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K5 Blazer - ATF getting into NP 205

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K5_Fla

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I have a T350 trans and NP 205 case. The NP 205 takes gear oil, which I use. I have changed out the transfer case fluid a few times lately and it always comes out red (ATF) I can smell the gear oil too, so it mixing together.
My trans fluid is somehow seeping back into my transfer case
What would cause this? Overfilling transmission?

I also noticed when I un screwed the top fill hole on the tcase – fluid stated coming out – a lot of it. So it’s also overfilling itself because I only fill it up until it starts to drip out of the top hole like I should. Any ideas?
 
Its a good idea to run atf in the 205 if you have a th350. Gear oil is prob going the other way past your seal into the tranny, which is not good.
 
I guess it ok to run ATF in the NP 205 - I have heard it can run both ATF or gear oil. So in my case... ATF it is because it's leaking back.
 
My 72 was doing the exact same thing. Dumped a can of Lucas in it about 2 years and 10,000 miles ago. Leaks a lot less now and still running strong.

Might be a good idea to change the fluid in your tranny and also your 205.
 
If you switch fluids, you are just delaying the inevitable. Making both fluids the same will eliminate the contamination, but the two gearboxes are not designed to have two vents and fillers.
Sooner or later, one box is going to starve the other.

If the 205 is over full now, that means that the TH350 is low.
Once the fluid starts running out the vent of the 205, the 350 is going to start having problems.

You need to check some of the threads here and make sure you have the right seals. There have been some advanced discussions about those seals as to number of lips, sizes and stuff.

Then, after you have the parts, pick a nice day, drain the 205, and get a GOOD transmission jack and strap the case to it.
You do not want to have to catch that case when it slips.

I'd make whole day of it. Replace the front and rear output shaft seals, check the pan gasket, and the linkage bushings.
Fix it so that you do not have to drop that unit or work on it for a long time.

As for using the same fluids, I got off on a tangent about that here once before. It was a truck that used gear lube in everything.
Not like your truck.
They were having the same problem, and I suggested sealing the vent in the 205, and removing all the interior shaft seals.
That way they could share the fluid.

Then I went one step farther and suggested a plumbing system where both axles, the transfer case and transmission could all use the same fluid with a small circulation pump, cooler, and spin on filter.

Then I went in and lay down until I felt better......................
 
You can do it Fordums way, or the right way as most people call it.:D

Or if its been 25 years since tranny or t-case was rebuilt and you have a sneaking suspicion you will be tearing it all apart pretty soon anyway. Dump some bandaid in it and run it til breaks. No sense dropping t-case if you're going to be taking transmission out a little later when it goes.
 
The 2 seals in the adapter are bad. It takes about 4 hours to put new ones in.
 
Fordum - I understand what you said, but don't a damn thing about tearing into a transfer case. Basically what you said processed into my brain as another $500-1000 to my trans shop. I’m kinda pissed off at my trans guy now - I already spent $1500 over the past 6 months getting seals and misc **** fixed in the transfer case and trans to fix leaks.
 
K5_Fla said:
Fordum - I understand what you said, but don't a damn thing about tearing into a transfer case. Basically what you said processed into my brain as another $500-1000 to my trans shop. I’m kinda pissed off at my trans guy now - I already spent $1500 over the past 6 months getting seals and misc **** fixed in the transfer case and trans to fix leaks.
Click to expand...


Good tranny shops are hard to find.
 
Blaaa blaa blaa

unbolt the transfer case take the adapter off replace seals put back together

022-1.jpg


021-1.jpg

this one has the seals in backwards
019-2.jpg
 
Well, in the first place, if you spent that much for seal replacement, 6 months ago and its already leaking, they ought to fix it for free.

But, you said that you were having problems with them.

I have been blessed with good transmission guys over the years. So I have not had to do that work myself.
I've done most every thing else over the years.

But, from what I read here, its not that big a job. If you can stand to be without the truck a couple of days, worst case, then I would go for it.
You should be able to do it in a day, but when you are finishing up at midnight so you can drive the truck the next morning for school or work, that is when things go bad or you get hurt.

A long time ago in Orlando, there was a combination parts house and rent-a-bay shop. As I remember, their hours were something like 6 to 10 weekdays, 6 to midnight on Saturday, and they stayed open to 3 or 4 Sunday night/Monday morning.
They said they did a lot of business after midnight on Monday morning from folks that started projects on Saturday and had to get it going for Monday morning.
 
Here’s the deal….. I dropped the truck off to a different shop to take a look as I’m done dealing with the other shop . The new guys have a good rep around town and seem like they know their stuff. They are also a Delco/GM shop. First thing they found is that seal was in backwards. I’m also missing some kind of support bracket on the upper passenger side of the tcase.

Then is gets worse…. Found out I have my turbo 350 trans is for a 2 wheel drive – it’s a 4x2 case. Apparently the PO used a 2 wheel drive T350….wonderful.

He said they could fix it up as is… all new seals and bands while they had it apart. But I should probably get a 4x4 case for the trans and get everything correct now. With my truck being a 4x4 and running 35 swampers it’s a matter of time before something happens.

Do you agree? I see this whole deal costing another $1,500 easy…. What pisses me off is the original Transmission guy never mentioned anything about me having a 2 wheel drive case. He worked on my truck 3 different times. And he is supposed to be the best… has a real big and busy trans shop in GA..that’s all he does. He also has knows a lot about big mud trucks.. he has a sweet old chevy on 40's. I ought to get set his f ing shop on fire!
 
K5_Fla said:
Then is gets worse…. Found out I have my turbo 350 trans is for a 2 wheel drive – it’s a 4x2 case.
Click to expand...

Either you or your trans guy has a sense of humor. A two wheel drive transfer case? If this is not a joke, then the second place is pulling your leg. Im gonna venture to say that there's no such thing as a two wheel drive transfer case.

Maybe the guy meant a 2wd trans adaptor?
 
bp71k5 said:
Either you or your trans guy has a sense of humor. A two wheel drive transfer case? If this is not a joke, then the second place is pulling your leg. Im gonna venture to say that there's no such thing as a two wheel drive transfer case.

Maybe the guy meant a 2wd trans adaptor?
Click to expand...

2wd transmission case, as in, not a K case.
It's not really that big of an issue, the K case is a little stronger but doesn't warrant getting a K case if your tranny is OK now.
 
If you happen to find a mint 4x4 case to work with, great! Otherwise it really doesn't matter, put the proper inspection cover (6 bolt) and braces and you will be fine.
 
Yes.. transmission case...lol. Ok.. I guess I will tell them to leave it as is and just reseal what I have..
 
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