'80 -'86 full size bronco will have a 208 with a fixed rear yoke. '80 -'83 or so F150 will have fixed yoke 208 as well. '83-'86 F150 will have a slip yoke 208 which sucks because its alot longer and the fluid will dump out when you pull the rear driveshaft. Any 31 spline 6 bolt tcase will bolt to a np435.
My donor 86 bronco had a bw1345 which is HUGE! It has a fixed yokes (strap style for the front and rear). I want to get a 205 as long as it fits an AOD.
the 1345 was a 3/4 ton and 1 ton case, it shouldnt be under a bronco unless it was swapped in. Are you sure its not a 1356? That was a border year so it could have gotten one. A 205 will bolt right in place of it but your driveshafts might not be long enough. You will lose a ton of low range though, the 1345 is the best stock range you can get.