Trailing Arms Crossmember driveshaft clearance question
 

Has anyone had to cut or crind on their crossmember where the driveshaft goes through after lowering their truck.

Went to pick mine up from the alignment shop and my driveshaft is rubbing pretty hard on the crossmember. Heading back up after work with a plasma cutter.

I thought maybe this is a common problem for people lowering their trucks 5/7 but I cant find any other threads about it.

Re: Trailing Arms Crossmember driveshaft clearance question
 

My 68 was dropped @ least 5/7 w/a 1 pc shaft (3.5"od?) & never hit in several years of daily driving (with & w/o a load)....

Re: Trailing Arms Crossmember driveshaft clearance question
 

I'd also like to hear some answers to this.

ksshane, is your driveshaft a one piece?

Re: Trailing Arms Crossmember driveshaft clearance question
 

ECE and Cpp I believe make a crossmember that has more driveshaft clearance as well as openings for exhaust so you dont have to run it under the crossmember

Re: Trailing Arms Crossmember driveshaft clearance question
 

5.5/8 drop with stock crossmember no problems.. 3.5" driveshaft..

Re: Trailing Arms Crossmember driveshaft clearance question
 

Well my issue was a little different... yes it was rubbing on the crossmember, but not because of the drop.

Had a friend help me with the flip kit, and it just so happen that when I went to return the ball joint tool to Oreillys he tightened down the u-bolts on the rear end. Well he didn't get them tight enough. The rear end was twisting causing the driveshaft to raise up. Once I figured out the problem their where no issues. My friend felt horrible... It was an honest mistake and it happens.

Re: Trailing Arms Crossmember driveshaft clearance question
 

Sweet deal!! Good thing you didn't cut.

Re: Trailing Arms Crossmember driveshaft clearance question
 

Now that you just finished your static drop it time to air bag it:devil:

Re: Trailing Arms Crossmember driveshaft clearance question
 

I always like repairs that dont cost money ........ !!!!!!!!! You have a leaf spring truck dont you ..?

Re: Trailing Arms Crossmember driveshaft clearance question
 

Yep.. running leafs.

On a side note... Tommy.. stop showing all those sweet wheels in the vendor classifieds.....lol Everytime I look at one of your posts I can feel my wallet getting lighter and lighter..lol

Re: Trailing Arms Crossmember driveshaft clearance question
 

hello ksshane. I had that same problem. I cut my cab n cross member. the thing is, I don't have the money to finish it rite now. for the front, I will install spindles and bags to complete my air bag suspension set up. my wife's birthday & Christmas are around the corner. I spent a lot of money on my truck this year. the kids and wifey gotta have my funds the rest of the year.

Re: Trailing Arms Crossmember driveshaft clearance question
 

You know I can't do that ....... !!!!!!! :lol::lol:

Re: Trailing Arms Crossmember driveshaft clearance question
 

Bringing this one back to the top.
Hoping there is more info now than when this thread left off. Read everal and found no answers.

I have a 68 LWB. LS/T56 Magnum swapped. QA1 rear suspension as low as it will go (7" drop?). Engine is @ 4 degree down towards rear.
I just got my 3.5" 1 piece DS made and it hits the top of the trailing arm crossmember before I can even get the DS in the rear yoke.

So my options are.....
I can cut out the top of the crossmember and build a loop up a few inches (2-3") or swap that crossmember for one that provides a good bit more clearance.
The folks who make the aftermarket ones don't show measurements to let me make a decision on which one will do what I need. Anyone here have one and willing to provide measurements from the top of the frame to the top pf the loop?

Re: Trailing Arms Crossmember driveshaft clearance question
 

The ECE style aftermarket T/A x-member is about ~1.5" taller than the original T/A x-member. It's un-modified here in these pics:

Re: Trailing Arms Crossmember driveshaft clearance question
 

You can mod the original one or go aftermarket. Either one can be raised as needed. You'll just need to verify clearances & modify as needed.
This is the ECE style x-member from the pic above that's taller than GM's original piece. I raised it an additional 2" so it's about 3.5" taller than an original x-member hoop:

Re: Trailing Arms Crossmember driveshaft clearance question
 

Thanks. I am leaning towards mod'ing the stock unit. No reason to buy something just to cut it up. May as well use what I got and hope I don't need to remove it to get it done.
Thinking about using some flat 1/4" or so by 4" plate shaped as needed and welded in. Then cut the top of the OEM unit out. I think some triangle gussets would help on the sides where you extended it. Surely can't hurt.

Looks like the cab is gonna need a trim as well.

Re: Trailing Arms Crossmember driveshaft clearance question
 

6x-66 cabs have more clearance @ the back of the cab vs. 67-72's so more than likely it will be needed. You also need to make sure about the driveshaft OD for its length to make sure the critical speed crossover point isn't breached.

Also.... Depending on how low it gets & because it has a longer wheel base, the bottom of that x-member might need to be modified as well since it dips lower than the rails @ mid frame.

Re: Trailing Arms Crossmember driveshaft clearance question
 

I ended up mod'ing the stock crossmember.
I extended it up to give 4" more clearance than stock.
Then my driveshaft didn't clear the bottom of the cab. I had to notch the square brace (think it was there for support of the tank?) that runs along the bottom of the cab. Anyway, notched it up to the floor of the cab and then cut the back wall of the cab to match. Used a 5" hole saw for this. Clamped a 10"x10" section of plywood in place that had a 5" hole in it to use to locate the saw. worked perfect.
Got about 3 fingers room @ static ride height. Hits the bump stops before it hits the cab.
No issues @ full droop. Not even close to contacting.
Did all this w/the cab and bed (no floor) in place.

Re: Trailing Arms Crossmember driveshaft clearance question
 

That brace is the rear cab brace & not just for the gas tank. I would gusset the brace the same amount removed (or close to the amount removed if using thicker material).