Tranny-Tcase fluid transfer

[scottystills]

Had some oil leaking from the tcase adapter, front and rear outputs, and the bottom of the rear inspection. Picked up the rear output shaft seal for the transmission, and the front and rear outputs on the tcase, figured I'd pull the tcase out and do some seal maintenance.

Hopped under and went to drain the tranny first, pulled the top plug then bottom and only a couple litres came out. Chalked it up to the thing leaking and moved onto the tcase. When I pulled the fill plug on the tcase to my surprise gear oil spewed out for a couple minutes. Not a slow drip, solid stream fill hole diameter. No visible water in it, looked like clean-ish gear oil. Finished draining it and nothing looks out of order but a little confused how the tcase could have filled so much? Obviously I couldn't have done that jamming oil bottles in...

Is there any way the tcase could have pushed gear oil into the tcase somehow? Going to take a closer look through the adapter when I get it dropped tomorrow.

Per sig, SM465 and NP205.

Thanks!

 

[sweetk30]

sounds like maybe pluged tranny vent . and when lube hot / expanded it pushed in to the tcase. I would prob be looking there first .

if you need 205 info/pics don't forget my 4l80/203/205 master build thread in the tech section .

 

[scottystills]

I would've thought worst case the tranny would vent through the shift tower? The shifter plugs the gap but it's far from air tight.

I'll definitely take a look at your tech thread though; haven't had to do the seals on the 205 since it's been in there but hoping it's fairly straightforward.

 

[neverdone]

What sweet k30 said. My 80 k5 had a plugged vent fitting in the brass fitting in the output seal housing.(205 slip yoke). It actually blew the seal out comeing down I70 one time. checking the transfer case and having a couple of quarts of fluid come out the fill hole is very disconcerting! The plugged vent fitting was causing the transfer case to suck transmission fluid through the seals in the adapter,(turbo 350), into the transfer case when it cooled down, causing a vacuume. the cure was a new fitting with a much larger id. Have pics on my phone of the fittings I could probably upload. Hope this helps.

 

[scottystills]

Yep I'm with you guys. Pulled the tcase and the vent seems ok, I can blow through it fairly easy. That rear housing, with the yoke off am I able to pull that entire thing off easy enough to drill it out larger, or are there steps involved that I can mess up?

Also getting to the tranny, I did pick up the output shaft seal, which I assume is the output seal at the back of the adapter (can you tell I've never pulled one of these apart before?). If it is, perfect. I didn't get time to compare them to existing as the rain started to fall. The rubber seal at the back of the adapter has about a 3/4" tear in it.

I did pull the adapter and there's a noticable gap where I imagine there shouldn't be (see below) at the output shaft. I'm also assuming that's a bearing but what the bleep do I know haha

 

[scottystills]

Sweetk30 after referring back to your tech article again, I see that it's probably not a great idea for me to try to pull that rear output off.

I will however make sure it's good and clean and leave it be.