially considering that he doesn't abuse his truck.

 

I have not personally seen the set up he was running, but I'm not sure how having dual cases installed would make the installation stronger.  The crossmember should direct the load into the frame even if there are no t-cases installed.  I know that he used some spacers that might create some stress points, but I'm not sure why one vs. two cases would make a difference.

 

[blackdiamond [OP]]

My buddy just sent me an email clarification.  They thing the rear differential failed due to a reused crush sleeve prior to him getting the truck, the rear driveshaft looks like "normal" wear and tear, and if I understood him correctly, the t-case problems didn't involve the output shaft so they all seem to be unrelated issue that all happened at once.

 

[budbuilt]

Thanks for the help there blackdiamond!    We appreciate it! 

>I'm not sure how having dual cases installed would make the installation stronger.

Consider having a large aluminum housing and a steel and rubber mount bolted to what your friend had as an unsupported piece of steel and I think it will be clearer! 

>The crossmember should direct the load into the frame even if there are no t-cases installed.
 
Correct!  But, mount only one up front on the weakest portion of the crossmember and then land the truck on the rearmost, unsupported section and it could bend!  The dual case crossmember MUST have the arms that attach it to the frame cut away ( at least on the driveshaft side) for driveshaft clearance.  That makes the front portion of the crossmember only cantilevered from the rear, more supported part.  Add the weight of the tcase and driveline up front ( think like on the end of a diving board ) and you have the worst of all worlds.  If you jump on the other end of the diving board where it is supported, you would never bend it. 

Disappointing for sure, but very explainable. 

Bottom line is that your friend now has a single case crossmember, (2nd day air!) that is straight across and supports a single case much better.  It has no cantilevers or notches for driveshafts and will work the best for a single case.  Getting the right part for the application is important. 

Does that help make it more clear?

Thanks all for the interest and the place to explain. 
Bud   

[blackdiamond [OP]]

I know that when he purchased the dual crossmember from you he purchased some spacers to allow it to function with a single case installed.  Will you continue to "market" this option or will this experience cause you to just say NO!

I ran a single case on my Marlin Crawler crossmember for several years without a problem, but maybe I just got lucky.

[budbuilt]

Good question...   
We have shipped 187 of those spacers in the last 5 years.  Many were used to make the old trail gear crossmembers work without rubbing so can't tell exactly how many guys run that setup or for how long.  This is the first issue that we have ever heard of tho.  We do it as a customer service so you don't have to buy one crossmember when you run single cases and then another when you swap to duals but maybe we should take the money twice?     NAH!
Probably will still offer it as an option.   

[blackdiamond [OP]]

Maybe just a warning to let people know that there is a weakness with the setup (not the crossmember).

Thanks for being willing to discuss your product with us! 

[CTENG in KS]

I have not personally seen the set up he was running, but I'm not sure how having dual cases installed would make the installation stronger.  The crossmember should direct the load into the frame even if there are no t-cases installed.  I know that he used some spacers that might create some stress points, but I'm not sure why one vs. two cases would make a difference.

 

With the second case installed the drivetrain acts as a stiffener to help alleviate the out-of-plane loading on the crossmember.

If you do not have the second case installed the rear of the crossmember becomes an unsupported cantilevered beam.  When it is loaded up it transferes a large bending moment right to the crossmember mounts (where it bent).

[Duffil]

Thanks for clearing that up Bud!  Glad to see you straightening us out.