Rhythmic thumping

Hey guys

So i have a 3L nissan navara 2004 and recently it started making a rhythmic thumping sound at sort of 30+ kms/hr, it sounded almost identical to a train chugging along slowly.

I thought it could be my exhaust loose banging on the car but its definitely not. Now i have only been driving it slowly and so it doesn’t make the noise at low speeds but every now and then it feels as though the car drops down the front left, this isnt rhythmic like the sound, it happens mainly at very slow speeds and at random intervals.

I cant jack it up it has a lift and so i need a big jack to do that and so cannot check the tyres but i dont think it could be as the thumping doesn’t get faster or slower its always at same speed and same volume.

Also i havent noticed any change when turning, if anything it seems to only happen when going straight and i think it is worse when im slowing down to a stop.

Im going to check the lug nuts to see if theyre loose as this happened before but that was almost a year ago now and i feel if it was lug nuts it would have been worse by now.

Also the brake pedal feels ineffective at the top, then once it is pushed down a little way it engages so it could be my brakes but idk if that is a seperate problem.

Thankyou for taking time to listen and I hope someone can help me figure it out, i tried to provide as much info and if you have any questions ill be happy to answer.

It sure sound like a bad wheel bearing to me. When it gets really bad,the noise in the cabin will be unbearable.Do not delay this repair because you could eventually loose a wheel.You could post a sound clip so we could diagnose your problem better.

Have you looked the tire tread over for any abnormalities? Offhand, I might wild guess at a tire wear or balance problem.

As for the brakes, does this vehicle have drum brakes on the rear? If so, worn or out of adjustment rear brake shoes can cause a low or mushy pedal.

+1
However, if this is a case of separation inside the tire, it is possible that it would appear “normal” in a visual inspection.

I think that a tire-related problem is likely, but from afar it is not possible to figure out whether it is a balance problem, or tread wear related, or internal separation.

If you are certain of this it rules out anything related to the wheels turning.
Does it really not change with vehicle speed?
Or does it only happen in a very narrow speed range?

You say it’s lifted. It could be some loose suspension part wobbling.
You could bring the vehicle up to the speed it does it, then shift into neutral and let the engine idle.
If that changes the sound it could be related to engine (accessories) or the input side of the transmission.

However, if this is a case of separation inside the tire, it is possible that it would appear “normal” in a visual inspection.

Agree that it would look normal but in my experience the noise is at all speed’s for separation not just slow speed.

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Have the shop that installed the lift kit check it.

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