Well, I'm getting ready to go to Moab this weekend and want to patch up any possible loose ends for mechanical failure and I figured I would finally ask you guys about this one. When in 4hi (cant seem to go fast neough in 4low) and going over say 30mph, during certain driving conditions, I will get a horrible grinding noise of a sorts. there are 2 instances in which this noise will occur. First, it seems to always occur over say 30mph. The noise comes whenever i'm holding in(or pushing in) the clutch and the transmission is in neutral(same noise occures if i'm crusing 30mph+ and slip the stick into the neutral position). So, lets call tranny in neutral the first instance of the noise since it appears to happen in any neutral instance. The next instance in which it occures is when i'm in gear and I let off the gas. It will make the grinding noise for a couple of seconds and then as soon as my car starts to coast(while still in gear mind you)it will go away(engine is still under load but not on the acceleration end).....so there is the noise for the few seconds betweeen drive and coast(not sure if the tranny goes into neutral between these 2 load bearing stages or not) So this may all come down to a 'no-load' state that it occures in and not neccesarily neutral. Now for the tcase history. This has occured ever since the sammy was bone stock, no gear, no lift,nothing. I put in a brand new set of calmini 6.5:1 gears and an entire transfercase re-build kit(syncros, everythign) when the gears were installed. The noise did not go away. Added my Trail tough YJ kit...still the noise. New transmission..still the noise. SOOOOO, i'm wondering if there is something in the tcase that you dont touch when rebuilding that could be causing this problme(like some internal clutch assembly that senses whether or not the case has a load on it), or if this normally happens when in 4-hi on a samurai? I would like to get it fixed if it is a legitimate problem before suffering breakage in the middle of nowhere.