tool

Coming home late last night, truck starts to make a bit of a thumping "Wump Wump Wump" sound. Similar to the sound of a blown tire....

At first just at low speeds, then on the highway as well. There is a noticeable vibration through the floor board with every WUMP.

at 70 MPH I'd say they happen every.................???? second maybe? or maybe 2 Wumps per second?? They are louder at low speeds crawling through parking lot etc.

Tried coasting at 60 MPH in neutral, still made the noise.

I had noticed a week or so ago there was some noise and vibration in 4x4..... Transfer case issue maybe?? Bad bearing? Hub?

Can anyone point me to what to check first?

Ideas?

duner

tires

tool

I'm positve this is something mechanical.

phox_mulder

Mine did that once.
Shifted in and out of 4x4 and it went away.

Never found out what it was, but I'd look to the ujoints on the front axle ends.


phox

tool

yeah, sounds like a REALLY bad u-joint but I just ahd them replaced.
like 5K ago

phox_mulder

Did you replace the driveshaft ujoints or the axle ujoints?
Or both?


phox

tool

Both axle u joints, some drive shaft.

wv smoker

I would check the wheel bearings also, just thinking of the frequency of the vibes at 70mph?? Usually a driveline bearing will have an almost continuous noise and vibration. I would check the tires for a broken belt or flat spot too.......Sure the front axle is disengaged?

tool

test drove it with a mechanic this aft. he thinks maybe front diff. I still think T-case.

tool

Dropped off at the shop, waiting to hear what they find.

After driving like 25 or 30 miles at 70 MPH with that much grinding going on I'd think if it was the diff it would be warm to the touch if not hot???

Was stone cold. I'm still betting on T-case..... But I'm not a 4wd expert by any means.