I am going to do my best to explain this. I have a 96 150 2 wheel drive super cab. I bought it recently and I'm trying to get it on the road.
First problem: When you put it in drive and begin to roll, there is some sort of thumping or vibration you feel and lightly hear. I can't tell if it is coming from the front or rear. I thought it was the front passenger side but the more I listen the more I'm confused. It starts as soon as I start moving and increases with speed. I haven't even taken it over 30mph b/c I'm afraid something is going to snap. I have put it in nuetral while rolling and it is still there. I jacked it up and grabbed all four tires and tried to shake them etc. thinking it may be a really bad wheel bearing. No movement. However, in the rear on both tires, if I grab one and pull on it, it will move out slightly. Looks like the entire drum etc moves out, and then you can push it back in slightly. That is on both sides in the rear. I may be stupid but is that normal? If not then what is wrong. If it is, then that's not the problem.
It's not really a vibration like you would get under load with a u joint etc. The "vibration" is there no matter what speed, in gear or out, under load or not, turning or going straight, etc.
All input and help will be greatly appreciated.
I will put the other issue in another post when I fix this one.

Thanks all.

 

Wheel and/or axle bearing? Maybe you can get it in the air (or jack it up) and shake/spin one wheel at a time. Seems like if it was something with the drive shaft, you'd feel it in your feet also. I'd try the simplest first and spin each wheel. Reading farther down, it sounds like you've got a hub/axle bearing going bad. I don't know enough to comment on the movement you mention, but it doesn't sound like a good thing.

Good Luck

 

Thanks for the reply
I put it up in the air yesterday but I didn't notice any movement that would indicate a bad bearing. It is so bad that I figured one of the bearing wore out and was tearing up the spindle. However, no movement when you shake the wheel or spin it.
Could it be a bad tire?
I'm not sure about the drum moving either.

 

The drums will move in and out slightly. I am guessing you have an 8.8 and what you feel is the movement out until the "U" washer hits the side gear. Going in the axle hits the pinion shaft.

The "U" washer:
http://i54.photobucket.com/albums/g91/subford/Rear%20End/8-4.gif

The Pinion Shaft:
http://i54.photobucket.com/albums/g91/subford/Rear%20End/8-3.gif

 

[QUOTE=subford]The drums will move in and out slightly. I am guessing you have an 8.8 and what you feel is the movement out until the "U" washer hits the side gear. Going in the axle hits the pinion shaft.


Great reply. Thank you. That clears that part up. I'm thinking maybe I have a really bad tire. The tread is good, but maybe a bad belt etc. Not sure what else it could be. I just don't feel any movement in the tire indicating bearings. It was this way since I picked it and I haven't driven it anywhere besides around the block since I picked it up.

 

The drum moving is normal, like subford said, but it can be deceptive rolling them in the air with no load on it. I would suggest pulling the bearings and inspecting each and the race closely, if they are good, put a new seal, and repack, and cross one of your routine maintenance items off your list. Then pull the rear cover, look for metal in the oil, cleanliness, etc. Low level in the rear dif can do really bad things to axle bearings. Drop the center pin, pull the clips and remove the axles. Look for wear on the axle itself where the bearing rides, look for pitting on the bearing, etc.

Also, check for wear indications (shiney marks) on calipers, shoes, pads, drums, backing plates, dust shields, etc..

Personally, I do all this to every used vehicle I buy. Being an 11 year old vehicle, it probably needs it anyway, and if not, you won't be out much but some time, some gear oil, and a few seals. Cheap insurance, in my book.

You may also want to check your driveshaft really close for out of round, binding u-joint, etc. You would be surprised what a stuck u-joint can sound like.

I had one once that made a funny thump when I bought it, but only when I turned left.. It turned out to be a damn wheel weight of mammoth proportions hitting the tie rod end..

 

Did you check for a bent rim, or damaged tire when you had it up to check the bearings?


You may also check your flex plate where it bolts to the torque converter, a cracked flex plate can make some bad noises, too..

 

Thanks for the info BChance. I am going to try swapping out tires. If that is no good then I will go to checking the fluild in the diff. and asking for more info on how to remove the axles etc as you stated.
Thanks

 

How do I do that. Do I have to drop the tranny?

 

You should have an inspection plate. If I remember right (and I may not be) The most you will have to pull is the starter and a couple 1/4" bolts and the plate should come off and give you a decent view of the plate and the bolts holding the the torque converter.

Try the tires first though if you can feel the feel the truck bouncing/shaking much when you drive it. The flex plate being damaged will usually be more subtle and feel more like a vibration than an out of round tire or bent rim.

 

Thanks, I'll work on it and post back.

 

Does the noise go away if you hit the brakes? I had a similar noise recently, it turned out to be that the antirattle clips on the front brakes were worn out and the brake pads were moving around making that noise. I replaced my front brakes because they were worn out and put in new antirattle clips and the noise is gone.

 

No, I tried hitting the brakes hard, soft etc.. didn't notice any change but I will recheck that tonight. Thanks for the reminder. Can't hurt to double check. It's not really a grinding either I guess. It's more like if I had eggs for wheels.. At least that is the way it seems.

 

If you have a two piece shaft do not forget to check the center carrier bearing.

 

I do have one. I thought about that. However, how would I know if it was bad, and if I have this thumping continuously even coasting in nuetral could it still be that?