I meant all the front end parts in my last post, you can use front end parts from a V6 Explorer (96-01) or Ranger (98-11) donor, the new front differential must have 3.73 gears (to match your existing rear axle).
The 4r70w trans MUST come from a 5.0L explorer awd to get the correct output shaft and tailhousing
This one has 95K miles and is under $500:
1996 1997 FORD EXPLORER MOUNTAINEER 5.0L 4R70W 4X4 AUTO TRANSMISSION TESTED 95K | eBay
This trans is from a 96-97 so to fit into your 98 it would need your current DTRS and the solenoids (and wiring pigtails from your 98 unit/new)
99 with 137K:
1999 FORD EXPLORER AUTOMATIC TRANSMISSION ASSEMBLY 137,000 MILES 5.0 4R70W | eBay
The 4406 t case and linkage comes from 4.2L v6 and 4.6L F150 trucks, 98-04 These trucks use the 4r70w transmission (Anything with the 5.4 or larger use the 4r100 and larger 4407 t case)
You want the front driveshaft from the same 4.6L truck
You want the rear driveshaft from a 97+ 4.6L expedition
The rest is covered in 4406 conversion threads
To go through this trouble for AWD you must really want AWD
MOST 5.0L explorers/Rangers we build use the 4406m case. It gives you more torque to the rear wheels, it lightens up the front steering and wear and tear on ball joints, wheel bearings and most importantly tires. The 5.0L AWD trucks are a little "doggy", when getting on the highway or trying to pass somebody, when the trans kicks down into 3 it leaves something to be desired. With the 4x4 conversion in 2wd this mod brings you "passing power" and better overall MPG (pays for itself in gas and mostly tires).
The true 4x4 50/50 2wd, 4hi, 4low 4406 in a Gen II explorer is awesome.
It turns your Explorer into a real truck
My 1988 Bronco II Eddie Bauer has over 300K miles on it. It has a retail value of about $300 LMAO
Over the last 20+ years I have easily put 30K into this truck, but I have also driven it daily the whole time.
30000 / 20 = 1500 a year. Cheap right? No payments, no interest, lots of cussing and learning. Parts and insurance are cheap, labor is expensive. So I am the labor. Sometimes I put $5000 into it in a month, then there are years where she just gets gas and oil (pretty much since 2005 when I went V8).
Well 4 engines and 6-7 transmissions later (learning curve/test mule/weekend warrior)
she now has 90K on the 280-290hp 5.0, about 5000 miles on the fresh 4r70w, 2500 miles on my current 94 explorer 1354m t case, 35" duratracs, 4.10 yukon gears, dual ARB lockers, custom long travel suspension, 4 wheel disc brakes, heated leather seats, Autometer gauges, etc etc etc Duff front and rear bumpers, custom front to back, interior, exterior...........As far as Bronco II's go this one is worth its weight.
I plan to keep it forever unless I get a wild hair and transfer all these parts to something else.
My point is, it's not always about "retail value"
Driving a Bronco daily for 20 years and having something completely custom on the cheap....any wife can see the logic in that