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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: k10Ryan79 on March 03, 2017, 08:32:48 pm

Title: Manual Trans/ Transfer Case oil
Post by: k10Ryan79 on March 03, 2017, 08:32:48 pm

I have a 1979 Chevy K10 with the manual trans and the 205 transfer case. what oil would you guys recommend running in them? thanks! 

Title: Re: Manual Trans/ Transfer Case oil
Post by: 1967KaiserM715 on March 03, 2017, 09:01:31 pm

80w90 or 75w90 gear oil for transmission,

For the 205, I am pretty sure gm started using atf in them around the late 70's, but you won't go wrong using the same oil as the transmission.


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Title: Re: Manual Trans/ Transfer Case oil
Post by: Sprinkler-Man on March 06, 2017, 08:59:47 pm

Don't use ATF in the 205. The bolt holes thread completely into the case and the fluid leaks out. I made this mistake with my 1980 NP 205

Title: Re: Manual Trans/ Transfer Case oil
Post by: Big Daddy on March 16, 2017, 05:27:27 pm

pretty sure its gear oil in the np205, trans fluid in the np208, 10w30 in the np203

Title: Re: Manual Trans/ Transfer Case oil
Post by: 1967KaiserM715 on March 17, 2017, 07:14:15 am

So GM put syncros in the 205 in the late 80's and used ATF from the factory, not late 70's. There is a little info regarding this scattered across the interwebs if your so inclined to search for it. Iirc it was '88-'91 in the 1 tons only for shift on the fly.


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Title: Re: Manual Trans/ Transfer Case oil
Post by: VileZambonie on March 17, 2017, 10:44:16 am

Both call for GL-5 80W90

The 203 calls for 10w30