Diff clunk

2004 base model 2wd v6 stick shift tundra
Apparently the diff has been rebuilt before, it's covered in jb weld as well to stop a leak, but it's leaking again
I pulled off the fill plug and it was really loose but even tightened(not torqued to spec) it's still leaking
I put a quart of 75w90 synthetic walmart gear oil in it and now there's a clunk whenever I hit a bad bump or step on the gas in first, second, and third gear.
The truck needs a throw out bearing but the sound isn't coming from the transmission it sounds like it's coming from the diff.
Could my diff need another rebuild? It's probably been less than a year since the rebuild and it's doing this.
Also could it not having enough oil be doing this? I'm so broke right now I can't afford even a junkyard diff so I'm not sure what to do, please help Google sucks for this
I also went under my truck and there's no driveshaft play at all and I kicked at the suspension parts and it's not the suspension.

 

Whoever setup your differential prolly didn't do it correctly. The carrier and pinion have shims that are used to adjust lash and pinion depth. Change the oil and seal it as best you can. Be gentle - now is not the time to dump the clutch or practice burnouts. When your financial situation improves, consider a junkyard rearend in better condition than yours.

 

Yeah I'm gonna try to change a seal and see if it does anything. I actually moved some stuff around in the cab and the clunk went away so it wasn't even the diff in the first place I was just being stupid.
I talked to a few buddies who know what they're talking about and they said maybe when I get my money up I could get a junkyard diff and swap my new, good diff gears into it. Not sure if that's something done often on tundras or not, nor do I know how difficult it would be as I have essentially no mechanic experience but I do feel I know more than average so I might just attempt it

 

If the rear cover is leaking and covered in JB weld you'll need a whole replacement axle housing or someone with good welding skills to weld a new cover on it.

 

Upside: 2WD. So rear gearing is not a huge concern. Any access cab or reg cab rear axle assembly will technically fit your truck width-wise.

I can’t remember if the transmission crossmember crack was a problem for manuals or not. If caused clunking but usually during stop/go.

If it were me, I’d find a solid donor axle assembly at the JY via www.car-part.com and swap it in.

 

Yeah I'll look at that site I just opened up the drain plug and a literal slurry of glitter came out