rear end vibration in 98 F150

I have a 98 F150 2 wheel drive. When I reach 60 mph I get a vibration coming from the rear end. As well, when I brake, the rear end shudders. The u joints are good, the rear brake shoes and drums are new. There isn't any noise associated with the vibration such as a squeeling or grinding. I wonder if it could possibly be an axle bearing even though there isn't any noise ?:banghead:

Has one of your wieghts popped off your driveshaft. I know if this happens you can get a bad vibration.

does the truck have a midshaft bearing or carrier bearing(depends on what part of the country you live in by what it is called) If you have a midshaft bearing getting alot of slopp in it then it will give you vibrations at certain speeds. Automatic or staight shift?

No, I have checked the driveshaft and the weights are still there.

It is an automatic and has a solid shaft.

I have pulled the backplate off of the differential to check things out there. Everything looks good. About the only thing I haven't really had a look at are the axle bearings. Because of the lack of any noise, I have just figured that they were probably alright. Now, having checked out everything else that I can think of, I'm thinking about pulling them.

I forgot to mention, that the rear end shudders when I let up on the gas and decelerate as well as when the brakes are applied. It sure has me puzzled and to say the least frustrated.

Hey Brent
Check your ujoints to be sure theyre ok. Look for signs of rust powder or metal coming from the caps. Take the rear joint loose and pop the caps off and wiggle the joint, check the front one also. They can get dry of grease and the bearings start coming apart and cause vibration even though they feel tight when you try to move them. Also, you mentioned new rear brakes and drums. Did the vibration exist before you had this done? Ive had problems with some of the aftermarket(chineese made mostly) drums being out of round/balance , and also had a few that were bad castings where the drum interfered with the wheel not letting the wheel seat flat on the axle flange. If the ujoints are ok, jack it up and put it on jack stands, run it up to the speed where you get the vibration and check the wheels/driveshaft for wobble . Also check the pinion shaft for play, there would usually be a noise associated with this but not always.

Hello Ed. The U joints are new and the rear brakes were done well after this vibration started. The drums and shoes are all North American made.
I have also noticed that lately the vibration, especially when braking, becomes more pronounced after the truck has been driven for a bit and things have warmed up.
I really appreciate your input. I am still puzzled by it, but am continuing to look at everything I can to hopefully locate the problem and finally eliminate it.

I had a similar vibration re my 2001 F-150, 4.6 L automatic, 101,000 Miles.
Removed the driveshaft and found the tail shaft housing bushing/bearing to be worn allowing the driveshaft to wobble. I replaced the bushing/bearing and seal. This alleviated the vibration.
Make sure you check the yoke that slides into the transmission, the part that rides on the bushing/bearing, for abnormal wear.

Plese post your findings.

Sorry for the delay in getting back to you. I was just wondering, did you change the tailstock bushing yourself. If you did, how did you go about removing the old one and installing the new one ? Also, did you have a lot of side to side play on the driveshaft yoke giong in to the talistock of the transmission ? If I push side to side on mine, it seems to move quite a bit.

Thanks

Brent

I supported the engine and removed the tailstock and took it to a transmission shop for replacement of the bushing/bearing and seal. He also put the yoke on the lathe and dressed the yoke a couple thousands. Any more than a couple thousands, you will have to replace the yoke. Hopefully your bearing/bushing is worn and not the tailstock or yoke.
Some of the big transmission shops will not sell the bushing. Look for a small shop.
Sounds to me that you need a replacement.
Let's us know what you fine.

I repair crown vics for the state patrol and have had that problem many times. ITs always an axle bearing, usualy by the time I get the car too much damage is done, and require the whole rear end to be replaced. but the cars that are fixable make a loud whining noise coming from the differential after having the bearing replaced. this is caused by the debris from the bearing that basicaly destroyed the diff. Shops will never tell you this because they want you your money and alot of it. If they can make it a costly repair for you they will. Cheak under the brake drums after its been warmed up to see if it is slowly leaking sometimes you have to take the brake drum off. When you get new diff. fluid get "royal purple" in the recommended weight it cost more but i've seen a great decreace in breakdowns after switching all the cars to their products.