not quite trail worthy... YET!

[Theelax42]

I just bought a 98 Mercury Mountaineer.. everything works (ok, the antenna doesn't go down, but it'll be replaced with a stubby soon anyway), and it came with great off road tires.. but this thing doesn't have low range, just all wheel drive (and a limited slip?). is there a way to replace the transfer case with one allowing for All wheel drive AND a low range, like a 2004 Explorer XLT?

 

[MrQ]

Yuppers, you are looking for a 4406 manual t-case out of a F150 with a 5.0, 4.9, or 4.6. Front driveshaft and rear driveshaft are different lengths. I believe @MountaineerGreen had an excellent write up on the swap.

 

[Mbrooks420]

I just bought a 98 Mercury Mountaineer.. everything works (ok, the antenna doesn't go down, but it'll be replaced with a stubby soon anyway), and it came with great off road tires.. but this thing doesn't have low range, just all wheel drive (and a limited slip?). is there a way to replace the transfer case with one allowing for All wheel drive AND a low range, like a 2004 Explorer XLT?

Yes, but it’s a fair amount of work. If you want to keep an AWD (technically automatic 4wd) you’d need a torque on demand 4406. I think these were most common in Expeditions.