Transfer Case -- I used the wrong fluid! What now?

[wyowrx]

So, the previous owner told me that my 88 had an NP208. I've been having noise issues with it, so I changed the fluid today. I used the Dexron ATF.

After looking at it some more and thinking that the fluid coming out definitely didn't look like ATF, I started researching what the NP208 should look like.

After comparing mine to pics on line, I'm pretty sure it's an NP205, which should take 90w gear oil instead of ATF. I plan to drain and fill it again with the 90w, but is there anything else I need to do? Flush? Disassemble??

Also, the shift pattern seems to be (top) 4h - 2h - neutral - 4l (bottom). Is this consistent with the NP205?

Here's a pic:

 

[Hogback Fabrication]

That's a 205 and atf was the specified fluid in the 80's. Most run gear oil but either is fine.

 

[wasted wages]

looks like a 205 to me.....gear oil....75-90w

a little ATF isn't going to hurt anything.....drain it and refill w/ gear oil..

 

[sweetk30]

x2 for both postings here already.

 

[wyowrx]

Thanks a lot for the fast replies. It was eating me up!

 

[sweetk30]

bonus is you got a 205 not a 208

 

[manchildau65]

Curious what you mean by "noise issues", 205's are all gears inside so they whine a lot, is that what you were worried about?

... and to reiterate what's already been stated, mine had ATF in it and I switched to 80w90, no problem running either (and congrats on the 205 instead of 208)

 

[wazzabie]

I think this is one of great debate... gear oil or ATF. I've seen the GM manual call for ATF some years and gear oil in other years.

Now if you are running an auto maybe it makes sense to go with ATF. I run ATF with my auto TH350-Np205 setup. Should one be concered about the oils getting mixed between the tcase ant tranny?

 

[70jimmy]

Agree with the others. definitely a 205. Rumor was that they had you use atf if you had an auto and gear oil if you didn't.

I have an auto and mine had atf in it when I bought it but I have been running gear oil since I got control of it.

 

[K5_Fla]

“”I think this is one of great debate... gear oil or ATF. I've seen the GM manual call for ATF some years and gear oil in other years.

Now if you are running an auto maybe it makes sense to go with ATF. I run ATF with my auto TH350-Np205 setup. Should one be concered about the oils getting mixed between the tcase ant tranny?”””””


I also have a TH350 and NP 205. I did have an issue with the gear oil and ATF mixing… bad seal cause the cross contamination. Not so bad for the NP205 if that happens… but pretty bad for the tranny.

ATF is fine for that NP 205…

 

[wyowrx]

Thanks guys! What about the shift pattern? With it in what I think is 2h, the front shaft won't move by hand.

This is what I think it is.

(top) 4h - 2h - neutral - 4l (bottom)

Way forward is definitely 4 wheel drive, but it doesn't feel like 4L at all. And neutral is definitely neutral. I haven't tried it in 4L, so that's the only variable. But there is a definite difference between what I think is 2h vs. what I think is 4h in the amount of drag in the front end I perceive.

Thanks again,
Jack

 

[K5_Fla]

on my 205... 2H and 4H is about a c unt hair apart... real small. Start out in N... then short jerk back should get you into 2H... you may need to play with it a little.
then turn driveshaft and see...

 

[KansasTwister]

I think it goes 2h 4h n then 4l if its like my 208.

 

[K5_Fla]

different than 208

 

[Fordum]

On a Ford, its: 4Hi all the way back toward the seat, 2Hi one notch toward the dash, then Neutral, then 4Lo all the way to the dash.

When I am going from bad stuff to solid ground and back, I leave the hubs turned, and stay in 2Hi. Then, when the rears start to slip, I back off the gas for a second, pull back on the lever and go.
Back on hard ground, back off the gas again, and kick the lever up one notch.

Having done that thousands of times over the past 34 years, I'm real clear about the shift pattern.

And yes, I know most folks would just leave it in 4Hi, but when you have been wrenching on one as long as I have, usually in mud, anything you can do to reduce the load on the drivetrain, you tend to do.....

Of course, that is for a God intended left hand front drive 205. Not sure what you rightys have.....

There are some pictures here of the shift medallion of a 205 on the knob that were posted when someone was looking for what one looked like.

It might have been Chief Brody for his, not sure right now.......

 

[Fordum]

OK, there are lots of threads discussing 205 shift patterns, but here is one that shows the knob.

http://coloradok5.com/forums/showthread.php?t=278543

 

[wazzabie]

OK, there are lots of threads discussing 205 shift patterns, but here is one that shows the knob.

http://coloradok5.com/forums/showthread.php?t=278543

Just to be clear my pic in that thread is of a NP 203 shift indicator plate.

 

[kennyw]

GM changed the spec from gear oil to tranny fluid only to squeeze out a bit higher MPG average from the fleet during the 80's. They also did not change anything internally to the tcase when they did this so there was a trade off in the life of the tcase because of it. However, these things will still last 3 lifetimes running ATF compared to 4 lifetimes running gear oil.

I would suggest you run what ever is in your transmission since it looks like it already leaks.

 

[Ned Kelly]

My 1985 K30 NP205 has had ATF in it since it left the factory. The factory literature that came with the truck indicates ATF for the t/c. I've had the truck over 25yrs and no t/c problems and I'm at 220,000 miles on it. ATF is fine.

 

[wyowrx]

Thanks for all the help. It turns out that in 2wd, the TC doesn't make any noise at all...!