[MikeQBF]

As one of the resident transmission guys...

It might be doable. It's a totally self-contained mechanical system and there are no electronics to worry about - either switches or computer-controlled. The PTO (power take-off) is from the ring gear on the front differential, so you're not getting into transmission guts on either the A/T or M/T.

From the "junker", you're going have to recover: transfer gear assy, driveshaft, rear clutch/diff assy, and the rear axle with suspension bits. Without going out to the driveway to look, the only "challenge" I foresee is getting the new transfer gear hooked-up to the transmission without removing major engine support parts such as the subframe, for access. I'm fairly sure that you can get to the opening for the transfer gear without removing the transmission, which is a big job.

The junkyard approach is the only way to do this. It'll cost thousand$ to attempt this from the Honda parts counter.

 

[MikeQBF]

It doesn't happen that way. 4wd is from the factory or forget it (i.e., sell the 2wd and buy a 4wd).

 

[MikeQBF]

Please complete your profile since it's important for knowing our starting point for advice. If Rocket Dog hadn't bumped into figuring out that you had an SC from the color, you would have received misleading answers.

The answer in your case is "for all intents, no". You cannot realistically convert an SC to AWD without replacing a substantial portion - if not all - of the suspension, both front and back. Since the SC is lowered ('bout 1-1/2") versus the regular E, important clearances for the AWD mechanicals are compromised. This is the why the SC isn't offered in AWD in the first place.

 

[MikeQBF]

Well, then I stand corrected. My #1 concern with the SC was propeller shaft clearance from the transaxle. Not a lot of room there.

I do have to caution the OP that removing the transmission to install the transfer gear isn't trivial, and if it is an A/T then that's a whole 'nuther can o' worms. Easier, cheaper and far less time to just sell it and find another E with AWD.

 

[MikeQBF]

Doable. No ECU change; the whole AWD system is mechanical and has no control interfaces. Without the service manual in front of me I can't tell you if the A/T PTO is as easy as the M/T, where, like 'roller...' said, it's just a plate covering the PTO port.

In theory, you should be able to jack up the 2WD, unbolt everything from the struts down, slide everything over from your 4WD, hook the driveshaft up to the PTO and you're done. In theory.

Only caution I can think of is not to drive it mid-project with the driveshaft disconnected. The AWD clutch hydraulic logic might not deal predictably with thinking it had an extended "rear wheels turning, front wheels stopped" condition. That's never a real-world condition.