LB7 Transfer Case Serious leak from output shaft seal, Transfer Case fluid is full

[mojito5000]

Title says it all. Drove back from the airport the other day and when I went out to my truck this morning the passenger side had oil on it, looking at the undercarriage it's caked with oil. First worry was pump rub, but it looks like the oil is only coming from the seal, I washed down the rub area and it looks and feels solid. I got a new seal and installed it, when I went to fill the fluid, it was full. SO, now I think it's something from the transmission leaking in? It looks like the oil was pushed out by force. Trans is still good on oil, so luckily I didn't burn that up.

What am I looking at here? Was supposed to take the travel trailer and fam on vacation this weekend, now it looks like I'll be wrenching.

 

[Chevy1925]

If its overfilling, it means the tcase input seal is letting trans fluid in

 

[mojito5000]

So it's just a rebuild of the transfer case, not something on/in the transmission? I read about a seal on the transmission that would cause this too?

 

[Bdsankey]

So it's just a rebuild of the transfer case, not something on/in the transmission? I read about a seal on the transmission that would cause this too?

There is zero seal on a 4wd Allison that will cause this. The seal is on the input of the transfer case. You can change that seal and move on with life if you don't have any excessive play or wear.

Usually I see "TC" referenced as the torque converter so it's possible your searches may have pulled up front pump seal leaks.

 

[mojito5000]

There is zero seal on a 4wd Allison that will cause this. The seal is on the input of the transfer case. You can change that seal and move on with life if you don't have any excessive play or wear.

Usually I see "TC" referenced as the torque converter so it's possible your searches may have pulled up front pump seal leaks.

Fixed the title, I usually spend my days in the LB7 forum

That's good news. I don't feel any play in the chain on the output shaft of the transfer case. I'll remove it this weekend and see what I can find.

 

[mojito5000]

One thing I was thinking of last night, could there be something going on in the transmission, fluid pressure or flow that could cause this?

 

[Bdsankey]

One thing I was thinking of last night, could there be something going on in the transmission, fluid pressure or flow that could cause this?

Nope.

 

[malibu795]

Iirc There's a slip bearing in the tail shaft. Could be worn out.
I've put small dings in driveshaft this make it slightly out of balance and wear that bearing out