1998 Mercury Mountaineer's Transfer case:

In July of 2003 I decided to tear into my 1998 Mercury Mountaineer's Transfer case.  The truck would have a loud clunking or banging noise when I would accelerate from a stop.  The problem started gradually, but over time with towing my sleds the banging got more and more often.  It got to the point where just about 1/4 throttle from a stop resulted in the problem.  I checked the drive shafts and the u-joints.  I found that the front drive shaft was bad.  It has a non servicable CV joint on the end of the drive shaft which bolts up to the transfer case.  It was trashed.  I thought for sure this was the problem.  Cost about $220 from a dealership for the part and I easily replaced it myself.    Well, I took it for a test drive and the clanking continued.  This did fix a major vibration problem I had while accelerating and while crusing between 60+ I had a bad vibration which was also corrected with the new driveshaft.  But the violent clanking continued.  I decided to take it to a dealer since I no longer have my lift at home and they told me it was the transfer case.  They wanted $1750 to install a rebuild.  Knowing that they usually suck you dry and being familiar with pulling things apart and reassembling them (see my other pages below) I decided to dig into the transfer case myself.  Here are some pictures as well as schematics for the Borg-Warner 4404 (BW4404 for short).

BW4404 exploded view:
 

Here is the bearing portion of the rebuild kit I got from Drivetrain Specialties!  The kit also included all new seals.  These guys are great.  Their number is 1-800-216-1632.  The rebuild kit cost $120 and the chain cost $106.  Not bad.  $250 with shipping was all I needed.

  These are pictures of the rear section of the transfer case after I cleaned it up.  The arrow points to a spring clip which clips into a groove in the bearing which is pressed on the output shaft.  This keeps the bearing in place in the rear portion of the housing.  Took me a while to figure it out.

The third picture has an arrow which shows the part that is clamped in place with the spring clip.  That is a bitch to remove, but I assume the correct tool would help. 

  Here I am 1/2 way done reassembling the transfer case.  The original chain was completely loose.  I saw evidence of the chain rubbing on the inside of the transfer case.  I assume when it skipped a tooth.  All of the sprockets and gears looked good so I didn't bother replacing them.