NP205 install question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**derotoreut** · 07-31-2019, 06:32 PM

I've searched this with no luck. Do I need to put some type of silicone or RTV on the adapter-to-NP205 bolts. Some of these bolt holes are open to oil side. Thanks.

sweetk30 · 07-31-2019, 06:51 PM

first off there needs to be the correct gasket between the 205 case and adapter or you WILL break the adapter when bolts go tight .

and if me i would put a little rtv on the threads to seal them up were there a open hole in to the case just so its less of a leak point down the road .

**derotoreut** · 07-31-2019, 08:21 PM

Yes I have the proper gasket to go between the adapter and transfer case. Actually I'm doing an engine swap going from 307/SM465/NP205 to 5.3L LM7/4L60E/NP205. I'm using Advanced Adapters for the NP205 10-spline to 4L60E. They sent me the gasket. I have read that you must use the gasket, but I wasn't sure about sealing the bolts. If I couldn't find anything I planned to put some RTV on the bolts. I also read several posts about NOT using the NP205 torque mount that installs to the frame. I'm not sure about that one yet.

sweetk30 · 07-31-2019, 10:35 PM

just making sure you know the gasket was all .

and most now say no frame to t-case mount it can brake the trans tail housing in frame flex off road stuff . better to do the newer trucks brace rod from t-case to bell housing bolt / stud .

**kwmech** · 07-31-2019, 11:01 PM

Pic one or 2 holes that go through into the oil cavity and install a stud. Makes it easier when installing and trying to line things up. Those things are 150 lbs.. ish

**jeffahart** · 08-01-2019, 12:00 AM

I think it's the 465 side of the adapter that has a couple of through bolts at the center. And the PTO covers each have a couple through bolts too.

I use just use a bit of head bolt thread sealant.

And like said, be damned sure you have the correct tolerance gasket for the adapter.

J

**derotoreut** · 08-01-2019, 03:36 PM

Quote:

Originally Posted by jeffahart

I think it's the 465 side of the adapter that has a couple of through bolts at the center. And the PTO covers each have a couple through bolts too.

I use just use a bit of head bolt thread sealant.

And like said, be damned sure you have the correct tolerance gasket for the adapter.

J

Put it this way... I have two gaskets. One from a transmission shop and the other from Advanced Adapters to use with their 4L60E/NP205 adapter. They better be right. I have no way to tell if they're not.

1972ochre4x4 · 08-02-2019, 08:06 AM

I use Indian Head sealer on bolts going into oil passages

**derotoreut** · 08-02-2019, 11:41 AM

Quote:

Originally Posted by 1972ochre4x4

I use Indian Head sealer on bolts going into oil passages

That's a new one. Isn't that low temp shellac type gasket material?

1972ochre4x4 · 08-02-2019, 11:56 AM

Works great on freeze plugs too

07-31-2019, 06:32 PM	#1
derotoreut Roto Reuter thats the name... Join Date: Feb 2010 Location: Darien, NY Posts: 1,848	NP205 install question I've searched this with no luck. Do I need to put some type of silicone or RTV on the adapter-to-NP205 bolts. Some of these bolt holes are open to oil side. Thanks. __________________ ~ Dan My 70 K10 SWB build:http://67-72chevytrucks.com/vboard/s...d.php?t=782232 My 71 SWB build:http://67-72chevytrucks.com/vboard/s...d.php?t=651394 1970 SWB Fleet K10 4X4, 5.3L LM7, 4L60E, Dakota Digital RTX, Vintage Air, Ididit tilt 1971 SWB Fleet C10 - Original SWB Arizona truck, new custom restoration project "Kick out your motor and drive while you're still alive - kick it out!" - Heart 1977

07-31-2019, 06:51 PM	#2
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: NP205 install question first off there needs to be the correct gasket between the 205 case and adapter or you WILL break the adapter when bolts go tight . and if me i would put a little rtv on the threads to seal them up were there a open hole in to the case just so its less of a leak point down the road . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.

07-31-2019, 08:21 PM	#3
derotoreut Roto Reuter thats the name... Join Date: Feb 2010 Location: Darien, NY Posts: 1,848	Re: NP205 install question Yes I have the proper gasket to go between the adapter and transfer case. Actually I'm doing an engine swap going from 307/SM465/NP205 to 5.3L LM7/4L60E/NP205. I'm using Advanced Adapters for the NP205 10-spline to 4L60E. They sent me the gasket. I have read that you must use the gasket, but I wasn't sure about sealing the bolts. If I couldn't find anything I planned to put some RTV on the bolts. I also read several posts about NOT using the NP205 torque mount that installs to the frame. I'm not sure about that one yet. __________________ ~ Dan My 70 K10 SWB build:http://67-72chevytrucks.com/vboard/s...d.php?t=782232 My 71 SWB build:http://67-72chevytrucks.com/vboard/s...d.php?t=651394 1970 SWB Fleet K10 4X4, 5.3L LM7, 4L60E, Dakota Digital RTX, Vintage Air, Ididit tilt 1971 SWB Fleet C10 - Original SWB Arizona truck, new custom restoration project "Kick out your motor and drive while you're still alive - kick it out!" - Heart 1977

07-31-2019, 10:35 PM	#4
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: NP205 install question just making sure you know the gasket was all . and most now say no frame to t-case mount it can brake the trans tail housing in frame flex off road stuff . better to do the newer trucks brace rod from t-case to bell housing bolt / stud . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.

07-31-2019, 11:01 PM	#5
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,387	Re: NP205 install question Pic one or 2 holes that go through into the oil cavity and install a stud. Makes it easier when installing and trying to line things up. Those things are 150 lbs.. ish

08-01-2019, 12:00 AM	#6
jeffahart Senior Member Join Date: May 2012 Location: Scottsdale, AZ Posts: 1,881	Re: NP205 install question I think it's the 465 side of the adapter that has a couple of through bolts at the center. And the PTO covers each have a couple through bolts too. I use just use a bit of head bolt thread sealant. And like said, be damned sure you have the correct tolerance gasket for the adapter. J __________________ White K20

08-02-2019, 08:06 AM	#8
1972ochre4x4 Registered User Join Date: Apr 2019 Location: Florida Posts: 23	Re: NP205 install question I use Indian Head sealer on bolts going into oil passages

08-02-2019, 11:56 AM	#10
1972ochre4x4 Registered User Join Date: Apr 2019 Location: Florida Posts: 23	Re: NP205 install question Works great on freeze plugs too



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