Dirty transfer case oil

So I changed my transfer case oil today and the old came out looking like a rusty red color and there was lots of grit on both drain and fill plugs like sand had gotten into it.
It's been about 50k miles since last oil change.
Is this normal?
I know I'm way past oil change interval here.

 

No, that doesn't sound normal. I'd drive it for a few days and change it again. If there is any foreign stuff in there, you'll want to flush it out.

 

Did you do the previous change? Did it stink like dirty gear oil or like ATF?

 

Is the T-case on these vented?

 

Have you driven through deep water? The previous owner may have.Where is this truck located? Could it have been salt water? I would run walmart type semi synthetic gear oil through it for a few drain and fill cycles over a few weeks and see what happens. Run it in four wheel drive on a loose surface to get everything moving. Sounds like the front and rear end may be in trouble too, check those.

 

My transfer case oil at 60k looked brand new and it had never been changed, but my front/rear diffs looked black and gross (rear was changed at 30k)

Matt

 

I've changed the trans and transfer case lube twice , the rear end twice and the front end once since new. The drain oils were all clean but the front end was the darkest of all of them. I'd say the front end needs more frequent attention than the manual would suggest. I'll do the front again in the spring, black oil (other than engine oil) bothers me. Lube changes are cheap insurance.

 

When I changed all 3 at 60k, rear and transfer case looked brand new. Front was extremely dark.

 

I've owned the truck since new and changed the tranfer case oil at 40k miles with mobile one 75w90 synthetic and now again at 90k.
I've never ran it through deep water. Only thing I can think of is if theres a breather on the tranfer case that would allow sand to get in.
Most of my offroad driving is in soft sand.

 

I plan on running this oil for a couple weeks and then I'll change it again. Think it would be alright to run an ounce or two of sea foam or something like that to help clean the transfer case for the next couple weeks?

 

Get or borrow a borescope to check in the innards before you put any cleaner in there. Cleaners can cause more harm than good; so best to use them as a last resort. I would rinse with cheap gear oil (Walmart brand comes to mind), then run some more cheap gear oil for only about 20 miles. Drain and evaluate; then decide if a cleaner is necessary. Hopefully no. For gear oil till the next drain, Walmart's synthetic blend is a good value, imo.

 

Mine was the same way on my first change at 60k. Weird how the front was the darkest on ours...

 

Agree with everyone on the page. Not normal to have it dirty. I changed mine with 50K miles and it was as clean as new.

 

If the grit is on the plugs, it's not sand, it's metal

 

It's not metal, not magnetic. It looks and feels like sand.
How is sand getting into my tranfer case?

 

Something must be loose,missing or have a hole in it above the oil level or it would be leaking oil right? Sand ,water and road grit is getting in somehow.

 

I'll have to really take a good look at it. I will say though with the new oil it seems to run alot smoother even in 2wd.

 

I think that question needs to be answered first. I'm not 100% sure either way if the t-case is vented. I suspect it is (just like the diffs) and that should be the ONLY way anything could get into the transfer case. The rusty color isn't likely to actually be rust. If any water got in there the oil would look like a milkshake. How do you use your truck? Have you sunk it into any deep mud holes since the last time you changed the fluid?

 

That’s a good idea. Even some cheap gear oil would work for a flush. Your gonna drain it any way before you put the good stuff in. You just need to get the sand out.

 

Does the transfer case have an input shaft from the transmission that maybe a seal could be leaking into?