It seems some people over fill the transfer case with oil. Is that the only one of the five fluids that can be over filled without harm? I know engine oil and transmisson are not to be over filled.

Thamks

What year truck do you have ? As a general rule you should not overfill any fluids.
There was some discussion about using motor oil in the TC and filling through the speed sensor on certain model years due to pump rub issues.

Thanks,

It is an 03' - guess I am thinking about the axles.

In general, I never advise to overfill or underfill, but it's a question of %.

Example: my wife's minivan calls for 4.2 quarts to top off. I put in 4 quarts and call it a day. I'm not opening up a quart for .2 in volume, especially when it won't even get to the lower end of the "range" in 5k miles for my next OCI. 5% volume represented.

Example: I overfill my Goldwing, which calls for 3.9 quarts. I put in 4 qrts and be done with it. Cannot even hardly tell on the dip stick. 2.5% volume change.

But the T-case is different. It calls for an even 2 quarts. To put in 3 quarts, as suggested by some, is a 50% overfill! That's a lot! I don't know that it will directly hurt anything, but there is potential that the chain could aerate the fluid more than necessary, or acceptable.

Overfilling the t-case is a suggestion made by one man, and it was his reaction to his perception of what happend to the fluid (I know - I personally spoke with him on the phone during my research). I don't subscribe to his logic, although no harm seems to come of it. The reality is that the reason fluid levels get too low is because people didn't check the fluid level. Ironically, people are anal-retentive about engine and tranny oil, but seem to neglect the xfer and diffs (probably because they are not nearly as easy to service). Weinberg essentially blamed the fluid for a lack of preventative maintenance; how is that the lube oil's fault?

Would you put in 50% more engine oil, just to feel "safe"? I would not. I do not over or under fill more than 10% of the total volume. Too many unknowns when you get grossly out of range.

Rather, I'd use a synthetic in the t-case to resiste the heat evaporation, giving longer fluid life and less "boil off". And I'd still check my fluid level in the xfer case every 25k mile or so.

As usual, great information dnewton3. I just found this thread during a search about my transfer case and you answered my question without
typing a (another) keystroke :) !