So, I was reinstalling my rear driveshaft tonight and decided to pull the drain plug and check the level of the fluid. Fluid level seemed fine, but the amount of stuff on the drain plug was disturbing:






Sorry for the crappy photos. I couldn't get my stupid camera to focus for some reason. This seems excessive to me.

I dipped my finger in the oil and pulled some out and it had a nice brown color to it, didn't look milky or anything. My stomach is starting to hurt....

 

That looks pretty normal to me, how many miles on this truck?

 

It has 106,000 miles on it. PO said it probably has 50,000-60,000 miles on it since the last diff oil change.

 

Guess i should have looked at your sig, sorry about that.

I wouldn't worry about the metal on the plug, still looks normal to me but for peace of mind it's not a big deal to pull the cover to change the fluid and get a good look at the gears and carrier.

If you are still worried about the third member causing the issue it's a full floater so you could pull the drive shaft and the axels, bolt some plastic cool whip or tupperwear lids over the end of the hub and take it for a short roll to see if the noise is still there. I have never done this with one of these sterlings but I have limped a few big trucks home this way when they lost a diff. Every diff failure I have seen or had that wasn't catastrophic ( to much power on too little diff) was accompinied by HUGE heat. They oil always smelled like a burnt turd( I was in the army 10 years and have actually smelled a burnt turd) and the heat coming off the diff was very easy to detect after driving.

 

It wasn't in my sig until you asked the question.

I have felt the third member after driving around for some time, and it never felt hot to me, so I guess that is good news. Hopefully I will have some time this weekend to tear into the rear wheels and check the parking brake and calipers a little closer.

Thanks a ton for the input, guys. I am at a loss so far as to what this is, but hopefully I will figure it out soon with all of the help from the forum and some more investigating.

 

By chance have you checked the fluid in the transfer case, not saying that is what I think it is......just curious.

FYI: is is supposed to be Mercon IV or Mercon V not gear oil in the T case.

 

Have not checked it yet. The PO had a new trans put in at 60k, and said it has the following:

6.0 (bigger trans cooler)
Hd clutches
Hd converter
Valve shift kit
Stock pump

Anyway, under the truck is basically dry, and both the trans and tcase look shiny and new, so I wouldn't expect the tcase to be low. I will check it though to confirm it is the right fluid and by chance see if it is low.

 

Just throwing more stuff out there:

when you looked at the brakes where the spring tensioners that keep the shoe pressed against the caliper still there? They are a little wire with a spring loop in the middle that attach to the inboard and outboard pad to keep it tight to the caliper. I am just wondering since the OP upgraded the tranney maybe he put some ceramic pads on it and they could get noisy if lightly pressing against the rotor.

 

I forgot to post something else that I noticed. When I had the rear tires up in the air and had my wife "driving" the wheels, I told her to put the brakes on to stop the wheels. Well, she did, and the rear wheels barely slowed. I told her to push harder, and she did and they eventually stopped. How are these trucks balanced from front to rear brakes? Is this normal, or do I have a problem with the rear calipers?

The truck brakes great. It doesn't pull to the side, and with the front rotors and pads replaced, there is no shudder. No ABS light (rear abs only on this truck).

Also, a little more description on the sound: It dies out just a little before I roll to a stop.

I still haven't had time to dig back into the truck. Just time sitting here agonizing that I made a stupid decision in buying this truck. So, the thoughts just keep floating in my head.


Thanks again,

Devin

 

Now that's weird, you might be on to something there. Our trucks have a lot of rear brake bias. No doubt those tires should've stopped cold as soon as she hit the pedal.

I'm not up on the nuances of brakes other than normal service items. I don't know if that is something you can pressure test or something. I know some cars have independent hydraulic line sets for "corner tires" such that you would only lose one front and one rear if you lost a line, but again on these I'm just not sure.

Guessing you checked easy stuff like fluid, etc.

Faced with your symptoms, I'd rebleed everything first thing.

 

I just checked it. Level is good, doesn't smell like gear oil, but it is a very dark color, which doesn't make me feel too good. It almost looks black in color. I texted the original owner to see what type of lubricant he used, but he has quit getting back to me in the past couple of weeks. Makes me think he wasn't the straight shooter that I thought he was.

 

Kind of look like this?

 

Yes, kind of like that.

 

That came out of my TC with 80k on it never changed, after change "sound" issue I had resolved. Change the fluid. Mercon IV or V either is fine, need about 2 quarts.

 

I tore into the truck some today. I took off the rear calipers and rotors. It wasn't the parking brake causing the noise. I did find that the driver's side axle seal is leaking. Also, the parking brake shoes look pretty worn.

Anyway, after I removed all of that, I spun the driveshaft. It is still hard to tell, but it really sounds like a noise is coming from the transfer case. I will try the fluid change and see if that fixes it. But first, it is time for axle seals and new parking brake shoes. The rear calipers seemed to move fine once I got them off. I am also going to flush the brake system.