Rear Differential Fluid Change (3 Viewers)

[danimal24]

Thoughts on this? Changed rear fluid at about 35k miles and fluid is chocolate milk!! Previous change was a little milky, so did a quick fill and refill 35k ago (truck is at 285k now and a 2003 with the 4.10 open diff). I noticed the breather valve was shot (two way instead of one way) so I just replaced it. Assume I have lots of moisture in my rear end!!!

When I did the change last, I also flushed with brake cleaner from fill port and then blasted from drain port. When I drove off the next morning...heard a small crunch (assume some debris got caught in the gears). Bought new axle seals and differential gasket to pull 3rd member to see if I damaged anything...but never did it (time and seems like a real pain). Chasing some bearing noise either front or back of truck...noises play tricks on you when determining origin.

So...is my diff toast? Searching for a good used diff to swap in if I find issues during removal of noise is confirmed to be rear end.

Thanks!

 

[OEMGUY0720]

^I wouldn’t immediately say your R&P gears are toast, but for sure the fluid is. Was there any bigger materials at the bottom of the diff housing? If not I would say it’s still good. Any other weird sound the rear diff creates when you drive it? Usually the brown color indicates rust, rust means it has ingested a small amount water.

 

[GerLC100]

hhmm, to me it also looks like very low viscous and bubbly?!? or is it just me?!?

In case you're pulling axles, I'd likely also open up the diff at that time. And until then perhaps do 3-5 flushes after short drives to get the humidity/ water out?!?

 

[danimal24]

Thanks guys. Getting this off "whop...whoop...whop" noise and hard to tell where it is coming from. I thought it was my front wheel bearings...but those checked out (but replacing them next weekend cause they are pretty old and have to really torque them down to get 9-15 lbs on fish scale).

My boy thought he heard the noise coming from rear...so now focused on the rear!

Think the water intrusion was from the failed breather valve? I probably should drain and flush a few times.

I am looking for a good used 3rd member if can't figure this out and I end up pulling it to have a look...been having this "drag" feeling too...

 

[danimal24]

So I pulled the calipers and rotors and spun the wheels. Pretty loud grinding noises and creaking noises. Assume the diff fluid lubricates the rear wheel bearings? Maybe the water intrusion affected the bearings? Check out the videos and image of the ABS port (rust...). I have read about changing rear bearings...does not look like a fun task and need special tools.

(Update 1 hr later: just learned gear oil should NOT be where the ABS ring is. My seal is toast which means my bearings are probably toast as well)

 

[OEMGUY0720]

From your video I hear a lot of binding and excessive grinding, sounds like play in the bearings. As hard to accept as it seems, I would do a full rear differential rebuild with this. Differential housing seals replacement and bearings including full inspection of the third member.

 

[Foehammer]

Yikes that's nasty man.

 

[KeepGoing]

If anyone was wondering, I can confirm the rear hex drain plug with the long magnet works just fine. No issues with the magnet being too long.