At whit's end... need urgent help!!!

[markdisco]

I wanted to change the gear oil because I hear a whine that gets louder as the truck moves faster... It is final-drive related because when the tranny shifts, it gets louder and louder even though engine RPM's drop. When I let go of the gas it stops for a moment until there is pressure on the drivetrain again and then the sound comes back.

So yesterday I decided to finally replace my gear oil in the transfer case and diffs. I started with the front diff and for good practice, I always remove the fill plug first to be sure that it comes out! The moment I took out the fill plug, greyish-brown oil started POURING out... The diff is supposed to hold only 1.6 ltres of fluid? There was easily double... I have never seen that much gunk come out of a diff. I have had the truck for a year now and never changed it, but I can bet anything that was the original fluid in there mixed with a whole bunch of water! The rear was a little better: the fluid was pink (?!?!) but there wasn't as much... Still over the fill plug but not nearly as full as the front one. I refilled them both with 75/90 synthetic Castrol. I tried changing the tarsnfer case fluid as well but I couldn't locate the fill plug! Where is it???

The whine is still there, which leads me to believe that my diff's bearings are beyond repair, or maybe it's my transfer case... But could a used driveshaft cause the whining as well? Hopefully I will get to changing the x-case oil soon and see if that helps. In another 1000 miles or so I am going to flush the diff oils and change them again to get as much of that gunk out. Maybe this time I'll just use regular dino oil because I am planning on doing another flush after and synthetic can get a little expensive!

What can this whining be??? I already changed a wheel bearing because it was diagnosed by my ex-mechanic as being the culprit ($500 later and the noise is STILL there!)

Any help is greatly appreciated!

 

[p m]

The t-case fill plug is on the rear of the t-case, driver's side, somewhat behind the parking brake drum. You need some slim 1/2" ratchet to get it out.

There's still a chance it's a t-case whine. Mine whined since I bought the truck 9 years ago.

 

[rmuller]

Fill plug is hiding behind the emergency brake cable... uses a 1/2" drive ... if you have a wobble extension it makes life a lot easier. Just use regular 75w90 dino and change it regularly.. You could also try some Lucas Oil Stabilizer to get rid of the whine... use 1 bottle of that, and 1 bottle of 75w90 in the transfer case..

 

[pdogg]

those gear driven t-cases whine as a rule... I used syn mobil 1, and it helped the whine a lot.

 

[AfiRover]

sounds like water in the diff and that means ? to your bearings
check your seals they could be leaking or its comming in through the breather just my $0.02

 

[markdisco]

You were right about the breather part... The breather hose was cut just above the axle. I replaced that yesterday as well. Do you guys think that a worn front driveshaft can make this noise? It has gotten louder over the past year, which is what worries me...

BTW, thank you all for your replies!

 

[rmuller]

take off the driveshaft, and grab the flanges (both transfer case and diff sides) and shake it around and see if it feels like a busted baring..

 

[BackInA88]

I don't see what year Disco you have?
But if you can lock your CDL, you can remove one drive shaft at a time and drive it to see if you can narrow it down.


Steve

 

[markdisco]

Its a 2000. My cdl is already locked right now because of all the snow and ice. I will try removing the front driveshaft this weekend to see if the noise goes away

 

[gmookher]

mines whines, it feels normal

 

[barefoot]

the whinning you describe sounds like bad pinion bearings. they whine with load on the diffs then quit when you let off the gas. with that much crappy oil in there, i could easilly see why. the other possibility is worn ring and pinion gears and the only way to check is to take it apart and look at the wear patterns (maybe post a close up pic here with some of that blus grease shit on them). there are others on here (mark) that could help you identify this.

transfer cased do whine on these things but if it has gotten worse over the last year i would put money on worn diff parts due to gritty milky oil. you just need to decide if it is annoying enough to spend the $$$ and time to fix it. new ring and pinions are expensive....bearings not so much.

there was a guy on here recently who had a similar noise that turned out to be u-joints. so, it might be a good idea to rule that out first by either smarts or plain ole parts changing.

enjoy!

 

[BJ64]

sounds like water in the diff and that means ? to your bearings
check your seals they could be leaking or its comming in through the breather just my $0.02

I agree.

 

[markdisco]

If it was in fact a worn pinion brearing, can that cause a catastrophic failure of my diff? Will parts sieze up and explode while driving?

Thanks for all the replies!

 

[DiscoChiefJJ]

I just had a similar whine, up and down in pitch with the speed of truck, coming from under the cabin, with a whiney/grindy sound as I let off on the accelerator at speed. My shop checked transfer case fluid and found metal in the TCase fluid with apparently worn bearings there. I will probably be changing my TCase out soon with a used part unless someone smarter than me on these trucks thinks you can keep on driving them safely with worn TCase bearings.

Maybe you have the same issue; I hope this helps.