hill

So ive had a few threads about this awful whoomp whoomp sound coming from the rear of my truck...

https://www.yotatech.com/forums/f16/how-tell-if-tire-f-ed-up-58335/

Does anyone have any advice on wether to change out my rear U-Joints on either end of my driveshaft... or have my bearings looked at??

Cheers

SupraSport

Any vibrations?
Any loud clunking noises when engaging the tranny?
How is it on the freeway?
Does the rythm of the "whoomp"s increase with the speed of the vehicle?

hill

No vibrations noticed.
Ive always had a small noise when engaging the tranny into reverse..but nothing more then before.
Freeway handling is fine.
Rythm of the "whoomp - whoomp" doesnt seem to increase with the speed of the vehicle. The only time the noise isnt heard is under about 10mph.

Id love it if you had some suggestions Suprasport

PirateFins

Put the rear up on some jack stands and run it. Take a look at the driveshaft and u-joints to see if there is any vibrations. I had my wife put it in 4th and engage the tranny, while I was under there, I could see the u-joint at the transfer case jump around. With the truck turned off and up look at the u-joints (rotate the shaft) themselves for broken caps etc.. You also might be able to hear the noise and isolate where it is from while it is running. If you are 4wd (couldn't tell) You can drop the entire driveshaft, put in 4wd and drive around in FWD, if the noise is still there you just ruled out the u-joints and it is in the tranny, transfer, or rear axle assembly. Just be careful while under there and the driveline running. I think I have the same noise you are describing and it is comming from the rear 3rd. My bearing might be toast because I found water in my fluid, when I was changing it.
Hope that helps.

MTL_4runner

That sounds a bit scary.....be sure to have everything very well supported if you try that.

SupraSport

hmmmmm, a whoomp noise usually is a tire issue...but you have already swaped the tires and vehicle speed doesn't change the rythm of the noise...... I'm stumped.

Maybe I can help you eliminate possibilities:

Bad bearing is usually a constant growl or grinding the generally increase or decrease when take a sharp turn. Usually louder at faster speeds. Check by rotating tire in air and feel for roughness

A bad U-joint will "clunk" when engageing the tranny and will cause vibrations at high speeds.

A bulged tire will make a whoomp noise rythmatic with the speed of the vehicle.

hmmmm, strap on your running shoes and runn along your truck as a friend is driving it to see if you can pin point the location. Or mabey lie on the back hatch. Also look for anything that might be rubbing on the tires or drive shaft. If anything else comes to me I'll post it up. Good luck

SupraSport

Yep, try that too. Just be carefull and make sure to use good jackstands on the axle.

PirateFins

It sure is. Make sure you use good jack stands and have the front wheels blocked. Keep everything clear of moving parts, you are just looking not feeling.

mtnfreak

Assuming you're 4WD, pull the rear drive shaft. Drive towards your favorite repair shop. If the noise is gone, have the shaft balanced and the u-joints replaced. If it's still there, have the shop look at (in order of least costly estimates) the wheels, rear differential, transfer case and tranny.