Take off vibration (video)

[XLT and me]

Thank you for posting the video by the way Commbubba19.

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[Alex Bedrosian]

now of course i can't find it on FB. I believe he was leveled in the front but that should not have an impact on driveshaft angles. Also unloaded and not towing. Just normal vehicle accelerating to 15mph.

I've noticed mine is worse when first driven but seems to dissipate some after a few miles. I can feel it more when turning vs straight. I have zero other vibrations up to 80mph unlike others.

Indeed my obvious next step is to take it to my dealer yet i fear they will put little effort into resolving the issue. Most dealers don't for things like this. The techs just replace parts.

I believe this video was of a truck was lifted in the rear as well that sent the pinion angle off by a few degree. I lifted mine in the front and rear and immediately had this issue, I have since lowed the rear back by half and now it is gone. I found this video and thread when I was looking for an answer.

 

[Alex Bedrosian]

https://www.ranger5g.com/forum/threads/vibration-at-take-off.2092/page-6#post-101157

 

[Alex Bedrosian]

https://www.ranger5g.com/forum/threads/truck-vibrates-off-the-line.6122/page-2#post-121562

 

[commbubba19]

Ok adding these pics from my phone so bear with me. The carrier bearing definitely feels soft. I can move the d/s up and down by hand. Though it’s not compressed as I’ve seen others.

I loosened the mounting bolts and found the assembly seems to be being pushed towards the engine bay. Notice the adjustment allowed for by the guide. I bounced the truck up and down and messed with what seemed to be it’s happy spot then retightened. I didn’t have time to go for a drive.

My d/s angles look pretty good too. Again completely stock '20 XLT FX4.

 

[commbubba19]

video of me messing with the bearing after loosening the bracket. I then put it back in what seems like where it wanted to be, bounced the suspension, then torqued.

 

[WLFPIR8]

lol, that was my video in the first post.

I never bothered to try and fix it YET. This was with a 3inch eibach lift kit. Happens between 8 and 14 MPH.

 

[Zaph]

@WLFPIR8 thanks for the video. @commbubba19 Awaiting your comments after you take it for a drive, having loosened and re-tightened the carrier bearing mounting bolts.

My truck doesn't seem to be as plagued with this vibration as some others, but I'm paying attention in any case. Maybe I'll make an adjustment and notice it gone.

 

[P. A. Schilke]

video of me messing with the bearing after loosening the bracket. I then put it back in what seems like where it wanted to be, bounced the suspension, then torqued.

Hi CB19

Will be interesting to see if the relaxing of the preload made any difference. Two piece drivelines are prone to this start up shudder. I am guessing you did not try to lube the slip yoke splines, eh?

PITA but you may find the slip yoke splines need some lube...

Okay ... bit of a back story...I was a very inexperienced new hire at Ford Light Truck and we were launching the SuperCab in response to Dodge's Club Cab.... Start shudder of the plant pre production builds exhibited noticeable start up shudder. Our engineering team was totally surprised, having "tuned" the center bearing mounting. So the onsite team tried making a flat shim that spanned the center bearing bolts and lowered the center bearing by about an 1/8". Several vehicles responded nicely, but other vehicles responded negatively. In the end, the vehicles were determined to be left alone as the frame variation by the frame supplier could not locate the center bearing to the critical location. So shimming became the tool of the field service engineers on problem vehicles. There is also pinion change on acceleration that can impact start up shudder.

To assess rear axle pinion effect, try a gentle acceleration and then an aggressive acceleration. If there is no start up shudder with the gentle acceleration and noticeable shudder on hard acceleration, then the rear suspension compliance might be the culprit.

Time to get the dealer and the Ford Field Service Engineer involved...

Good Luck

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

 

[XLT and me]

Looking forward to seeing your results. I'm on vacation next week, so i will have time to do some investigating myself. On the drive out to work tonight i was trying to pay attention to what was going on when it did it's little shudder. It seemed to come on right at the the time it skip shifted into 3rd gear. Almost feels like shifting a manual into too high of gear and the engine bogs briefly. I might try calling my nephew who is a big truck mechanic to see if he has any ideas since he works on vehicles with two piece driveshafts and bearings all the time. Not going to be an enjoyable experience for me though,as he is a big GM guy.

 

[JaysOnTheEDGE]

Looking forward to seeing your results. I'm on vacation next week, so i will have time to do some investigating myself. On the drive out to work tonight i was trying to pay attention to what was going on when it did it's little shudder. It seemed to come on right at the the time it skip shifted into 3rd gear. Almost feels like shifting a manual into too high of gear and the engine bogs briefly.

I noticed the same on mine today after i read this thread and all day while i was driving and i was trying to feel the shudder and it its slight. Tomorrow I am doing to try it with turning on the Tow/Haul button. since it doesn't skip 2nd gear with it on.

 

[XLT and me]

Good idea! i will try it tomorrow also and see what happens. It is just enough of a vibration to be annoying. I did also notice that when the auto stop is on that it doesn't vibrate every time, but with it turned off, it does it every time. It also doesn't seem to do it when turning hard right or left from a stop sign. Really weird!

 

[James Martincic]

I noticed it since my test drive. the Dealer said it was the turbo. I have a supercharger on my Saleen and it takes off smooth. It doesn’t seem to do it in sport mode tho

 

[commbubba19]

Update

went for about a 20 minute city drive today and will say after letting the carrier bearing kind of move to where it is happier seemed to help. I’d say about 50% reduced vibration. I can tell it is if I lower the visor it used to vibrate quite a bit at that speed. Today less so but still there.
Unfortunately it’s so slight that I doubt I’d get any where with the dealership and I think I can live with it.

I’m of the opinion though that the carrier bearing in my case still has a side load on it due to either Not enough adjustment in the mounting bracket or the d/s length and bearing placement not quite being where they should. That side load could be causing a bind at lower rpms.

 

[P. A. Schilke]

Update

went for about a 20 minute city drive today and will say after letting the carrier bearing kind of move to where it is happier seemed to help. I’d say about 50% reduced vibration. I can tell it is if I lower the visor it used to vibrate quite a bit at that speed. Today less so but still there.
Unfortunately it’s so slight that I doubt I’d get any where with the dealership and I think I can live with it.

I’m of the opinion though that the carrier bearing in my case still has a side load on it due to either Not enough adjustment in the mounting bracket or the d/s length and bearing placement not quite being where they should. That side load could be causing a bind at lower rpms.

Hi CB19,

I think your next step is to lube the slip yoke splines on the drive shaft to see if this eliminates the side load...

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

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