I owned several early Broncos..never towed one though.
Jeep 4X4 flat tow (1977 Jeep uses same transfer case)
Transfer case uses a slinger oil ring on input shaft so transfer case needs to be in NEUTRAL so nothing is moving.
Auto transmission should be in PARK
Front Hubs should be IN so front drive shaft turns....output shaft can then sling oil
Like I said......never flat towed a Bronco but did tow a Jeep.
Might what to go to a Ford Bronco site and ask about flat towing.
Don't know if still up and running......http://classicbroncos.com/
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31