2004 chevy suburban AWD.

[Junior Lepard]

I have a 2004 Chevy Suburban all wheel drive I went to change my transfer case fluid and it was like I open the tranny drain plug is that an open transfer case so the transmission filled it and its own tranny takes Dex 3 transfer case takes sex 3. No burn smells. Just nice red fluid. Came out.  Amd I opened the fill plug on transfer case. I may have dumped a qrt out be for I hurry up and put the plug back in so I guess my question is is the all-wheel-drive and open transfer case

[Jsdirt]

Most modern transfer cases take ATF. Perfectly normal, as is the giant blob of metal shards stuck to the magnet after it's first ever oil change.

 

They should be sealed. If the transfer case fluid level is over and above the fill hole, then it's leaking from the transmission. That's why you should always remove the fill plug first, before doing an oil change.

Edited June 18, 2020 by Jsdirt

[Junior Lepard]

So I can only come across a big gasket be tween the too is that all that needs to be done. Just separate the too put the new gasket in put it back together and also would it be would it hurt the transfer case to be over full like that cuz I need to take it out like an hour-and-a-half trip

[davester]

There's a gasket for that adapter plate, but that isn't the problem.  There is a seal on the output shaft of the transmission, and a seal on the input shaft of the transfer case, that probably should be replaced.

[Doug_Scott]

Check your automatic transmission fluid level.  If it is good, then you can be pretty well assured that the seals are not leaking between the two cases.  If you are leaking fluid from that one gasket you mention, pretty sure that is a good indicator that the seal on either the output shaft of the transmission or the seal on the input shaft of the transfer case, or both are leaking.  If the fluid from the transmission is leaking into the transfer case, the level of the transmission oil will be dropping with no external leak.  The seal on the output shaft is not holding pressurized oil in, it is preventing "loose" oil from seeping out.  Same as the seal on the input shaft of transfer case.

[Jsdirt]

Years ago I had a lemon of a '00 GMC Jimmy - worse than the Silverado if you can believe that one, but I digress. This one was losing tranny fluid with zero external leaks, and the transfer case was at the perfect level every time it was checked. Wasn't until I got so sick and tired of the constant failures and decided to dismantle and part out the vehicle, did I find the fluid was passing though a failed 4x4 switch, and getting drawn up into the vacuum lines, filling up the vacuum canister, and eventually being drawn into the intake and burned! Only when I removed the vacuum canister and it felt much heavier than it should, was the problem revealed. All the lines up to the intake were coated in ATF!

 

Another fantastic engineering brainstorm courtesy of GM ... General Mess ...

[Doug_Scott]

30 minutes ago, Jsdirt said:

Years ago I had a lemon of a '00 GMC Jimmy - worse than the Silverado if you can believe that one, but I digress. This one was losing tranny fluid with zero external leaks, and the transfer case was at the perfect level every time it was checked. Wasn't until I got so sick and tired of the constant failures and decided to dismantle and part out the vehicle, did I find the fluid was passing though a failed 4x4 switch, and getting drawn up into the vacuum lines, filling up the vacuum canister, and eventually being drawn into the intake and burned! Only when I removed the vacuum canister and it felt much heavier than it should, was the problem revealed. All the lines up to the intake were coated in ATF!

 

Another fantastic engineering brainstorm courtesy of GM ... General Mess ...

Modulator valves used to do the same thing.  Never enough oil to smoke or foul plugs, but enough to notice on the dipstick. 

[Junior Lepard]

So this is some s*** I pulled the transfer case and the connector housing and there is no seals in the transmission and there never was it's an open rear if I blow on the vacuum hose I can pour fluid out of it now this is out of the back of the transmission where the output shaft is so did I do all this work for nothing from the look of it it looks like it's an open transmission but there is a seal on the transfer case on the input shaft but I do know when I drained it I drained probably I don't know 6 quarts out of it I pulled the upper plug and it poured out like I was changing transmission fluid out of the tranny pan

[Junior Lepard]

There is another picture but it won't let me upload at the bottom of that transmission picture is a tiny hole which allows transmission fluid to come through I supposed to fill up the housing of that so it doesn't go bad rust but the transfer case was well well well over full when I pulled the fill plug it just drained and drained and drained but I did notice if I blow on one of the vacuum lines coming from the top of the transmission that goes into the transfer case I can blow tranny fluid out of the back of the tranny out of that hole that allows it

[Jsdirt]

There should be a gasket and a big o-ring there, like this: https://globaltransmissionparts.com/4l60e-4l65e-4x4-extension-housing-gasket-seal-kit-1998-up-15724744/?gclid=EAIaIQobChMI4dXngceO6gIVTL7ACh14UAtzEAQYASABEgLbxPD_BwE

 

If nothing was there, it's possible someone slapped that trans together before you owned it.