Help identifying drivetrain noise

[Bastian]

Hi,

Greetings from Ibiza, Spain! This is my first post on here and I hope you can help me.

My Jeep has over 300.000km and is mostly still going strong. Engine still has good compression pulls well.

However... Recently the drivetrain has developed a funny clunking noise. I think it’s on or near the transmission. I did replace the rubber transmission block/mount last summer.

Here is a video of the noise.

I hope someone can help me to identify it or point me in the right direction.

I don’t see anything obvious when I’m under the car with the engine running.

Bastian

 

[Goatman]

It seems rpm specific. Sound to me like a broken engine mount or something.
Were you moving in the video or just shifting gear with your foot on the brakes?
If you were moving that would open up a whole different set of possibilities.
So if you were moving then I'd be looking to Ujoints or perhaps the drive shaft making contact with something. I'm not an automatic transmission type, so bear that in mind. Have you checked all fluid levels to be sure they are full?
Check front serpentine belt for a loose pulley hitting something.
Each time I listen it sounds different to me. Something spinning hitting a plastic guard? Front axle Ujoints?

 

[Bastian]

Thank you Goatman! I really appreciate you helping me.

The previous videos is when the car is not moving and stationary. Just shifting gear with my foot on the brake.

Engine and transmission mounts are new. All fluids are ok also. Pullies are ok.

Here’s a video of me moving (slowly entering the garages). At 10mph the sound goes away.

Could be the front u-joints. Are those moving while stationary?

 

[Bastian]

I just checked. Neither the front nor the rear driveshafts are moving when the car is stationary and I’m shifting with my foot on the brake so I doubt it’s the U joints.

 

[B34C0N]

From the shifter it looks like a 32RH transmission is that correct?

If you put your transfer case in neutral does it go away?

 

[Bastian]

Thanks for all your help. Yes, it’s a 32RH. And no, it doesn’t go away in neutral.

 

[rasband]

Have you checked all the parts your belt hits up front? It seems like shifting may only change the RPMs a little, and consequently the sound. You could probably leave it in park and running and carefully look around where the belt spins. It could be as simple as a pulley. I've felt around the engine bay more than once to narrow down a location, along that train of thought - have you checked all your fluid levels? I had a similar sound once and found the oil was mostly dry and my head gasket was toast (though that was in a subaru).

 

[Bastian]

Pulleys are good. Noise seems to come from the gearbox or transfercase. Will re-check fluid levels tomorrow just in case.

In this video you can see what it sounds like under the car. It’s louder inside the car.

 

[Bastian]

I did check out the fluid levels. All good. I’ll check next week to see if the rubber gearbox damper is appropriately torqued.

If anyone has any other suggestions I’d appreciate it.

 

[mrblaine]

I'm putting my money on a cracked flex plate.

 

[liquidfluidity]

How about fan vs shroud?

 

[Bastian]

checked it and plate looks fine and bolts were tight.

My mechanic friend thinks it’s from inside the gearbox.

I'm putting my money on a cracked flex plate.

 

[Bastian]

sound comes from the gearbox area.

How about fan vs shroud?

 

[mrblaine]

checked it and plate looks fine and bolts were tight.

My mechanic friend thinks it’s from inside the gearbox.

You can't check where they crack unless you drop the transmission. They crack around the 6 bolts that hold the flex plate to the crank.

 

[deleted]

deleted