hodgepodge79

Is it common that the gear-oil would pass from the M/T into the transfercase?
(I've searched around, and only saw examples of A/T fluid getting into the engine or cooling system)

Yesterday I noticed the transfercase soaked in gear-oil. It looked like it originated from the top, maybe where a breather is?
I pulled the fill plug, and about 1 quart of oil gushed out before subsiding. So, I pulled the Manual Transmission fill plug, and nothing. I put my finger in and reaching as far down as I could feel, nothing. I then drained about 2 quarts out of the transmission and 2.5 more from the transfercase.

Has anyone experienced this?

MudHippy

There's a seal at the output shaft of the transmission and one at the input shaft of the transfer case. They connect inside a small chamber. If the transmission seal went first, the oil, after filling the chamber, would build pressure in that compartment. If the vent(s) was plugged, maybe if not even. Causing the oil to be forced into the transfer case, through the seal at the input shaft. My best geuss. Both seals could be spent, also.

hodgepodge79

That seemed like a very probable diagnosis. Have you personally seen it on a Toyota?
BTW, do both the transmission and transfercase have breathers (like the frt/rr diffs)?

MudHippy

Yes, I had the experience personaly. Long story short, my t-case input shaft seal ruptured. When I seperated the t-case from the tranny, I had a pleasent suprise. I know both have breathers, I have a suspicion that chamber may have one also.

hodgepodge79

After more searching, here is some stuff I came across,...but still doesn't answer anything definitively.

https://www.yotatech.com/forums/show...ght=input+seal

https://www.yotatech.com/forums/show...ght=input+seal

Brendan

the seal on my cruiser between the tranny and t/c is blown and all the oil leaves the t/c. i mickey-moused it by removing the filler plugs and adding a threaded piece that i can connect the two using a piece of tubing. works fine for now until i get around to fixing it properly.

hodgepodge79

LOL. So the T-case and Tranny are freely exchanging fluid via this tube? That's a great idea! Where did you get a threaded piece with barbed ends or whatever?

MudHippy

How did you figure out what he meant there? That is dang clever. On both your accounts!

Brendan

i took the filler plug into a hydraulics supply shop and told them what i was intending to do. they came back with a couple of pieces and i was off to the races.

http://www.man-a-fre.com/parts_acces...ansfercase.htm

hodgepodge79

Can you go into any greater detail about this repair? Did you put the vehicle on a lift? Did you drop the transmission? or just remove the driveshafts and pull the t-case?
Where there any special tools to remove and install the seals?
Looks like I can get the seals way cheaper than some hose fittings, so I'll be doing this soon. I would appreciate as much detail as you can give!
Thanks.

MudHippy

No special tools needed, 30mm socket for t-case out-put shaft seals fr/rr, if they need to go, not used for the t-case rear input shaft seal. All the seals install with hammer and wood block, jerk the used one(s) out any ol' way ya please (prybar). Uninstalling the transfer case just involves, first, removing the speedo cable, unplugging the 4WD indicator switch at the t-case, and then disconnect the driveshafts. After, unscrew and take off the t-case shifter knob, then unbolt the t-case from the tranny, lastly unbolt the t-case crossmember, from the FRAME, not just from t-case. Or, you should do BOTH, and remove the crossmember seperately, without the t-case attached, if you really feel the need, doesn't matter. Then remove the t-case. Keep in mind it's gonna be heavy, I never weighed mine, but I'm geussin' well over 100lbs. You'll need to apply some force in splitting the units (tranny/t-case) apart, it's best to have a way to support the t-case and slide it to the rear while still supported. This helps protect the transmission rear (out-put shaft) seal. That's dat. Have fun. Oh, just RTV when reassemble, maybe some anti-seize for the t-case to tranny bolts. Also, no lift, should jack and stand it, but I didn't need to b/c 2" susp.+3" BL, a true advantage for either.

hodgepodge79

OK,...I just got done replacing the transmission rear (output shaft) seal on my w56 tranny (see lower-left corner of pic). It all went ok.
I had a hard time getting the speedometer cable out, the dust shield was trashed and there was a ton of crap baked on in there. Nothing a little LiquidWrench couldn't handle. After the transfercase was out, I could easily see that the tranny rear seal was trashed.
There are two pencil sized holes on the front of the transfercase that allows gear oil to spill over into this cavity and lube the outside of the bearings. Well, with the seal missing most of its lip, the tranny fluid was spilling into this cavity and filling up (overfilling) the t-case.
The hardest part was re-assembly,...getting the splined shaft of the t-case lined up with the splined collet of the tranny and mating them without damaging the new seal. Oh, and I forgot to lube up the seal opon re-assembly,...DOH!
I'll know tomorrow if I have been successful or not.

MudHippy

Cool, sounds like it went alright. I wouldn't worry too much about not lubing the seal, I've rarely remembered to do so. It hasn't caused any trouble for me. Sometimes a fresh seal will leak a tad, before it flattens that peaked edge through a little usage.