I just changed transfer case fluid on my father's F-350 for the first time in 13 years. (over 230k LOL)
Removed fill plug first and fluid gushed out of the fill hole unexpectedly. Did not have catch pan ready, so made a mess.
I thought it was just over filled form the factory, but too much was coming out to be simple overfill. Almost 2 qt came out of the fill plug.

Did some google search and found many Ford trucks have failed transmission output shaft seal and transmission fluid leaks out to transfer case, causing transfer case to overfill. I am yet to check transmission fluid level, but considering how much came out of it that probably is the case.

Now, how bad of the problem this really is? Will overfilled transfer case cause some serious problem? 4x4 is rarely used (once or twice a year in winter) on this truck and from what I understand transfer case doesn't really do anything in 2WD other than just passing output from transmission through.

There are no fluid leaking outside and repairing the seal would be a too much of work for me.



Also changed rear differential fluid for the first time and I was surprised how clean the fluid was. There were thin layer of black sticky residue (sludge?) covering everything, but the fluid itself looked clean and no visible metal shavings.
I guess that is why Ford said it does not require change under normal condition.

 

IIRC the spec is close to 2qts, but its been a while

 

Too much fluid isn't going to harm anything mechanical, the concern would be the transmission running low on fluid. I'd also be a bit worried about increased pressure on the output shaft seal if the fluid starts foaming.

 

unless ford has changed the design of stuff that I'm not aware of there isnt a seal on output shaft of a 4x4 trans. There's a seal on the input of the tcase. I personally haven't seen one go bad. But that doesn't mean it doesn't happen.

It's not really all that hard to change either. 6 bolts hold it to the trans..

 

My 2000 F150 used to do this all the time, it always seamed to do it when the trans got really warm from pulling a trailer or something. I could always tell when my transfer case was overfilled because for some reason it would make a high pitched squealing noise. I just learned to check it every six months or so and drain out any excess. As said keep a eye on the trans fluid..

 

Yes. The spec is 2 qts, but defiantly way more than 2 qts came out.

I will check the ATF level. It should eventually even out. Right?

I believe there is seal on both output of transmission and input of transfer case. Is it easy to remove seals after dropping transfer case?
The thing is I live in a condo and there is no garage that I can work in. Will be working in parking lot (I really am not supposed to.. but.. )

 

Did you ever get it fixed? Have not noticed any noise or performance issue until now. So I'm leaning toward just fill transmission fluid back to the level and leave transfer case overfilled.
I just don't know if this will damage transfer case (or damage is already done?)

 

I don't think so. Remember there's air in the transfer case as well, and that has to go somewhere as it fills up with liquid to maintain equilibrium since it's not a pressurized component.

It would eventually start coming out the vent hose.

 

Haven't had any fluid leaking outside so far. I don't know how long this problem has been going, but must been leaking slowly. I did not see any vent on transfer case, but there should be one somewhere on top since it is a sealed compartment. Right?

Is transmission fluid level higher than top of the transfer case?

 

No the fluid level is not higher that the top of the tcase. If I remember right, when you pull the tcase off, you will only loose a few qts out of the trans(if your on level ground)

Also, if you check your levels every oil change, you could always drain the little extra out of the tcase by letting it run out of the fill hole. If you have been getting the pickup serviced somewhere, they should have been checking the level for you.

As for removing the seal, it's not hard at all. Just get a screwdriver or small chisel and pound it in there and pry the seal out. Don't forget a new gasket for between the tcase and trans either. I'm still going with my original statement about there only being a seal on the input of the tcase. Untell someone proves me wrong. Lol

 

Nope never fixed it just kept a closer eye on it and drained one and filled the other as needed..