expedition vibes only when towing??

marty79

marty79

Well-Known Member
Joined
Dec 2, 2015
Location
Newton, NC
hey yall keep forgetting to ask before our next trip out soon.
Only when towing the rig, at 60-64mph front shakes pretty good. Before that all good and after it seemed to be good but didn't hold it past 65 long enough to really know (don't like going close to 70 pulling that weight on the half ton).
Driving everyday though no issues, no vibes, no wobble or shakes at all at any speed up to 94mph (did that for test purposes) so all is good empty but towing it does that?? Is that still in the front tires out of balance or am something in front end? Front end is all tight though which is why it's weird!!??
Tcase maybe?? (the torque on demand thingy??)

Currently the Transfer Case is gutted with just the main shaft locked in 2wd since it kinda blew up few weeks ago when it decided to shift into 4Lo on it's own while going 50mph lol (that was interesting).

So any thoughts on this would be great, thanks guys
 
Weight distribution is different when towing, so that includes a change in front end weight, and front ride height is likely also different because of that. So you're probably either having a front end geometry change, or something (that has always been there) is not getting damped because of either more or less vertical load than normal on the front end (should be less because of the bumper pull).
 
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Fabrik8 said:
Weight distribution is different when towing, so that includes a change in front end weight, and front ride height is likely also different because of that. So you're probably either having a front end geometry change, or something (that has always been there) is not getting damped because of either more or less vertical load than normal on the front end (should be less because of the bumper pull).
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ok sooo, what am I looking at? keep a little less weight off the tongue (maybe few inches back on trailer when loading)
it's hard to get everything level when I load it here at home since the driveway and the street aren't level and that's what I'm getting is the underlying issue if I'm understanding you correctly.

(now when I first went out with my landlords equipment trailer (heavy 2800lb empty) I don't recall dealing with this?!?! So, the extra weight and maybe position of the jeep on trailer was just right? We borrowed his trailer twice then started using mine once it was done) thank you and bare with me in understanding
 
Have you made any attempt at figuring out tongue weight? Probably almost everyone here is more knowledgeable about this topic than I am, but I'd be sure you have your tongue weight percentage in the right ballpark for safety and control. Don't change the tongue weight just to deal with the front end, else you may potentially end up with a poorly balanced trailer and a serious trailer dynamics problem.
 
Also, is the expedition stock (or lifted) and have you checked the alignment? If you're borderline with something like toe for example, the geometry/weight change from could be pushing you over that threshold and starting to oscillate.
 
Fabrik8 said:
Have you made any attempt at figuring out tongue weight? Probably almost everyone here is more knowledgeable about this topic than I am, but I'd be sure you have your tongue weight percentage in the right ballpark for safety and control. Don't change the tongue weight just to deal with the front end, else you may potentially end up with a poorly balanced trailer and a serious trailer dynamics problem.
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No I just always went how I was told years ago and never had issue till now.. load until rear squats a little and usually works well. I guess maybe load it and test around here then reposition and test again.
Front end is tight, allignment is good, actually really good
 
Expedition is stock on stock tires. Struts a little too soft otherwise all good.
 
Oh yeah it mostly only shakes when giving throttle not so much coasting down hills. Minor when coasting but under throttle at that speed was bad
 
marty79 said:
Oh yeah it mostly only shakes when giving throttle not so much coasting down hills. Minor when coasting but under throttle at that speed was bad
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Pinion angle Holmes

Think about what changes when you add all of that weight to the rear of the truck. What does that do to your rear driveline angle? I'd closely inspect the rear shaft universal joints and measure angle loaded vs unloaded.
 
So pinion angle in the rear would change would make the front tires Shake?? I'll double-check it but as far as I know the rear drive shaft is in good working order from the moment weeks ago on my transfer case blew up cuz I had to remove it but I'll double-check. Thank you
 
Another possibility...those trucks are notorious for erring towards positive camber angle issues.
Infact based on the entire geometry if you just jack the whole front end up just look at it.

So its possible, if not probable, that the camber is set a touch to the positive side. But the front end weight is compressing the suspension and balancing the camber. When you take weight off the front end while towing, you have less front end weight compressing the springs and flattening the contact patch out and you are riding around with a massive positive camber while towing.

The IRS on those is so damn soft that my son riding in the 3rd row of our 05 would cause steering feel changes. And for those that know my son, we sold the Expedition when he was 10! So its not what you are thinking.
 
Jody Treadway said:
Ate you sure it's the front shaking? Do you feel it in the steering wheel or in the seat?
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if I remember correctly it was more in the seat in the truck itself only a little bit in the steering wheel
 
Ron said:
riding in the 3rd row of our 05 would cause steering feel changes. And for those that know my son, we sold the Expedition when he was 10! So its not what you are thinking.
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Yeah this does suck pretty bad lol. I was thinking of picking up some of those coil spring isolators that go in between the Springs obviously not for off-road flexing but for the tow rig I was hoping it would stiffen up the Springs when they try to compress...thanks
I will check front end again.
 
Jody Treadway said:
If you feel it in your rear end, the vibe is coming from the vehicle's rear end
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Well it was definitely in front end like no mistaking that.
Now I don't have a transfer case anymore or a front driveshaft do maybe it had something to do with that. But definitely was not the rear diff or near the rear at all. Will check it all out and see if I find anything different. Thanks dude
 
I’d check tie rods and it could be possible that the tcase you have gutted has some internal damage such as bearings, that could be causing it. I dunno tho I know on my suburban when I have 10k behind it I have vibe bc of driveshaft angle change like jody said check Joints I’ve had a shake in what I thought was front and turned out to be bad rear axle!
 
marty79 said:
Well it was definitely in front end like no mistaking that.
Now I don't have a transfer case anymore or a front driveshaft do maybe it had something to do with that. But definitely was not the rear diff or near the rear at all. Will check it all out and see if I find anything different. Thanks dude
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You said the vibration was more in the seat than the steering wheel, if that is true then the vibration is coming from somewhere OTHER than the front.
Jody knows more than you so you should listen to him.
 
Alright I will check out entire suspension and drivetrain.. hopefully I find something obvious. Thanks everyone, I hope to get this figured out it's not good on wife with anxiety/panic attacks lol
 
I am agreeing with most. Tongue weight, forcing rear pinion up, also picking up the front, pinion angle may be going down. Under throttle, front it light, bring it up even more. So sounds like two driveshafts getting outa wack so creating a vibration. I solved that with my Suburban with some airshocks in the rear. Pump them up to about what it looks like when not loaded.
 
I'm starting to believe that I'm putting the Jeep too far forward and since the IRS rear is already soft, seems tongue weight just might be my issue. If all else checks out than that will be it.
 
So you got the proper opinions, & it's 1 end or the other! I think the easiest thing to do, is Load it, & play around with the position of the load, which will change the tongue weight. See if That affects the vibration, & if so, let us know which way stops it, or makes it worse. Won't cost anything to experiment!
 
Isn't that car IFS/IRS? The diffs are fixed. Pinion angle doesn't change.
 
marty79 said:
Yeah this does suck pretty bad lol. I was thinking of picking up some of those coil spring isolators that go in between the Springs obviously not for off-road flexing but for the tow rig I was hoping it would stiffen up the Springs when they try to compress...thanks
I will check front end again.
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Don't do this. You don't understand how irs works. You will button hook into a ditch at speed
 
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