NP205 gear oil capacity/type?
 

Just got our transfer case back from the shop,what to fill it before it goes back in.What is the capacity? Should it be 80-90 gear oil?
Thanks!

Usually, little more than 1/2 gallon of 80-90

Thanks Kw! Getting started on it right now.

I have dexron in my 205, is that bad? I was told you could use it. 80-90 is kinda thick at -30

I've heard automatic trucks should use tranny fluid, and manual trucks should use gear lube. It seems like a good idea if there is any leakage between the two. Any truth to this?

Using tranny fluid in all of mine.

Straight out of the factory service manual "SAE 80 GL-5 Gear Lubricant". It's what I ran in mine. I've seen and heard of auto tranny fluid in T-cases but sometimes it's in there because it has leaked through the adapter.

I forgot to mention that the NP205 is gear driven but most of the other T-cases are chain driven and I'm pretty sure that the recommened lube for them is tranny fluid. Funny thing is I can't find a quantity for the NP205 in the manual.

When I fill my NP205, I jack up the rear of the truck so I get in a little more. I use synthetic so I don't fear foaming.

I am installing my rebuilt 350 engine and 350 tranny this weekend in the 72 GMC K20 so which is the correct fluid? I was planning on synthetic 75-90 for the 205? Does two quarts of this sound correct?

Make sure whether your tranny calls for a GL-4 or GL-5 fluid, before you fill it.

A couple of other chvey boards I frequent have had this discussion and debate quite a few times. The end result?--- The 205s are damn near indestructible. Pretty much if you have a decent quality oil in them, they will last, some oils however may let the the t-case generate more noise than others but will not 'hurt' them. If you worry about a seal breach between the trans and t-case then use matching oils. Personally I am getting ready to use another NV4500 in a truck I am building with a doubler. I'll be using the synthetic for the NV in both the 203 and 205. My understanding is if you get any other type of oil in the NV other than the required synthetic it will destroy it.

The NP205 holds 2.5 qts. prior to 1980 they had 85w90. In 80 GM switched to dextron I suspect for fuel economy. But in 80 they also redesigned the ouput shaft to a slip yoke instead of a slip shaft driveshaft I don't know if the redesign required the fluid change. In really cold weather when warming up the engine, put the transfer case in neutral and trans in high gear it will limber it up pretty quick.

Re: NP205 gear oil capacity/type?
 

What if my truck is a 80 with a slip yoke? Also what is some ideas or recommandations for when the slip yoke leaks? Should a just replace the seal, replace the seal and yoke or I have heard of a conversion? There is a good amount of play back there and it is leaking kind nice.