continuing vibe, new soap opera "As The Drive Shaft Turns" , help please

[geepaw]

Ok guys,

I had my drive shaft replaced this week (with a new ford part #)
and the vibe is still there at ~ 61MPH. I have previosly replaced the
rear pumpkin assy due to the pop. I even had a whole new crate
motor installed after 4 mos of owning it for the tick (& you wonder
why I have'nt done a pully or whipple). $40K & vibe are not
adding up in my head.

I have new 18" AFS w/Toyos so I know it is not the tires (as I had
the vibe with the f1's). I want to go to C/O's, but want this fixed
first so Ford can't blame it on that.

What else is there to do to get rid of this?
Thoughts/advice welcome.

 

[05 Roush]

If you are getting vibration at those speeds, it's most likely caused by 1 of 3 problems:

1. A bad rear pumpkin. I had 3 rear pumpkins ordered and replaced before one was "in tolerance".
2. A non-concentric clutch. If your clutch pedal pulsates, your engine runs rough, or your clutch shimmies, you need the clutch aligned/replaced.
3. A bad halfaxle. This can be caused by a twisted or leaky CV joint.

If you listen closely, you may notice a super low frequency drone at around 45 MPH. If this is the case, it's a halfaxle. A whine at ~65 MPH from the rear indicates a pumpkin that's out of tolerance.

Hope this helps!

 

[Rice Eatr]

The pop, can you tell me a little more about that please. I had the whole rear assembly and DS repaced due to the vibe. The vibe is now gone but now once in a while if I stop at a stop light or sitting in traffic I hear a pop sound which sounds like it is coming from the rear.

 

[geepaw]

The pop, can you tell me a little more about that please. I had the whole rear assembly and DS repaced due to the vibe. The vibe is now gone but now once in a while if I stop at a stop light or sitting in traffic I hear a pop sound which sounds like it is coming from the rear.

my pop was during hard acceleration or going around a corner....the
rear poped or clunked

 

[geepaw]

If you are getting vibration at those speeds, it's most likely caused by 1 of 3 problems:

1. A bad rear pumpkin. I had 3 rear pumpkins ordered and replaced before one was "in tolerance".
2. A non-concentric clutch. If your clutch pedal pulsates, your engine runs rough, or your clutch shimmies, you need the clutch aligned/replaced.
3. A bad halfaxle. This can be caused by a twisted or leaky CV joint.

If you listen closely, you may notice a super low frequency drone at around 45 MPH. If this is the case, it's a halfaxle. A whine at ~65 MPH from the rear indicates a pumpkin that's out of tolerance.

Hope this helps!

I have a new pumpkin assy...maybe 5k on it.

Also, my exhaust is not stock, so I would'nt be able to hear the drone
you are referring to.

thanks for the info! :beer:

 

[Steeda30]

I have a low frequency pulsating humming sound coming from the rear at speeds below 65 or so, it sounds like tire noise on an old Suburban or something. Is that a half axle? Mine vibrates in the 60-65 zone, guess that's the driveshaft or?

How much is it to replace the half axles?

 

[05 Roush]

I have a low frequency pulsating humming sound coming from the rear at speeds below 65 or so, it sounds like tire noise on an old Suburban or something. Is that a half axle? Mine vibrates in the 60-65 zone, guess that's the driveshaft or?

Driveshaft vibration tends to cause noise while in gear and usually goes away or gets 100% better under no load. If yours vibrates in neutral, it's most likely flat spots in the tires, or a bad halfaxle. Start with doing a road force balance on the tires followed by a check of the halfaxles.