Drive Line Vibration
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Joined: May 2001
Posts: 97
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From: boston,ma,us
Drive Line Vibration
Just curious, has anyone experienced any drive line vibration around 45, 65-75 mph?
I am second owner of 98 F150 SC SWB 4x4, XLT, OffPkg & TowPkg. It was 2 years old when I bought it and had the vibe. I've since then replaced tires, tie-rods, u-joints, did frt end alignment twice, flush tranny, change rear end fluid (w/fric mod) and got 4 wheels balanced. I still feel the vibe.
I don't think it it tranny because the vibe occurrs regardless of engine rpm or tranny gear selection. It always happens at the speeds noticed, even when coasting at 45 in neutral on the highway (engine rpm below 1000).
I want to say drive shaft, but there is no evidence that it has thrown any weights, and the three weights put on by the factory during balance (two on back end one up front) are still soundly attached. It now has 120K and I like the truck alot, but would prefer a "vibe free" ride while touring across country.
Any suggestions will be appreciated.
I am second owner of 98 F150 SC SWB 4x4, XLT, OffPkg & TowPkg. It was 2 years old when I bought it and had the vibe. I've since then replaced tires, tie-rods, u-joints, did frt end alignment twice, flush tranny, change rear end fluid (w/fric mod) and got 4 wheels balanced. I still feel the vibe.
I don't think it it tranny because the vibe occurrs regardless of engine rpm or tranny gear selection. It always happens at the speeds noticed, even when coasting at 45 in neutral on the highway (engine rpm below 1000).
I want to say drive shaft, but there is no evidence that it has thrown any weights, and the three weights put on by the factory during balance (two on back end one up front) are still soundly attached. It now has 120K and I like the truck alot, but would prefer a "vibe free" ride while touring across country.
Any suggestions will be appreciated.
Senior Member
Joined: Sep 2000
Posts: 178
Likes: 0
From: Norwalk, CA
I had the same problem! Fist I changed the u-joints at 80K I figure why not! $35 bucks this is EZ to change. But I still had the vibration also at 60 MPH. Well I gave my local ford dealer a visit and their mechanic told me to change the copper bearing on the output shaft of the trans! sounds like alot of work but its a cake job!
Parts & Part #'s you will need for the job!
*FZT7-7AO34-A BEARING $11.68
*F9TZ-7086-B PAPER SEAL $ 4.55
*F6TZ-7052-A END SHAFT SEAL $ 8.96
*1QT OF MERCON TRANS FLUID $ 1.49
How to repair...
1. Support the trans as you will need to remove the cross
member.
2. Remove cross member and trans mount.
3. Remove muffler support that connects to trans mount.
4. Discconect the spedometer sendor connector & remove it.
5. Remove the drive shaft.
6. The trans extension housing has 9 bolts holding it on remove
them and the part comes off.
7. You will be able to see where the new parts are going just by
looking inside of the housing.
8. Replace parts as needed and put back togethere.
Notes...
The 9 bolts that hold the housing get torqued at 25-30 foot
LB. and trans mount go at 85-90 foot pounds. The Qt. of
trans fluid is to wet the parts so that at first run you dont
run the parts dry. Check and fill trans to proper level as you
will lose about 1 qt. You do not have to remove the trans
pan to do this job! after everything is put back togethere
jack up the back end of the truck and support it with jack-
stands. Start the truck and put it in fist gear! Let the wheels
spin for about 10-15 minutes this will pump the trans fluid
back into that part. After that check trans fluid again and
your all set!! I know this sounds like alot but its not that
hard!!!! and for the price! the dealer wanted about 600-700
bucks for this job!
What did this fix solve!!!!!!!!!!
1. NO MORE "FN" THUNK!!!!!!!!!!!!!!
2. No more vibration at 60MPH
If anyone has question please ask! I cant tell you guys how mad i was when my truck had that THUNK every time I took off from a stop and then the vibration. I hope this helps....
Parts & Part #'s you will need for the job!
*FZT7-7AO34-A BEARING $11.68
*F9TZ-7086-B PAPER SEAL $ 4.55
*F6TZ-7052-A END SHAFT SEAL $ 8.96
*1QT OF MERCON TRANS FLUID $ 1.49
How to repair...
1. Support the trans as you will need to remove the cross
member.
2. Remove cross member and trans mount.
3. Remove muffler support that connects to trans mount.
4. Discconect the spedometer sendor connector & remove it.
5. Remove the drive shaft.
6. The trans extension housing has 9 bolts holding it on remove
them and the part comes off.
7. You will be able to see where the new parts are going just by
looking inside of the housing.
8. Replace parts as needed and put back togethere.
Notes...
The 9 bolts that hold the housing get torqued at 25-30 foot
LB. and trans mount go at 85-90 foot pounds. The Qt. of
trans fluid is to wet the parts so that at first run you dont
run the parts dry. Check and fill trans to proper level as you
will lose about 1 qt. You do not have to remove the trans
pan to do this job! after everything is put back togethere
jack up the back end of the truck and support it with jack-
stands. Start the truck and put it in fist gear! Let the wheels
spin for about 10-15 minutes this will pump the trans fluid
back into that part. After that check trans fluid again and
your all set!! I know this sounds like alot but its not that
hard!!!! and for the price! the dealer wanted about 600-700
bucks for this job!
What did this fix solve!!!!!!!!!!
1. NO MORE "FN" THUNK!!!!!!!!!!!!!!
2. No more vibration at 60MPH
If anyone has question please ask! I cant tell you guys how mad i was when my truck had that THUNK every time I took off from a stop and then the vibration. I hope this helps....
Senior Member
Joined: Apr 2001
Posts: 1,678
Likes: 0
From: Northern Kentucky
I'm not positive but I think Nacho;s fix would only apply to the 4x2's. Your's being a 4x4, your extension housing bolts to the t-case then the driveshaft so it's a little different setup.