I NEED HELP! Is It Wheel Bearings or Front U-Joint/ CV Joint?

[gshep12]

I was underneath my 4WD Exploda last Friday and was checking how the Front drive shaft felt compared to the Rear drive shaft. There wasn't any movement up or down or back and forth on the Rear Drive shaft. On the Front Driveshaft I placed my hand approximately in the center and I was able to move the drive shaft slightly up and down and back and forth, I assume this might be play. Can someone tell me if the front should feel this way? Should it be rigid like the Rear Drive shaft, with no movement at all? Based on sympton does anyone feel this could be a bad U-joint/ CV joint on the front? Could a bad U-joint/ CV joint produce a rumble sound at highway speed?
In addition I read on the Alldata website that a rumble noise can be worn wheel bearings. I"m aware that the front wheel bearing are known to go prematurely. Can they be worn and not have play? When the Tech checked them using the 12 and 6 o’clock technique he said there’s no play. To date I've had one rear wheel bearing replaced, which made no noise. What can be causing this horrible rumble sound that increases in amplitude as my speed increases? It is not the notorious Whine or Hum that the Rear Differentals produce. I'm running Bridgestone Alenza's on the truck; supposedly they're all balanced. I was told they have a slight hop on all four, I don't feel a lot of bouncing especially at highway speed. Could a hop produce an extreme rumble at highway speed? I have less than 30k on tires rated to last up to 65K; there is still plenty tread above the wear indicator. Any info on this will be appreciated.

 

[firman]

i assume u had the x level and in neutral when checking rear driveshaft, if its in park u wont feel any play.

 

[jrford]

On the Front Driveshaft I placed my hand approximately in the center and I was able to move the drive shaft slightly up and down and back and forth, I assume this might be play.

that would be bad, any up/down side/side is not good, rotational is OK, changes in the length (slight front/back) is ok. Where does it move in the the rear CV joint, shaft coming out of the Xfr Case, or the Front by the Pinion bearing. . . .is the front diff dry? No leaks?

 

[gshep12]

that would be bad, any up/down side/side is not good, rotational is OK, changes in the length (slight front/back) is ok. Where does it move in the the rear CV joint, shaft coming out of the Xfr Case, or the Front by the Pinion bearing. . . .is the front diff dry? No leaks?

The front diff is full & dry, slight spill from when fluid was checked last week. I'd like to say it felt like there was play on the output of the front diff, u-joint I think. The portion closes to the transfer case (CV joint) I don't recall play being at that end of shaft. However my memory is a bit selective at the moment for obvious reasons. I know the CV joint is not repairable, the U-joint on the otherhand is I believe, let it be that. I found someone who I think I can trust; he has worked exclusively with drive train systems for years, he will road test and check vehicle hopefully by weeks end.

 

[kickitagain]

I"m aware that the front wheel bearing are known to go prematurely. Can they be worn and not have play? When the Tech checked them using the 12 and 6 o’clock technique he said there’s no play.

When my front wheel bearings wore out there was no detectable play when I raised the front end to check. There was a hum that later became more of a roar when the vehicle was slightly off dead center. It was quite only when driving on a straight flat section of highway. I may hold a record with 160K on original front bearings. The right rear bearing went out at 78K. It produced a loud grinding noise when it went. I changed the left rear bear around 125K.

 

[tony5308]

I have a 1997 awd with 209,000 miles all original. started making a clunking noise with vibration at low speed acceleration