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Transfercase oilchange

ankarback

ankarback

1/2 ton status
Joined
Oct 8, 2002
Posts
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Location
Huddinge, Sweden
Hi

Just bought a -76 Blazer K5 and I´m wondering what kind of oil i should use in the tranfercase (NP 203).
The car is used a lot in mud and water so some maintainance i really nessesary.

Best regards

/Johan
 
is it the same for a 205?

Where's the stinkin fill hole?? And please dont tell me where the cable goes in. /forums/images/graemlins/smile.gif
 
So:
NP203=10W30
NP205=90wt
NP208=tranny fluid
NP241(or whatever else they put in K5's)=?

Are the top three right? What about the other?
 
Dies it really matter if gear lube is used in it? Mine has gear lube in it (I bought it that way) and it seems to work. Also, it's been converted to part-time, if that matters.
 
DO NOT USE GEAR OIL. The 203 must use 10-30 motor oil. To drain the unit pull the lower bolt on the cover on the back of the case. To refill squirt the oil into the fill hole halfway up the case. 80-90 + 203= kaboom.
 
The NP 205 uses 80w-90 gear lube. The fill plug is on the back halfway up the case and can be removed with a 9/16" open end wrench. Fill the case not more than 1/2" below the fill hole. You can squirt the oil in with a bottle or buy a pump, or go to the local quick lube and pay 19.95 to do a drain and fill service.
 
I have used gear lube in my 203 for more than 10 years, had no problems, the chain never stretched and everything was very silent.
I don't see a problem running gear lube in it, except the drag, which I didn't feel.
 
I've heard that gear oil in a 203 will cause the chain to wear out faster. I think it may also damage the oil pump.
 
What oil pump?
I rebuilt the 203 when I bought the truck, there was no pump.
And I reused the chain that was in it, and it had gear lube.
It was a 1 ton 203 though, with a one piece tail housing all cast iron, no aluminum parts.
 
np203 oil pump

The part about the chain wearing out faster is just what I have been told, I have no evidence of this being true. All I know is that my 205 is a lot stronger than my old 203.
 
it is a little disc the looks like it has been threaded and goes on the output shaft it pumps oil to the rear out put bearing
 
Oh that's a pump? well it was fine, and I never changed it.
By the way, gear oil is just thicker and slicker, so wear would be less on everything.
The type of pump this one has doesn't get affected by thicker oil, since it's not the sealed type ie: not compressing the oil, just sling it and making waves.
The chain was more than 20 years old, and I kept it and I drove it hard in a full time configuration for 5 years after that.
Believe me it's much smoother and I don't care about the parsitic losses ( drag from the thickness of the oil), if I did I wouldn't put 35" mud tires on it /forums/images/graemlins/smile.gif
 
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