Have replaced the transmission fluid + filter twice after repairing the oil cooler lines. topped up the transmission fluid very well according to spec.
Transmission drives very well, gears switch very smoothly. Generally transmission works perfectly, up shifts and down shifts are very good.

Only issue is a clicking noise that is noticed at low rpms. It comes from the bell housing. The noise vanishes when rpm rises but i think its there but not noticed due to driving noise from the environment.
the noise appears at all transmission states i.e. Neutral, in gear and at park

The clicking sound is at the highest level when the rpm decreases after a rapid increase in rpm.

Have recorded a video at this link where the sound is produced ----> https://photos.app.goo.gl/viAt71Aca52tpv889

Could it be the torque converter? or the flex plate? Torque converter does it job perfectly no signs of functional problems. it engages very well at all states.

What are your thoughts?

 

Did the noise appear right after your repair or was it already there?

My thought is that it sounds like an exhaust issue. It moves too fast to be in the torque converter as it’s surrounded by fluid and couldn’t respond that quickly. Maybe one of the nuts holding onto the front flange to cat pipe? Being a 97’, is the exhaust support bracket present at the rear of the transmission? With the engine off, use a rubber mallet to gently tap the exhaust all around the transmission.

 

Thanks for the quick reply!

The noise was there before the repairs (oil +filter changes, oil cooler pipe replacements)

The bracket of the cat that is mounted on the trans are tightened well so that shouldn't be.

Have knocked the exhaust all around many times but no clicking sound appears.. exhaust related noise was one of my original thoughts too.. but the noise feels that it comes straight from within the bell housing when I'm under the car in the workshop with the engine running.

 

What about the two brackets for the catalytic converters? If they are tight, maybe remove them all the way and tap the bottom of the cats to see if the honeycomb inside has come loose. I know those early XJ’s have those flex pipes that can break apart if that exhaust bracket was broken. I know you said that it was secured though. Can you get the car off the ground safe and secured enough to have someone in the car and you underneath it while they tapped the gas pedal to make the noise so you can see if you can pinpoint it more??

Check all the torque converter bolts to see if they are tight. There’s only 3 of them.

 

does it need more ATF? you might be hearing the trans pump?

 

Transmissions do not normally make that kind of noise unless the fluid is low.
Have you used a stethoscope to pinpoint the noise origination? Sound has
a way of seeming like it's coming from one place when it is actually originating
from somewhere else.