Cruiserdrew
On the way there
If the diff is original, my guess is your pinion preload is close to zero. It's normal from wear, but it will cause other problems and a leaking pinion seal eventually.
I'd say decide now. If you're doing an 80 axle FF swap in the end, do it now. If that's going to get pushed off to the infinite future, then a diff rebuild is reasonable.
Remember, you could get another differential, rebuild it, and then the full swap could be done in a day easy. And a rebuilt differential now, can still be used with an 80 series housing. My FJ60 is set up like that with a harrop and 80 FF housing it's been great.
Now if cash is really tight, then a front to rear swap will be your friend. Don't bother messing with the diff at all. Just pull the spacer and you that with the diff that's currently in the front axle. The minimal use that the front gets, usually means that's for all intents, it's still good and you can just run it and run it.
I'd say decide now. If you're doing an 80 axle FF swap in the end, do it now. If that's going to get pushed off to the infinite future, then a diff rebuild is reasonable.
Remember, you could get another differential, rebuild it, and then the full swap could be done in a day easy. And a rebuilt differential now, can still be used with an 80 series housing. My FJ60 is set up like that with a harrop and 80 FF housing it's been great.
Now if cash is really tight, then a front to rear swap will be your friend. Don't bother messing with the diff at all. Just pull the spacer and you that with the diff that's currently in the front axle. The minimal use that the front gets, usually means that's for all intents, it's still good and you can just run it and run it.