Thumping noise - 1993 80 Series (1 Viewer)

[Quicksand80]

Hey Cruiser heads! I've been experiencing a thumping noise coming from my 1993 80 series LC the last 8ish months. I can only really hear it between while driving between 20-50mph. I've replaced a ton of parts including bushings, bearings, flanges, and ujoints at both the front and rear end of the vehicle. It is driving me absolutely nuts trying to chase down the source of this noise.

I suspect it is related to my front axel for the following reasons:
1. A ton of metal shavings found in the front diff drain plug.
2. Seems like there is excessive play in the front driveshaft flange. I tightened the nut a bit more last night since I could move the flange side to side and in and out a bit.
3. The driver side knuckle is starting to seep fluid.
4. I can hear the noise more clearly sitting in the front than in the back.

The thumping noise started after a wheeling trip that involved some light rock crawling and a couple of water crossings.

Any and all help is appreciated as I would love to narrow this down a bit more before having to spend more money.

Here's a video I recorded earlier. You can hear it if you listen closely. I just placed my phone down on the driver side floor board.

 

[AgentOrange]

Hey Cruiser heads! I've been experiencing a thumping noise coming from my 1993 80 series LC the last 8ish months. I can only really hear it between while driving between 20-50mph. I've replaced a ton of parts including bushings, bearings, flanges, and ujoints at both the front and rear end of the vehicle. It is driving me absolutely nuts trying to chase down the source of this noise.

I suspect it is related to my front axel for the following reasons:
1. A ton of metal shavings found in the front diff drain plug.
2. Seems like there is excessive play in the front driveshaft flange. I tightened the nut a bit more last night since I could move the flange side to side and in and out a bit.
3. The driver side knuckle is starting to seep fluid.
4. I can hear the noise more clearly sitting in the front than in the back.

The thumping noise started after a wheeling trip that involved some light rock crawling and a couple of water crossings.

Any and all help is appreciated as I would love to narrow this down a bit more before having to spend more money.

Here's a video I recorded earlier. You can hear it if you listen closely. I just placed my phone down on the driver side floor board.

I'd start with what we know is probably bad. Metal in the drain plug and the pinion flange being so loose means at least the pinion bearings are toast, possibly more inside the diff. Tightening the pinion nut changed the pinion depth as well and it going to accelerate wear on those bearings even further. If there is more damage inside that front diff, all kinds of noises can result

 

[family80]

Sounds like it’s time to freshen up the front diff.

 

[LandLocked93]

Continue with your base lining. lol
Hit the knuckles and re-eval.
It sounds very much like a bearing noise. Could be the pinion, but also could be diff fluid in the DS knuckle that's thinned out the moly. Or worse, moved on out to the spindle/hub bearings.
Think I got my rebuild kit from @cruiseroutfit (cruiseroutfiters.com).
Guessing you've refreshed the diff fluid on account of the shavings you found. I'd hold up on the diff work until you get the knuckles sorted. (just my opinion)
And while you're in there, consider the knuckle stud kit from Wits'End.com. With Blue Locktite at least.

 

[love mud 99]

If the output shaft had/has play, you'll need to address that. You can do knuckles while you're in there.