Loud constant noise when 4x4 is engaged

Hey Guys,
I would appreciate any help here. I have a 1998 Dodge Ram 1500 SLT (98,000 miles) and haven't had any major problems with the truck except for maintenance like brakes, etc. However, today I needed to engage the 4x4 and the truck didn't have any problems doing so. After I engaged the 4x4 the truck sounded like it was making a loud constant noise and the faster I drove the louder it got. I new that it didn't sound right so I disengaged the 4x4 and noticed something smelt burning. I suspected something wrong with the transfer case as I noticed some grease that has leaked out onto the outside. I did check the transfer case lubricant and added some but it didn't need much. Does anyone have any ideas as to what might be causing the problem? and what might need to be fixed? maybe any ideas to the cost of parts?

Thanks,
Jon

What type of noise? I had that problem at about that mileage also, it ended up being a front wheel bearing. It was fine until I engaged 4x4 then it would squeel or hum and get hot due to the torque on it. You could check them by jacking it up and checking for play. I'm not too familiar with the transfer case inside, but it's possable you have a bad bearing there also.

tony36,
Thanks for your input. It gives me an idea as to where to start to look. I don't think its the transfer case because I rarely use the 4x4, but I certainly won't rule it out. I will start with looking at the front wheel bearings as a possibility.

Hey Guys,
I was looking into checking the front wheel bearings as to what might cause my truck to squeal when I engage the 4x4. Is it possible to replace these myself or do I need to take it to a garage? My manual for the truck says special tools are needed, but I'm not sure what they might be. I would like to do the work myself to save on the labor. Please give me some ideas as to what might be involved.
Thanks,
Jon

I do mine myself, but they can be a real bear. No special tools required except a large socket for the spindle nut and the large hex head to remove the calippers. The hard part is breaking big nut loose and then the triangle shaped bearing casing loose. The last time I did mine I bent a 5ft solid breaker bar and had to end up heating it to get the nut broke loose. I have a 99 and the bearing and seal cost me almost $300, and I did it myself. It can be done, if you do it just take your time and think it through and you will do ok. Try not to bend the tin plate too much behind the bearing casing.