Diff decisions....
 

Rear pinion is leaking, crazy rumble/vibrations at high speeds (80km/hr+)......

i am bringing the truck in to the shop tonight after jams. Most likely i will need a diff rebuild. truck has 321K, i personally put on 21k of that. running 31's. it is a DD for now.... i started wheeling last year and was pretty rough on the stock driveline. while its apart at the shop do i get them to install a locker? if they are rebuilding the diff should i get new gears too?
i was just thinking something like the spartan from marlin would be good. i dont plan on moving up to +33's until i do a SAS.

time to spend some cash...fishing/wheeling trip planned in 15 days so i have to bring it to a shop.

It all comes down to how much money you want to spend and IF you actually need one. It is a good time to do it if they have everything apart and you will save money as opposed to having them take it apart AGAIN down the road to put a locker in.

Or if you have a bit of time and are in a crunch for cash there are plenty of diffs to be found on craigslist and local junk yards and you can swap a used one in your driveway. The beauty of the 3rd member. I'm sure you could pull that off in 15 days if you wanted.

Or it could just need a rear pinion seal and bearing. Again, it just comes down to $$$.

found a local used 3rd member with a locker. gotta remove it myself but heck its worth it.
i have been experiencing a vibration at high speeds since i got the truck @ 300K. i wonder if a diff bearing could last 21K with vibrations. if not then my vibes are obv coming from somewhere else.

You also said you have been wheeling it. At 300k+ miles it has got alot of wear no matter how the previous owner used it. Wheeling it may have just exposed a potential problem waiting to happen.

Good score on the 3rd member. Replace the axle seals while you are at it.

seals are allready done with the bearings over the winter. Dam those Aisins last forever :-)
I did change diff fluid when i did my bearings and seals..thick metal goop was all that came out....another indication my 3rd member is tired.
Waiting on confirmation from the guy it has a locker. he has one with and one without. i said i wanted the locker even if he didnt wanna give it up :guitar:

I was also thinking and just realized. the guy who had the truck before me installed 3 inch blocks in the rear. That could be my persistent source of vibe if my drive angles are out and the vibes would wear my pinion bearing and seal no?

If you are doing a lunchbox locker you should be able to install it later. Just pull the diff, pop the center pin and remove the spider gears. Then pop it in. If it were me id go with a selectable locker. Im not to familiar with toyota diffs so the process could be off but seriously save your money and buy a selectable locker.