I agree with legoms013, use a fan clutch. I had an issue with an Autozone fan clutch and it was constantly engaged. I took the thing back out (it was made in china) and put a US made Hayden clutch in. It works flawlessly, and I've had it in for about a year. 
As far as an e-fan; if you do it right, they work great. But if you get a cheapy from Autozone and expect it to perform like the factory set up, you're kidding yourself. IMHO, you'll dump a lot more money into getting an E-fan to work properly than you will just to buy a decent brand of fan clutch. Just a thought because I gather from your rear differential comments that money is tight (as it is with most of us right now).