Leak somewhere between transmission and transfer case

[David Cleveland]

So I have an 83 W150 with 318/727/NP208

I'm noticing that my transfer case fill plug gushes fluid out when opened as opposed to a slight dribble when properly filled. This indicates a leak somewhere between, the transmission, adapter, and transfer case. Has anyone else experienced this and what ended up being the issue?

 

[u2slow]

The tcase input seal has failed. Not sure if the 727 uses an output seal or not.

How fast does the tcase overfill? If it's slow, you can manage the levels every engine oil change or so. Ultimately you need to change the seal.

 

[David Cleveland]

I got it apart. After examining everything it has to be that tc seal. Fluid flows freely between the transmission and the adapter. There is a bearing in the adapter that is lubricated by the transmissions fluid. The shaft of the tc goes inside the adapter a little ways and is the only thing that has a seal preventing fluid transfer from the adapter to the tc. So I’ll replace the tc input seal, the gasket between everything, and put it back together. It’s good 7-8 hours of work. Not a fun job but beats working on any newer vehicle.

 

[David Cleveland]

I can say in all honesty this isn't a terrible job. The transfer case is heavy and hard to maneuver but with a good transmission jack, it's doable. Mostly it's just time-consuming and finding the proper gaskets was a chore. I found the transmission to Adapter gasket in Jasper, AL, and the adapter to Transfer case at Weller truck parts in Grand Rapids Michigan. Both were original Mopar parts and came in the original, super old packaging. All in all, I wouldn't want to do it again but it wasn't a nightmare job.