Trans Fluid pouring out of np208

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
Im so Effing sick of this truck.

This is just one of many problems Ive been having. For months Ive had large amounts of trans fluid on my rear axle, shocks, bumper, tailgate, and it also covers any boat or trailer I pull behind me. I noticed fluid on the t case but also noticed that my trans pan was loose so I redid the gasket, and torqued the bolts down and have had no more problems out of the trans so it seems.

Today I got home from a 150 mile trip towing a lowboy and yet again its covered in trans fluid. Everything under the truck is. This isn't just a small leak.

So I start looking at the t case since it also houses trans fluid. I think its coming from the speedo gear assembly, because I just redid the gasket on the tail housing for the t case.

Months and months ago I thought Id check the level of the t case fluid so I unscrewed the upper fill plug and fluid started leaking out. I though wow I guess I overfilled it somehow (hard to do when it runs out the fill hole you are squirting it into).

So I screwed the plug back on and fast forward to now at least 4 months later and manymany miles, I haven't added or checked the fluid to the tcase at all. l

So I decided today to pull the upper cap again. Trans fluid POURS out. COVERS the ground.

So my question to you is, Is there a seal or something that blocks trans fluid from going between the trans and the t case that has failed??? Because someone on this site told me that fluid is not supposed to flow thru between the two.

I havenot checked my trans fluid level as of yet, but last time I redid the pan I topped it off and if it is low again when I do check it, it is a clear sign to me that somehow fluid is leaking into the t case and the tcase is blowing it out. What are your thoughts.

EDIT in this picture I have not removed the lower drain plug on the tcase. This all cameout of the upper fill hole

You must be registered for see images attach
 

yevgenievich

Full Access Member
Joined
Mar 1, 2014
Posts
4,819
Reaction score
3,400
Location
Place
First Name
Name
Truck Year
Year
Truck Model
Model
Engine Size
Size
There is a seal on the input between transmission and the t case. When failed, it fills the t case with fluid
 

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
Can anyone provide more info on this seal, or what all it takes to fix?
 

crazy4offroad

Equal Opportunity Destroyer
Joined
Jul 30, 2010
Posts
8,479
Reaction score
1,109
Location
West BY-GOD Virginia
First Name
Curt
Truck Year
1979
Truck Model
K-10
Engine Size
350/SM465/NP205
Unfortunately it requires dropping the t-case and driveshafts. There's an output shaft from the trans and an input shaft from the t-case with a large coupler between them and the seals ride on the coupler. I think there is also an output shaft seal in the tail of the trans as well, might as well change it too. That would require putting a jack under the trans and removing the adapter to get to it. Keep an eye on your trans fluid level, that's a lot of fluid to lose and you definitely don't want a burnt up trans added to the to-do list.
 

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
yeah, I've been adding trans fluid and wondering where it goes. This morning after the tcase fiasco I put two quarts in the trans again. Ok, Well Ill source the output and input seals and do that hopefully next weekend. Its the biggest issue with my truck right now and has priority.

Also, you know how I like to do extra when I have the chance. Is there anything in the t case I should replace? I was thinking about cracking it apart when I had it out. Is that an rtv seal or is there a gasket for the t case halves?
 

crazy4offroad

Equal Opportunity Destroyer
Joined
Jul 30, 2010
Posts
8,479
Reaction score
1,109
Location
West BY-GOD Virginia
First Name
Curt
Truck Year
1979
Truck Model
K-10
Engine Size
350/SM465/NP205
Yeah there will be a gasket on both sides of the adapter/mount. They can get under a lot of pressure so RTV isn't the best way to go.
 

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
Thanks, but I meant about cracking the transfer case in half. Is there anything in there worth changing out or looking at when I take the case out of the truck
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,356
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
That output seal doesn't look like a seal at all.

That t-case input seal should be the one that keeps the trans fluid from pushing into the t-case.
 

1low4x4

Full Access Member
Joined
Feb 14, 2011
Posts
2,409
Reaction score
716
Location
Texas
First Name
Nick
Truck Year
1984
Truck Model
K10
Engine Size
5.7
I just read on another site that there is no output shaft seal on a 4x4 trans, there is only the input seal of the case. Then there is a gasket between the case and adapter, and an o ring between trans and adapter
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,356
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
I just read on another site that there is no output shaft seal on a 4x4 trans, there is only the input seal of the case. Then there is a gasket between the case and adapter, and an o ring between trans and adapter

Sounds right. I couldn't remember for sure about the trans output. The seals Curt had mentioned before (the ones on the coupler) are on the np205 adapters.
 

Forum statistics

Threads
44,175
Posts
950,959
Members
36,303
Latest member
Spider
Top