Drive shaft grinding on gas tank skid?

[wfo9]

Spent part of today resolving this. I think I got it, but will have to get out and fully flex tomorrow to verify.

The pictures show the modifications I made to the skid and the bracket.

The first pic shows the grinding that was still happening after my first attempts.
The second one shows the first cut I made, plus the section I took out today.
The third one shows the top of the bracket and where I cut it. The hole needed to move about 1" towards the front of the truck.
The fourth one shows what the bracket looked like after I welded the tab on to the other side and drilled the new hole.

One thing not shown in the pics is that I also had to take off a 1/4" on the rear most edge of the lower part of the bracket to keep it from hanging out past the aluminum. I could have forced it to line up when bolting it up, but I wanted the top of the bracket to be 100% flat and not stressed.

I sure hope this resolves it because it was a bit of a PITA to resolve.

 

[wfo9]

Put it all back together and went out and flexed it. Still hit the edge right near the carriage bolt. So I cut off another inch. Have not tested yet, but this better do it. It's been a real PITA to have to keep dropping it and re-install... Have tried to be conservative on the trimming... and you just can tell until you get it out in some crazy positions.

I did not take any pictures this time, but the attached shows the approx cut line now. Hoping 3rd time is a charm. plus the bolt is as far back as possible now.

 

[Okki]

I can also readily reproduce the issue on my driveway now. I thought it was the grease port on the trail arm, but it looks like I'll be trimming my shrockworks skid this coming weekend.

I'll post my findings and trimming details here.

Okki

 

[wfo9]

I can also readily reproduce the issue on my driveway now. I thought it was the grease port on the trail arm, but it looks like I'll be trimming my shrockworks skid this coming weekend.

I'll post my findings and trimming details here.

Okki

I was able to eliminate most of it with the first round of trimming. I'm now down to only have issues at extreme flex. My setup is probably different than most in that it allows for serious stuffing of the rear wheel. It's long travel without any loss of up travel. I'll eventually run different shocks and extended the bump stops and that will probably eliminate the issue.

Here is a quick pic of how suffed my tire can get.

 

[4RBob]

sorry if i missed it in the thread, but have you measured from frame to tire/wheel on both sides. maybe an adjustable panhard would resolve the remaining issue at full flex?

 

[wfo9]

sorry if i missed it in the thread, but have you measured from frame to tire/wheel on both sides. maybe an adjustable panhard would resolve the remaining issue at full flex?

Good point, I should measure for a sanity check.

The other thing going on is that I have a slightly bent passenger side LCA. That could be causing some odd axle movement at full flex.

I'll try to test out my latest setup today. But even if it grinds, I'm not going to mess with it. I went ahead and ordered the rest of the MT setup yesterday. So I will have new LCAs with the ICON shocks and the extended bump stops.

The "on the cheap" setup I did initially actually worked really well overall, but I did not anticipate how low my bumper would get at full flex. It could almost drag the ground at full flex on flat ground in that corner. So, I figured more up travel and less down travel (the 3" bump stop extensions...). Should help all around.

This truck is starting to get to be an expensive toy. Think I have dropped almost 7 k into it now.

 

[wfo9]

Quick update on this. No more grinding or contact after last cut of the skid.

Axle also seemed to have correct track at ride height.

I'm about to put the MT ICON LT shocks on the rear (replacing the procomp #926514, so the equation will change again, but there should be less potential for contact since I will be basically trading out 2" of up travel for 2" of additional down travel.

 

[wfo9]

I had this issue resolved, but after going to 34" tires and removing the rear sway and really flexing it out with the drivers side tire stuffed (like in the attached pic), the contact between the drive shaft and gas tank skid is back.

It's not as bad, but it is definitely happening. My theory is that the wider track allowed me to flex it more and now that the control arm bushings are loosened up, it is hitting again.

There is not much more I can do besides grind it down a little. I've cut away about as much as possible.

I might try to widen a few of the holes so I can shift the skid over a bit more to the drivers side, but it is about as far as it can go. The actual shaft is hitting now. There is a small weight or something on the shaft and I can see where it has made contact with the skid, but the U-joint is the main contact area now. I could just leave it alone, but I hate noises.....

 

[wfo9]

One more attempt to stop the grinding. I was going to try a a different panhard bar.. but since I only seem to need a few more mm of clearance (and I'm happy with the way the truck performs on and off road). I decided to fabricate a new bracket and trim the skid a bit more. I hope this take care of it.

I cut a little window in the skid where the driveshaft weight was. So if it does rub, it should not not make so much noise. I also bent the remaining rear tab inward a little to gain a bit more clearance in that area.

The change in bracket design requires two carriage bolts on the bottom, but it is back near the diff anyway, so I typically don't slide in that area..

Hope this solves it for good. It Took me several hours to get all the angles on the bracket just right.... I put gussets on both ends just to make sure it was not going anywhere.

This off-road stuff has forced me to beef up my metal fab skills. Can wait to show off my next project. Need to knock it out before next weekend so I can get out and enjoy this thing.

 

[Xtremluck]

One more attempt to stop the grinding. I was going to try a a different panhard bar.. but since I only seem to need a few more mm of clearance (and I'm happy with the way the truck performs on and off road). I decided to fabricate a new bracket and trim the skid a bit more. I hope this take care of it.

I cut a little window in the skid where the driveshaft weight was. So if it does rub, it should not not make so much noise. I also bent the remaining rear tab inward a little to gain a bit more clearance in that area.

The change in bracket design requires two carriage bolts on the bottom, but it is back near the diff anyway, so I typically don't slide in that area..

Hope this solves it for good. It Took me several hours to get all the angles on the bracket just right.... I put gussets on both ends just to make sure it was not going anywhere.

This off-road stuff has forced me to beef up my metal fab skills. Can wait to show off my next project. Need to knock it out before next weekend so I can get out and enjoy this thing.

[MENTION=106176]wfo9[/MENTION] did your last chop do the trick? I'm experiencing the same thing at full flex off road and was planning on hacking up my skid to fix. Would prefer to do the job once and have a general sense of how far back I need to cut (Thanks to you!) but would like to leave as much protection on as possible. My skid has done its job a few times over!

 

[rochmpr]

[MENTION=106176]wfo9[/MENTION] did your last chop do the trick? I'm experiencing the same thing at full flex off road and was planning on hacking up my skid to fix. Would prefer to do the job once and have a general sense of how far back I need to cut (Thanks to you!) but would like to leave as much protection on as possible. My skid has done its job a few times over!

If you go through my build, I documented my fix for this issue. I also recently swapped to a new Double Cardan shaft which gave me a bit more room, a very little bit.

 

[Xtremluck]

If you go through my build, I documented my fix for this issue. I also recently swapped to a new Double Cardan shaft which gave me a bit more room, a very little bit.

Thanks man super helpful. Adding this to the list of fixes before the next trip