T350/205 Transfer Case ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**blownz** · 03-09-2011, 08:41 PM

I recently bought a 72 K5 and it is leaking trans fluid out of the rear of the transfer case. It looks like it is coming out a vent or coming out of the rear seal. I had a 84 K10 with 700R/208 combo, not familar with the older ones. Does the 205 use 90w oil in it or does it share dextron with the trans. Is it possible that somehow the dextron is leaking into the 205 and leaking out. It goes through a bout a qt a week. Any thoughts?

Wayne

snj8198 · 03-09-2011, 08:59 PM

Sounds like the tcase is full of ATF due to a leaky seal between the trans and tcase. I've heard multiple different stories of oil use, but my vote is ATF in the trans and 80-90w in the tcase.

-steve

DirtyLarry · 03-09-2011, 09:38 PM

Ooooo……Nice Blazer!

I also agree that the adapter seals need to be replaced. I bet you have a film of slime on your window too. My old ’72 Blazer used to do that and my K10 had that happen when it was a TH350/205 years ago.

Below are the seals (blue) that need to be changed inside the transercase adapter. There is also one o-ring on the Th350 tail shaft that should be replaced while you have it apart. It is also a good idea to smear some sealant to the inside of the adapter sleeve to help seal it that much more. Heck, while you have it apart you might as well order the $23 NP205 reseal kit from National Drivetrain as it will include everything you will need and much more.

I also agree that the 205 should have 80W-90 or at least 75W-90.

**blownz** · 03-09-2011, 09:49 PM

Thanks, that is what was in the back of my mind. Looks like I will seperate and see where that goes!

Wayne

TATE228 · 03-22-2011, 06:36 PM

That blazer is all messed up. better give it to me.

03-09-2011, 08:41 PM	#1
blownz Active Member Join Date: Mar 2005 Location: Annapolis, MD Posts: 183	T350/205 Transfer Case ? I recently bought a 72 K5 and it is leaking trans fluid out of the rear of the transfer case. It looks like it is coming out a vent or coming out of the rear seal. I had a 84 K10 with 700R/208 combo, not familar with the older ones. Does the 205 use 90w oil in it or does it share dextron with the trans. Is it possible that somehow the dextron is leaking into the 205 and leaking out. It goes through a bout a qt a week. Any thoughts? Wayne Attached Images

03-09-2011, 08:59 PM	#2
snj8198 Registered User Join Date: Feb 2007 Location: Star Valley, WY Posts: 2,038	Re: T350/205 Transfer Case ? Sounds like the tcase is full of ATF due to a leaky seal between the trans and tcase. I've heard multiple different stories of oil use, but my vote is ATF in the trans and 80-90w in the tcase. -steve __________________ Steve 1971 GMC Longbox. Full Roller Stroker 489 w/ FiTech EFI, Chris Straub Cam/NV4500/205/D60/14B w. Grizzly Locker and 4.11's. 2" Lift on 33's

03-09-2011, 09:38 PM	#3
DirtyLarry Windy Corner of a Dirty Street Join Date: Jun 2003 Location: Pueblo West, Colorado Posts: 2,926	Re: T350/205 Transfer Case ? Ooooo……Nice Blazer! I also agree that the adapter seals need to be replaced. I bet you have a film of slime on your window too. My old ’72 Blazer used to do that and my K10 had that happen when it was a TH350/205 years ago. Below are the seals (blue) that need to be changed inside the transercase adapter. There is also one o-ring on the Th350 tail shaft that should be replaced while you have it apart. It is also a good idea to smear some sealant to the inside of the adapter sleeve to help seal it that much more. Heck, while you have it apart you might as well order the $23 NP205 reseal kit from National Drivetrain as it will include everything you will need and much more. I also agree that the 205 should have 80W-90 or at least 75W-90. __________________ Current vehicle collection: 1978 Chevrolet K10, 8.1L, NV4500, NP205 1989 Chevrolet Suburban, 8.1L, NV4500, NP241 1993 Chevrolet C1500 Sportside, TBI 7.4L, 4L60E 2001 Chevrolet K2500HD, Ext Cab, SWB, 8.1L, ZF 6 speed 2014 Chevrolet Impala LTZ 3.6L Vortec 8.1L because life is too short to tolerate underpowered vehicles Instagram

03-09-2011, 09:49 PM	#4
blownz Active Member Join Date: Mar 2005 Location: Annapolis, MD Posts: 183	Re: T350/205 Transfer Case ? Thanks, that is what was in the back of my mind. Looks like I will seperate and see where that goes! Wayne

03-22-2011, 06:36 PM	#5
TATE228 Registered User Join Date: Dec 2003 Location: lake forest park, Washington Posts: 266	Re: T350/205 Transfer Case ? That blazer is all messed up. better give it to me. __________________ -1971 K20 350/sm465 -2004 1500



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