Overfilled transfer case, possibly a leaky output shaft seal?

[OverlandExpy]

I just pulled the fill plug out of my 4wd 04, and a TON of fluid came out. The drain plug is still in. Maybe the last person to fill it did so on an incline, but there was really a lot of fluid pouring out, I'm pretty much drenched right now since I was not expecting it to come out of the fill plug. I saw a comment somewhere that said a leaky shaft seal could be the culprit, and sure enough where the driveline leaves the transfer case and goes to the front diff, there is a lot of caked old oil around it. Pretty much black. There is a breather hose at the top of the transfer case, pointing towards the front of the truck, and it seemed to be leaking looking at the pattern of the oil, so I put a hose clamp on it, but was just wondering if anyone has had this problem before and if its worth replacing a seal. I know its not the easiest job when you have to start pulling the drivelines out.

Also while I'm here, are there any other zerk fittings on the entire truck other than the front lower ball joints?? I bought a whole tube of ford spec Moly grease and used two squirts so far lol

 

[OverlandExpy]

Just going through my old posts and saw this one, I never figured out what was going on, any ideas?

 

[OverlandExpy]

Also anyone know if the BW4416 transfer case is locked when in 4L/4H? Or have any technical documents for it? I've been going crazy trying to find any info about it online, and the service/shop manual doesn't have tons about how it works. I have the exploded view of it, but honestly no idea how to find out if its locked from just that.

 

[Tractmec]

The Transfer case locks direct in 4HI and 4low by the the transfer case shift motor turning a cam and and shifting a collar to connect the transmission out put shaft to the front drive sprocket(4HI direct drive) and to gear reduction Planetary gear set in 4 low after the Electric clutch(4HI only) has engaged and brought the front drive shaft up to the same RPM as the rear drive shaft and the front axle integrated wheel ends (IWE) have engaged(4HI only the vehicle must be stopped and in neutral with the brakes on to shift to 4Low). You should hear clunking noises come from the transfer case if you shift the transfer case to 4Hi or 4low while the vehicle is stopped!

In AWD(if this one has that option) the IWE's engage along with the electric clutch on initial selection and stay engaged and electric clutch will only then engage and drive the front axle when the difference in rpm between the front and rear output speed sensor data(Rear Drive overruns the front drive) reaches a certain percentage set in the PCM and 4WD control module! Then the electric clutch engages to bring the two drives back to the preset allowable difference(for cornering on hard surfaces while in AWD etc.) The Transfer case is not locked direct at any time while in AWD/A4WD!

As to your transfer case over fill question, check that your transmission fluid level is not going down or up as the seal between the transmission and transfer case(located on the transfer case in put shaft) can leak and transfer fluid between the two! Also make sure that the breathers on both transmission and transfer case are open(good idea to check these

on the differentials while you are under there too) are open! Also a leak at the front drive out put shaft would cause the transfer case level to go down not up but the over fill condition can cause cases to over heat and cause oil to leak out of seals and joints that would not leak under otherwise normal conditions!

As far as zerks go my 03 does not even have them on any ball joints or tie rod end or u joints! If yours has them there it is likely those ball joints have been replaced sometime in the vehicles life time with grease-able joints!

Hope that helps clears up your questions!

 

[OverlandExpy]

The Transfer case locks direct in 4HI and 4low by the the transfer case shift motor turning a cam and and shifting a collar to connect the transmission out put shaft to the front drive sprocket(4HI direct drive) and to gear reduction Planetary gear set in 4 low after the Electric clutch(4HI only) has engaged and brought the front drive shaft up to the same RPM as the rear drive shaft and the front axle integrated wheel ends (IWE) have engaged(4HI only the vehicle must be stopped and in neutral with the brakes on to shift to 4Low). You should hear clunking noises come from the transfer case if you shift the transfer case to 4Hi or 4low while the vehicle is stopped!

In AWD(if this one has that option) the IWE's engage along with the electric clutch on initial selection and stay engaged and electric clutch will only then engage and drive the front axle when the difference in rpm between the front and rear output speed sensor data(Rear Drive overruns the front drive) reaches a certain percentage set in the PCM and 4WD control module! Then the electric clutch engages to bring the two drives back to the preset allowable difference(for cornering on hard surfaces while in AWD etc.) The Transfer case is not locked direct at any time while in AWD/A4WD!

As to your transfer case over fill question, check that your transmission fluid level is not going down or up as the seal between the transmission and transfer case(located on the transfer case in put shaft) can leak and transfer fluid between the two! Also make sure that the breathers on both transmission and transfer case are open(good idea to check these


on the differentials while you are under there too) are open! Also a leak at the front drive out put shaft would cause the transfer case level to go down not up but the over fill condition can cause cases to over heat and cause oil to leak out of seals and joints that would not leak under otherwise normal conditions!

As far as zerks go my 03 does not even have them on any ball joints or tie rod end or u joints! If yours has them there it is likely those ball joints have been replaced sometime in the vehicles life time with grease-able joints!

Hope that helps clears up your questions!

Awesome man thank you for the very detailed reply! Mine does have the a4wd option but I pretty much only keep it in 2H. Stoked that it actually locks, I'm planning on putting Detroit lockers in my front and rear diffs... When I can afford it lol. Can't wait to have a triple locked offroad rig

I changed the transfer case fluid last year and have maybe driven it 200 or so miles since then since I mainly use this thing for my offroad adventures and I've been swamped with other projects and work lately. I'm going to check out if it's over filled again soon, I'm hoping it's right at the fill plug as it should be and it was just over filled from the last person who serviced it before I bought it.

Unfortunately none on my truck either. Would it be worthwhile to just slather the drive line joints with the moly grease I have? I was thinking of greasing everything when I drop my diffs out to put the lockers in. Gonna be a big job getting them out according to the service manual.. Gotta remove the LCA bolts and pretty much the whole rear end just to get the half shafts out. But I figured since I'm taking my whole drive line out I should grease it up good while I have the chance.

 

[whtbronco]

The transmission output shaft seal in the transfer case failed on my '04 as well which filled the transfer case. Simple replacement, but it took 2 of us to get the transfer case back in and as usual I gave up on the trans jack. Just bench pressed it.

Note worthy for me that was that I had trouble getting the seal out. I drove 2 screws into it, on opposing sides. Then with 2 vise-grips I just wiggled it out.

Very interesting that over filling the transfer case can cause it to overheat.
I found my transmission fluid low. My 4R70W has always liked to be filled about 1/3qt above the max on the dipstick. Otherwise it will not down shift in a hard right hand turn. So I knew it was low on my way home and found it was heading into my transfer case.