Ford Repair: Rear vibration, monroe sensatrac shocks, ford f150 supercab

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Flag this messageAllExperts Reply to your questionSunday, September 27, 2009 7:38 PM
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QUESTION: Hi Chris, Thanks for taking the time to answer my question. I own a 2002 Ford F150 Supercab, 4.6 l engine 2 wheel drive, short bed. It has 84,000 miles. It has had a vibration that is felt in the seat and floor of the truck for quite some time. I have replaced the shocks a couple of years ago. I always thought that the vibration was from the tires. I recently replaced with BFG Long Trail TA Tours and had them road force balanced. The shocks have been replaced with Monroe Sensatrac shocks. I have replaced all the brake rotors and pads with Wagner Thermoquiets. I have had the driveshaft balanced at a driveline shop. My vibration is felt at about 36-42 mph and then returns a high speeds such as 55 and above. It is speed dependent, it is felt when coasting in neutral. The roatation rhythm seems to be with the speed of motion. I recently reindexed the driveshaft and the rear end. It seesm to have decreased yet is still there. What do I do next to repair this annoying situation?

Thanks,

John

ANSWER: hey there, i need to know one thing.does this truck have a hanger bearing on the drive shaft???  let me know
Chris P

---------- FOLLOW-UP ----------

QUESTION: No hanger bearing. It is a long single drive shaft.

John

ANSWER: hey there again, well there can be a few items that can cause a vibration. does the engine possibly have a misfire under lad?? but if this is a vibration when speed icreases, try having the drive shaft balanced, Local dealers will be able to tell you where to go to have this done, cause believe it or not the drive shift has to be balanced just like a tire would have to be balanced. If this doesnt solve your problem let me know, good luck
Chris P

---------- FOLLOW-UP ----------

QUESTION: The driveshaft was balanced. A small amount of weight was added to the rear of the shaft. No "crazy wild" driveshaft per the driveline company.
Thanks
John

Following is the reason:

hey there, give me a VIN number and i will run this truck on our inford sight to verify there is no idd ball proplem with this truck, i can see alot of service history from this sight. ill let you know within a day thanks

1FTRX17W12NB61739

Thanks

Answer
hey again.
unfortunatly, there are no technical service bullitins on a rear end vibration on these trucks according to Fords technical website. there is a listing for a possible Clutch pack shutter if this truck is equiped with a locking differential.(it more than likely is equiped) If the fluid has never been serviced try that as your next step. You MUST use the ford full synthetic  diff fluid and the friction modifier that is sold only by Ford dealers. If this doesnt help then this looks like it may be a complicated problem that will have to be traced down by process of elimination. Ford dealers can use chassi ears and other specific tools to pinpoint where this is coming from. Let me know what happens.
good luck
Chris P