No pressing matter, just curious what function, if any, the transfer case has aside from 4WD operation? (is it doing anything when I'm not using 4wd?)

I'm asking because I changed the fluid in mine today (99 sport 4WD) and found it was blacker than sin and only 380ml (approx. .8 pints) drained out. A fair amount of debris, but all small.
I've not used the 4wd, but plan to this winter as necessary. I have done 3 drain/refills for my "regular" transmission, and figured I'd do the same for the transfer case. However, if the transfer case otherwise gets no action in regular DD conditions, a drain/fill seems kind of pointless . . . opinions?
On the other hand, of course, if the Tcase IS doing something important when not operating 4wd, I guess I can start worrying about the state I found the fluid (loosely defined) in.

 

The TC, when not being used in 4WD applications, is essentially an in and out box, meaing the transmission inputs drive and that drive goes directly through the TC and out the back to the rear wheels.

There are many components inside the TC that are still functioning even though it's not being used in 4WD. It is essential that the TC be maintained properly, i.e., regular fluid changes, inorder for the internals to keep functioning with minimum wear (oil pump, bearings, et al)

Start worrying. If the fluid was black and there was nearly nothing in it, damage has been in progress. Re-change the fluid several times from this point forward to get all the crud out of the TC and there is no metal in the drain pan. Use the same fluid as you use in your transmission - no Jesus juice required. Reshedule TC fluid change when you do your transmission fluid drain & refill at your well baby visit preventive maintennce work.

 

Lowers the final drive ratio when engaged.

 

Fooey. But thanks still.
I was hoping it would be more of an academic question rather than a "start worrying now" question, but that's good to know. I've only had this thing since May, but I'm wishing I had done this earlier. Does the Tcase fluid "interact" with the "other" transmission fluid (as opposed to separately contained)? I'd like to do another drain/fill of the trans fluid as well before winter as it's still not exceptionally red, although there's markedly less debris in it anymore. And yes, I am officially a dex/merc "hoarder" and threw that in the TC today

 

It's self contained.

 

Self-contained fighting unit.
haha, I like it. Just hope I can save it.
Stay tuned...had to use effing KROIL, a pipe and mallet just to loosen 7 of my differential bolts in the front. 3 are getting an overnight Kroil bath and I shall pray that they submit tomorrow. Geesh.

 

So, you did get some Kroil. Good work.

I just got my shipment of two spray cans the other day.

Be careful not to beat stuck bolts loose, you may snap the heads off.. Use steady pressure on them. Those differential cover bolts were put on with wet RTV under the cover, so the bolts are set in RTV. A Propane torch can be your friend in this case...used in moderation of course.

 

Oh **********...when my buddy helped me with oil pan gasket and had to torch something, I almost passed out. No torches in my future, sorry. haha. I was half-tempted to try an extracting socket and just commit to replacing the bolts. Might have to with one of them...afraid I've helped it to start rounding a tad.
I'll see how it goes tomorrow. Given what I've discovered on this thing, I don't think aborting the project is smart. Plus, I can see what I guess was the (original?) paper-ish gasket poking out one side, and I can already smell the beginnings of stench so I'll plan on having a barf bag ready. Actually had to use the kroil to get my torx socket out of the Tcase drain plug (!) once it finally released.
Remind me why I'm really digging this crap!

 

Those internal wrenching plugs on the TC are worthless. Trash them next time you do a TC fluid change and get two hex head drain plugs from NAPA and use them. Part number is on the pic.



The original method of sealing the diff cover was/is using RTV gasket maker. If there is a paper gasket in there someone has been in the diff before. Based on what you have been saying, I don't think the previous owner [butcher] installed the paper gasket when he changed the diff fluid, someone else did. The same butcher that left the diff vent off.

When you get around to reinstalling the front diff cover you can use RTV gasket maker. I use Permatex "Gear Oil RTV Sealant". Works good. Bolt torque is 30 foot/lbs. The previous butcher probably over torqued those bolts.

 

2.2 pints is the t-case capacity. I'm not worried if there wasn't much material in the lube.

I'm glad to see you are doing this maintenance and getting familiar with your Jeep.

If more folks did this, we'd have less threads about catastrophic issues like "My transfer case just exploded!! Frickin Jeeps!!"

 

Thanks CCKen, I will pick up the bolts fo sho.
The differential is being a colossal PITA (updated my DQ of the day in my concurrent differential post haha...), but I plan on winning that pissing match. Eventually. Propane is getting more attractive every moment. BOOM!

Thanks Cruiser...I needed something new to dote on since my "real" spawn are getting too self-sufficient for my fussing 8) I am in quite the panic, though, at the thought of a winter without adequate garage space in which to (warmly) hide out and tinker.