Alarming Noise Coming From Under Jeep

[macleanflood]

I'd do as you started to do and try each driveshaft... it's a pain in the neck but it'll help isolate the issue.

-Mac

 

[JKP]

Have you checked the flex plate for cracks, loose bolts?

 

[Arthurius]

Have you checked the flex plate for cracks, loose bolts?

I have not, that's much more in-depth than the steps i have taken so far isn't it? Wouldn't that require me to back the trans off the engine?

 

[JKP]

I'm a MT guy, but I think there's a dust cover you can remove to get to it. Maybe some of the AT folks can confirm.

 

[Arthurius]

there's a dust cover you can remove to get to it

I'm seeing this inspection plate on some limited research on TJ flex plates, seems to be a somewhat common failure.

Interestingly, in maybe the last 500 or so miles I started to notice that the O/D OFF switch didn't seem to be having the affect I was used to. Not as much of an oomph factor. Doesn't that switch change the torque converter behavior, and isn't the flex plate part of that operation? Seems we are getting warmer...

 

[JKP]

The flex plate connects the engine to the torque converter.

O/D on/off just enables or disables the OD gear.

I would assume it has a lock up torque converter, so you may have something going on with the lock up portion of it.

 

[Arthurius]

O/D on/off just enables or disables the OD gear.

Okay, i will check under this inspection plate and report back! Thanks!

 

[Arthurius]

Another clue for the group,

I notice when starting the Jeep the sound is present immediately upon startup right before the first ignition, but goes away or is at least drowned out by the sound of the engine. I noticed this when i started it this weekend but i don't have enough starts to confirm it everytime. This noise on startup and return when shifting into gear in my mind may indicate a damaged flex plate.

Any holes in this logic? I'm taking my wrenches home at lunch to see how easily i can remove the inspection plate.

 

[macleanflood]

Check and make sure the starter bolts aren't loose...

-Mac

 

[BlueC]

What next? I removed my belly skid to start removing driveshafts but neck pain made me decide to wait for guidance. Should i try a flush of the transmission?

I doubt your driveshafts have anything to do with this, so I wouldn't bother pulling them. I would go about this by 1- finding a slope to let her roll down in neutral, engine off to see if the noise is there and/or 2- I'd go straight to servicing the trans, pull the pan and filter and see what you see. I think your noise will be in the trans, or possibly the engine.

 

[JKP]

Another clue for the group,

I notice when starting the Jeep the sound is present immediately upon startup right before the first ignition, but goes away or is at least drowned out by the sound of the engine. I noticed this when i started it this weekend but i don't have enough starts to confirm it everytime. This noise on startup and return when shifting into gear in my mind may indicate a damaged flex plate.

Any holes in this logic? I'm taking my wrenches home at lunch to see how easily i can remove the inspection plate.

Sounds good. You'll need to rotate the engine to get to all the bolts, inspect the entire flex plate.