thumping noise & feeling

[thejum57]

I just took off the old set of stock wheels, and put on some nice Jeep OEM used mags with 225/75/15 nice tires, used. Both sets are the same size. Don't know if this is a coincidence, but a couple of weeks with them on, there is a thumping noise, and feeling somewhere between the front end and cab? Hard to pin down noised while driving. This is a 2WD 5spd. 1986. Track bar is new, brakes should be good. I'm hoping it's not like a universal joint or problem with the drive shaft. It's not constant, but is there quite often, speed up and slows down with driving speed. I can't see any obstructions, the tires fit fine and there was no noise for at least 2 weeks.

Any suggestions?  

Thanks !!! 

[big66440]

When does it make the noise? turning? going over a bump? while braking?

[thejum57]

Accelerating, driving, and slowing down. On and off while cruising, more pronounced accelerating, and slowing down. Even when I take it out of gear while slowing down...tried that to see if it was a "power" issue. Turns, braking, or bumps make no difference.

[87MJTIM]

Old tires? How old? Were they sitting for a long time flat?  Tires could be bad from age and sitting flat.

 

Did you change the rims, also?  If so, is the new (old) rim damaged - warped or not round?

[Marine1Texas]

did you check the ujoints? if it is on down speed only, it could be ujoints with slop in them, and could be even a worn out bearing.

[Keyav8r]

Broken belt in tire. Still happens. Do you ever notice a little twitch in the rear or through the steering wheel during a slow roll.

You can spot a broken belt by jacking the truck up and spinning the wheel by hand (in the front) or letting the rears turn over at idle in 1st gear (may have to add a little parking brake drag to keep them from spinning too fast. You'll spot the break by a sudden shift in the tread pattern as the tire rolls. Also, watch for out of round tires. Broken belt can give you a rhythmic thumping noise at speed.

[HOrnbrod]

If it showed up two weeks after you replaced the tires/wheels, It's probably coincidence. Check your drivetrain mounts, especially the transmission mount pieces for loose mounting bolts and/or rotten rubber. 

[deziped1]

How about worn out/broken motor mount, or mounts. Engine flopping around side to side causes a lot of noise. Raise hood rev engine and see if engine is rolling to side.

[gogmorgo]

Seems silly I know, but have you checked your lug nuts? I... may have had this happen once.

[yxmj]

Seems silly I know, but have you checked your lug nuts? I... may have had this happen once.

 

Not silly at all.....and I have had it happen more than once......read any paper work that comes out of a reputable tire shop (i am looking at a cost-co bill now) and it will tell you to check your lug nuts after 100 kms and again after 500....

[gogmorgo]

I spent two weeks last fall trying to find the source of a pop-clunk. Couldn't figure it out. Then one day passing a car at 130, going back into my lane it felt like the back end wanted to go a different direction than the front. Pulled over and noticed I had around 40 degrees of camber on the back left wheel. Three lug nuts were gone, the two left were right next to each other, not even close to tight, and they'd hogged out the holes in the wheel. Thing is, the truck was parked for 16 months hadn't had wheels off for 18, and had been hauled 250k on a dolly, and driven almost 1000km in those two weeks. Popular theory is they were stolen but I really have no idea what happened, I always torque to spec and retorque after 50k or so. Pretty embarrassing to say the least.

[thejum57]

Yes, just like the owner's head, it was loose lug nuts! I've always heard that you should re torque aluminum or cast wheels after a short time. Duh! Three wheels were real snug, the drivers front wheel, 2 nuts were hand tight, and 2 were a tiny bit loose.  Really glad that was it.

Thanks for all the great suggestions!

 

[gogmorgo]

Thanks for asking before it, you know, fell off. Slightly loose lug nuts are a much easier fix than missing nuts, lugs, or worse... wheels.

[HOrnbrod]

Yes, just like the owner's head, it was loose lug nuts! I've always heard that you should re torque aluminum or cast wheels after a short time. Duh! Three wheels were real snug, the drivers front wheel, 2 nuts were hand tight, and 2 were a tiny bit loose.  Really glad that was it.

Thanks for all the great suggestions!

 

No worries, we've all done similar. Good you caught it before one of your wheels went south while driving north. That's happened to a lot of us too, including me.   :eek: