T-case adaptor Q - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Class of 69 · 09-08-2003, 06:54 PM

I have a friend who is installing a TH400 into his 4x4, but isn't sure yet which t-case has. He needs an adaptor. Will the same one mate his 400 to a 205, 203, 208?? He will be verifying his t-case soon to purchase an adaptor, but if it fits all NP cases, does anyone have one, with the sleeve, to sell? Thanks!!!

Blazer1970 · 09-08-2003, 07:10 PM

Basically, the adapters are all different. Any time you have a different t-case OR transmission, the adapter changes. You need the adapter that goes with your particular t-case/tranny combination. With an NP205/TH400, no sleeve is used. The tranny output shaft engages directly with a female input gear in the transfer case (32 spline).

Class of 69 · 09-08-2003, 07:15 PM

OK, I should have also mentioned the TH is out of a 2wd. I'm assuming he will also need a different tailhousing, and maybe an output shaft ??

**Richard** · 09-08-2003, 09:31 PM

I have a brand new TH400-205 adapter available if your friend is interested.

**kwmech** · 09-08-2003, 10:56 PM

Quote:

Originally posted by Class of 69
OK, I should have also mentioned the TH is out of a 2wd. I'm assuming he will also need a different tailhousing, and maybe an output shaft ??

You MAY have to replace depending on the length of the shaft, some of them will slide right together. the biggest problem was stated before in that the t-case will need to be a 32 spline input which may require an input gear, bearing, and the correct snap rings also some machining, depending on what t-case you are starting with. I also have all the parts required for doing the swap.

Class of 69 · 09-09-2003, 07:21 PM

I didn't see him at work today, but I know he had a TH350 in it before, so I assume that is the t-case he intends to use with the TH400. kwmech, why don't you PM me with what you have, and a price, and I can give it to him next time I see him. Thanks

70Chevy4x4Nut · 09-12-2003, 07:32 AM

If you get a NP205 that was coupled to a manual or a TH350, you will have to buy an aftermarket adapter to fit it. You cannot just change the input gear and shaft since the bearing housing and input shaft was bigger on a 205 that had a TH400.

**kwmech** · 09-12-2003, 09:38 PM

You can put the parts in AFTER you machine out the front of the case for the larger bearing, been doing it for every bit of 10 years now because of the rarity of the 400/205. Never heard of any aftermarket adaptors myself.

70Chevy4x4Nut · 09-12-2003, 11:12 PM

I've heard of Advance Adapters that sells many kind of adapters that can couple trannys and NP's together that normally didn't come that way from the factory, without any mods to the Transfer case. They are very pricey though.

**Richard** · 09-13-2003, 01:22 AM

The adapter that AA sells for this conversion is a new input gear, the larger bearing and an exact copy of the GM adapter. You do have to disasemble and machine the case out for the larger bearing just as kwmech says.

70Chevy4x4Nut · 09-13-2003, 06:38 AM

Thanks for the correction. I guess I didn't look at all the footnotes on their site. Sorry

09-08-2003, 06:54 PM	#1
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	T-case adaptor Q I have a friend who is installing a TH400 into his 4x4, but isn't sure yet which t-case has. He needs an adaptor. Will the same one mate his 400 to a 205, 203, 208?? He will be verifying his t-case soon to purchase an adaptor, but if it fits all NP cases, does anyone have one, with the sleeve, to sell? Thanks!!! __________________ 69 GMC K10 ..some restoration required....still.. Last edited by Class of 69; 09-08-2003 at 07:12 PM.

09-08-2003, 07:10 PM	#2
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,507	Basically, the adapters are all different. Any time you have a different t-case OR transmission, the adapter changes. You need the adapter that goes with your particular t-case/tranny combination. With an NP205/TH400, no sleeve is used. The tranny output shaft engages directly with a female input gear in the transfer case (32 spline). __________________ Tim

09-08-2003, 07:15 PM	#3
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	OK, I should have also mentioned the TH is out of a 2wd. I'm assuming he will also need a different tailhousing, and maybe an output shaft ?? __________________ 69 GMC K10 ..some restoration required....still..

09-08-2003, 09:31 PM	#4
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,881	I have a brand new TH400-205 adapter available if your friend is interested. __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

09-09-2003, 07:21 PM	#6
Class of 69 Registered User Join Date: Mar 2003 Location: Stillwater MN Posts: 1,166	I didn't see him at work today, but I know he had a TH350 in it before, so I assume that is the t-case he intends to use with the TH400. kwmech, why don't you PM me with what you have, and a price, and I can give it to him next time I see him. Thanks __________________ 69 GMC K10 ..some restoration required....still..

09-12-2003, 07:32 AM	#7
70Chevy4x4Nut Registered User Join Date: Dec 2002 Location: TX Posts: 311	If you get a NP205 that was coupled to a manual or a TH350, you will have to buy an aftermarket adapter to fit it. You cannot just change the input gear and shaft since the bearing housing and input shaft was bigger on a 205 that had a TH400.

09-12-2003, 09:38 PM	#8
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,628	You can put the parts in AFTER you machine out the front of the case for the larger bearing, been doing it for every bit of 10 years now because of the rarity of the 400/205. Never heard of any aftermarket adaptors myself.

09-12-2003, 11:12 PM	#9
70Chevy4x4Nut Registered User Join Date: Dec 2002 Location: TX Posts: 311	I've heard of Advance Adapters that sells many kind of adapters that can couple trannys and NP's together that normally didn't come that way from the factory, without any mods to the Transfer case. They are very pricey though.

09-13-2003, 01:22 AM	#10
Richard Senior Member Join Date: Dec 1999 Location: Southern California Posts: 2,881	The adapter that AA sells for this conversion is a new input gear, the larger bearing and an exact copy of the GM adapter. You do have to disasemble and machine the case out for the larger bearing just as kwmech says. __________________ Richard 1972 K10 Custom Deluxe SWB Fleetside My build https://67-72chevytrucks.com/vboard/...d.php?t=800746

09-13-2003, 06:38 AM	#11
70Chevy4x4Nut Registered User Join Date: Dec 2002 Location: TX Posts: 311	Thanks for the correction. I guess I didn't look at all the footnotes on their site. Sorry



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