I have a leak in my NV231HD transfer case.
I think I've narrowed it down to a seal in the middle of the unit.

(Sorry about always posting cell phone pics but my laptop hard drive crashed and I've been using my server and have no memory card reader for my camera on this system)
Not sure what this is called or how severe it is.
If this needs to be replaced (I would think so), how would I do that? Would it require removing the transfer case?

Also, does anyone know the size of the hex-hole in the transfer case drain/fill plugs? I want to check the condition and level of the fluid and keep it topped up until I can fix it. I've tried all the allen wrenches I have and they're too small.

 

I believe the drain plug on my NP231 was the same as on my NV3500 and it's 17mm.

You mean it's leaking between the 2 halves? It probably doesn't HAVE to be removed but it's not hard to do and it will be a lot easier to split the case on a work bench.

Actually looking at the picture more closley it looks like it's leaking between the tranny and t case. If it is yes it needs to be dropped. The old RTV needs to be scrapped off and apply a thin layer of RTV onto the tranny, let it cure for 15-20 minutes and bolt the t-case back up.

 

i thought there was actually a gasket that goes between the tranny and transmission...anyway, i would just take the transfer case out. much much easier!

 

There are also gaskets for diff covers but it's common place to just use RTV.

 

some people use rtv...some prefer gaskets. i use gaskets first...then if it still leaks, then i use rtv lol

 

So I should take it off and determine where the leak is from. If it's the mating surfaces of the tranny/transfer case, put on some RTV and put it back. If it's a seal in the transfer case housing, rebuild it.
Correct?
Will I need to drain fluids out of the tranny to remove the transfer case?

 

If the 46RE is like other auto trannys I've worked on, there is no rear seal on the 4wd model, the transfercase is what keeps the fluid in. So if that is the case, it's simply a leak between the 2 mating surfaces.

 

Alright, thanks. I'll crawl under it tomorrow and look some more. Try to clean it up and see where the fluid is leaking from after that.

 

the allen size is 10mm.
there is a seal between the transfer case and the transmission. thats why dodge started saying to put atf4 in the transfer case, that way if the seal goes out then you won't have dexron contaminate your transmission.
i believe the gears and chain will fall out if you try to take it apart on the truck. take it out and replace the seal on a bench.

 

Never mind I went and crawled under my truck and the drain and fill plugs for the t-case are standard hex heads.