Drivetrain rattle/vibration

Topic: Drivetrain rattle/vibration (Read 2929 times) previous topic - next topic

Drivetrain rattle/vibration

April 21, 2008, 01:05:25 PM

70 mph and up and I get a rattle/vibration that comes all the way up into the shifter (shift actaully rattles on the handle kinda loud). At times (most often accelerating and cornering - even at lower, surface street speeds) it sounds like a loose shock where it bolts to the lower mount, but its not. I'm 95% sure my wheels are properly balanced. What else could this be besides the driveshaft needing a balance? Axle bearings (no grinding)?

Drivetrain rattle/vibration

Reply #1 – April 22, 2008, 10:57:38 AM

No one? Dang. I'm lost. Got the car up the back right now. Everything is tight: shocks, quads, sway bar, ride height adjusters, driveshaft bolts, exhaust... I'm just hoping it's safe to drive...

Drivetrain rattle/vibration

Reply #2 – April 22, 2008, 11:33:35 AM

Hard to diagnose remotely.

How is the driveshaft? U-joints?

Do you just feel it in the shifter, or does the whole car shake?

Drivetrain rattle/vibration

Reply #3 – April 22, 2008, 12:30:08 PM

Oh, right. I forgot to say, the U-joints are brand new and I'm 95% sure nothing got clocked during reassembly.

I feel it in the shifter around 80+ (pretty normal traffic flow speed on my way to work) and around 70+ I feel it in the left rear not the entire car.

Drivetrain rattle/vibration

Reply #4 – April 23, 2008, 11:47:33 PM

Did you mark the locations of everything as you took it apart? Meaning, is the d/s on the diff exactly where is was before? 95% sure of having everything "clocked" right is still giving yourself some room for error, so I am gonna guess that you did not mark anything when you replaced the u-joints, and if the vibration started after the u-joint install,.......there is a good place to start. How old are your shocks? The only way to tell directional vibration is if it is in the front wheels, which you will feel in the steering wheel, other than that, vibrations can travel though a unibody car and play hell with your mind. Start with the wheels and tires, then double check yourself on the d/s assymbly, then start looking at shocks and suspension components. Check the tires for bubbles in the tread as well, a seperated tread is bad news.

Drivetrain rattle/vibration

Reply #5 – April 24, 2008, 07:56:00 AM

Quote from: slowfoxbird;215490

Did you mark the locations of everything as you took it apart? Meaning, is the d/s on the diff exactly where is was before? 95% sure of having everything "clocked" right is still giving yourself some room for error, so I am gonna guess that you did not mark anything when you replaced the u-joints, and if the vibration started after the u-joint install,.......there is a good place to start. How old are your shocks? The only way to tell directional vibration is if it is in the front wheels, which you will feel in the steering wheel, other than that, vibrations can travel though a unibody car and play hell with your mind. Start with the wheels and tires, then double check yourself on the d/s assymbly, then start looking at shocks and suspension components. Check the tires for bubbles in the tread as well, a seperated tread is bad news.

putting the d/s in phase is only applicable and critical on a two piece d/s such as a truck especially with a c/v joint. You cant
assemble our one piece d/s's incorrectly.

Take the weight off one rear wheel
put the car in N
go up near the tailshaft and feel for play at the yoke.

if you find any play, go to my diy link and see what it takes to replace the $3.00 tail shaft bushing.

Drivetrain rattle/vibration

Reply #6 – April 24, 2008, 11:09:39 AM

Yes, I marked everything when I did my u-joints, but the extra 5% could be chalked up for anything else that may have distracted me during reassembly. Also, the vibration was present before the u-joint change.

Shocks are 2 weeks old, rear tires are brand new. Front tires are at 70% and need to be balanced, but not so much that I feel anything in the steering wheel; it's all coming up through the shifter.

As for the bushing: what kind of play are you refering to? rotational play in the drivetrain or back and forth play (grabbing the DS and pushing left and right toward either car door)?

Drivetrain rattle/vibration

Reply #7 – April 24, 2008, 05:53:54 PM

I didn't look back through your posts but, didn't you just have a broken rear shock, a wheel come off and a centering problem on your rear? Something may be bent...maybe axle?
Also, try swapping your rear tires/wheels.
Just throwing it out there.
Jim

Drivetrain rattle/vibration

Reply #8 – April 24, 2008, 10:30:02 PM

Quote from: jcassity;215518

putting the d/s in phase is only applicable and critical on a two piece d/s such as a truck especially with a c/v joint. You cant
assemble our one piece d/s's incorrectly.

QUOTE]

Hmmm.... that is not what the Ford engineer that taught my NVH certification course said......

The play in the bushing that jcassity is referring to is anything excessive in the slip yoke where it goes into the transmission.

If what Thunder 306 said happened, then you definately need to look for a bent axle or something weird like that!!

Drivetrain rattle/vibration

Reply #9 – April 24, 2008, 11:07:00 PM

Quote from: slowfoxbird;215626

Quote from: jcassity;215518
putting the d/s in phase is only applicable and critical on a two piece d/s such as a truck especially with a c/v joint. You cant
assemble our one piece d/s's incorrectly.

QUOTE]

Hmmm.... that is not what the Ford engineer that taught my NVH certification course said......

The play in the bushing that jcassity is referring to is anything excessive in the slip yoke where it goes into the transmission.

If what Thunder 306 said happened, then you definately need to look for a bent axle or something weird like that!!

go ahead and share whatyou know cause i just cant see how you can get a one piece d/s out of phase.

the slop in the tailshaft bushing im talking about will have play up and down , left or right pushing on it,, not rotational.

I forgot about your rear mishap,,, i agree with those suggestions as well.,,, it cant be good when stuff flys apart.

Drivetrain rattle/vibration

Reply #10 – April 25, 2008, 01:22:16 AM

I covered all that. I swapped the MK7 axles for SN axles after the incident (wanted my original track width back to prepare for 10.5's). Everything else (centering issue and the vibration) were all present before the wheel came loose.

I'll try swapping rear wheels. For some reason, having rotational tires, I kept avoiding that... but a few miles can't hurt. Maybe I could even squeeze the 275/40's under the front for a few miles and see if that moves the issue to the front...

Drivetrain rattle/vibration

Reply #11 – April 29, 2008, 01:22:17 PM

What I know about on piece driveshafts is that the whole assymbly, from the slip yoke, to the rear is all balanced as an assymbly. THey dont just balance a big stick and hope that adding a slip yoke and wont throw it out of balance. That is why when you change ujoints, you should put marks on them so you can reassymble exactly the way it came apart without having to second guess yourself.

Drivetrain rattle/vibration

Reply #12 – April 29, 2008, 09:08:35 PM

this is my understanding as well. They even go as far to say you should mark the on the rear-end and bolt it up in the same position when reinstalling (in most manuals anyway).

Drivetrain rattle/vibration

Reply #13 – April 29, 2008, 10:31:59 PM

You are correct, because sometimes you can eliminate a driveline vibration by "re-clocking" the d/s to the pinion . Any Ford workshop manual will tell you to index mark the u-joint areas of the d/s. And if you want to get even more picky, your Ford workshop manual will tell you to mark your trans output shaft and the front of the d/s so that can go back as is was as well.

Drivetrain rattle/vibration

Reply #14 – April 30, 2008, 10:30:36 PM

Yeah, I did both... :D