I recently purchased a used Rubicon and it makes a disturbing sound at very low speed just as transmission is about to disengage. I found evidence that it may have been swamped but have since thoroughly cleaned radiator, oil cooler and changed the oil. My question is, is the noise I am hearing an indication of serious damage or is it normal? I'm new to this so my apologies if I am going against protocol. I am hoping someone with experience servicing these machines will be able to help. I'm attaching a video with audio to show what it is doing. For background the machine is basically in mint condition and only has 7xx miles. The machine is fully warmed up and in drive with D1 selected. Listen closely when you see speedometer read 4 mph. File is too big to upload so I will add a link to the video on YouTube. Thanks.