Outer Limits 4x4 Board

I'm no expert on Auto transmissions, and have manage to avoid having doing much to do with them, But,

For those of you who don't know, I've got an 80 Series auto, with the A440F trans in it.
A few weeks ago I noticed a slight whine while in low range, didn't think much of it and figured it'd be the center diff in the transfer case.as it only seemed to do it while it was locked.

Then about 2 weeks ago, the shift patterns started to play games, And I knew something was up.
On Friday night during repeated trips up to Wheeny creek to recover a Broken Patrol that whine got progressively worse, to the point where it now sounds like I've got a honkin supercharger under the bonnet. :eek:
On the last trip out after finally fixing the patrol, I lost drive, it felt like I'd just slipped it into neutral. If I turned the engine off for a few minutes when I started again It'd shudder a bit and I'd get Drive back but it'd eventually start slipping again.
Managed to limp it home luckily but even when it's stone cold now it still shudders and slips and has the whine. :mad:
I'm thinking the pump has gone, and I'd appreciate thoughts from you guys as to as to my Diagnosis and whether I should get it rebuilt, or try and source another one.

Also, can I get away with using the A440 and split case transfer from a 60 series if I can get hold of one of those ?

A440F is electronic controled a440 is not so you cant swap them, the whining noise is more than likely the pump the cause would be that the filter is full of crap from the transmission, short term you could remove the pan and clean the filter but it sound like you have a major problem.