Sorry if this is a repost, I searched for a while and didn't see anything on this.
I have a 2004 bone stock Liberty that hasn't seen much off road action. It is at 120,000kms and has been working great.
The other day I decided to do some light off road activities. I came to a rocky hill and decided to put it in 4x4 high. The light came on I stepped on the gas and the loudest thumping noise came from the front. Its a type of noise that you definitely don't want to re-create very often. I then switched it back to 4x2 and no noises.
When backed down to the bottom of the hill i put it back in 4x4 thinking that maybe it would be different on flat land. But no, the nasty thumping was back. It is definitely related to the drive train since standing still no noise and increases with speed.
Now let me explain the noise... its like a big gear set is slipping. it isn't a grind, squeak or howl. It is a thump that can be heard and felt. I am not too sure if it was from the front end or the transfer case.
I crawled under the truck and grabbed the front drive shaft, drivers and passenger CVs... all tight. The inner passenger side had a small amount of play maybe 1/32". Not too sure if that is the culprit. I am fearing the diff.
Any ideas on how/what i should check next?