I had the opportunity to speak with an Engineer on the suspension team for the 2006 MY F150. After discussing our business I asked him on a personal note if he knew anything about the "vibration" issues at hand with the 2004's.

He told me that he just joined the F150 program for 2006 MY and was not involved in the 2004-05 MY's, but he did have some indirect involvement with the problem. He stated that in HIS OPINION... not FORD MOTOR COMPANY's... the problem could be cured with 100% proper rear axle driveline angles. He commented on the fact that the lift blocks on a 4X4 between the axle and the leaf pack have no taper to them; they are the same size in the front as in the rear. On most OEM lift blocks and every aftermarket lift block I have ever seen there is a built in taper to the block to keep the rear axle at the proper angle as you lift the vehicle.

I know that 4X2's do not have the lift block, but he seemed to beleive that the problem was in the angle where the rear axle meets the leaf pack with or without a lift block.

For anyone experienceing the vibration problem and is willing to try anything I would suggest replacing your factory lift block with an aftermarket lift block that has the built in taper. If you have a 4X2 they make correcting shims that are tapered as well. The problem you guys may run into is that the new F150 uses a two-pin leaf pack; every other truck I've seen uses a single pin. The problem is that you'll need a aftermarket lift block drilled for two pins and I haven't seen any yet.

Another test could be to goto your local auto parts store and buy some cheap air shocks for $50 and install them on the rear. Using the air shocks to adjust the ride height will also change the angle of your rear axle. Do a trial and error test at different heights. When and if you find the vibration goes away then measure the angle of your driveshaft and the bottom of your rear axle housing. Take this measurment to a auto shop that will be able to machine this angle into your lift blocks. Your best bet would be a high performance shop that deals with suspensions... they do this type of thing often.

Good luck.

 

If the problem was that simple, would not Ford, with a vast R&D department, been able to affect the cure with a $20 fix?

Who knows, but one can bet that your engineer friend might realize mucho $$$ from stuffing a note in the Suggestion's Box.

 

I believe this shimming of the rear axle has been tried many times for this problem.Shimming the driveline is covered in all auto repair manuals and special angle gages exist for this purpose.It seems to me after reading 800 post about this vibration that there are several different vibrations and no one fix is going to repair them all.

Just my opinion.

Mike

 

Well I work for Ford myself and I wouldn't be surprised.

 

I talked with my dealer again today... He said he spoke with his service manager abou the vibe, and he said it was an issue with the F-150s built in 03. They had a 'major headache' with those, but it's since been corrected. SSSoooooo... anyone with a truck built in 04 with the 'vibe'?

EDIT: Oh yeah, he also said the vibe issue was with the front end... not the rear, driveshaft, wheels/tires, etc...

 

So can you provide us with more information from this service manager that seems to know about the vibe?

Can this dealer post some answers?

 

I have the vibe nd my truck was built in April 04. I just bought it last Monday. My vibe is at its worst from 40-60. I feel it from 20+ but it is bearable.

 

I'll grill the guy some more on my next visit... hopefully this week to pickup my truck!!!

 

can you ask him what the proper angles should be?