Hello,
While I was on vacation. My 01 LTD Montero started making a loud noise up front. The car has 50k miles. This happened as I was driving up & down from 2k-6k elevations. It was hot and the noise appeared only driving up the mountain, not going back down. When I slowed to pull over there was another sound right before I came to a complete stop, like the car was looking for a gear then it kinda felt like it engaged then the car jumped a little. I took it to the dealer in the area, and they could not find nothing out of line. The noise sounds like a clanky metal fan. The dealer said that what I might be hearing is the fan clutch enagaging and since it was hot and the car was going up & down the mountain roads, it was trying to cool the engine? I took it back up the road again & sure enough the noise reappeared, but not going down the road. As I slowed, the 2ndr sound was that of the gears not locked and as soon as it did lock then there was a slight jump right before stopping. I'm lost as to what I should do. Should I replace the fan clutch & does it make a loud clanky noise when it does engage? I need help! Also, on the way home my engine light came on and the temp gauge went beyond the H. I changed both temp sensors on top of the engine and it still states Hot. I used a thermal gun to check the eng temp and it was no where near hot as the gauge was showing. Is there another sensor I might have missing or do I have to replace the white module board in the inst cluster.
All help will be greatly appreciated.

UPDATE: It appears the noise is back even on reg level surface streets. It's come on twice several weeks apart. Any ideas?

 

Replace the fan clutch. Sounds like it has gone bad and they are easy to change.

http://www.napaonline.com/Search/Det...+50050+2050008

59.oo at Napa

 

I actually found a thread on this site that talks about a grinding sound then a clunk. Looks like it might be one of soleniods that control the 4WD so I do not think it is the fan clutch afterall.