Rockwell T221 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

blaskat · 04-09-2017, 05:13 PM

Can anyone explain the differences between the T221 N3, M6, and M7?
I need to replace mine, but can't seem to figure out exactly which I need.
Found an N3 but it isnt an exact match and the plate that shows the specs is missing from my original. Just don't want to make the same mistake twice. Oh, its out of a '62 Chevy K20.

**aerotruk63** · 04-09-2017, 05:36 PM

https://get.google.com/albumarchive/...AXM-D5HL1DfYIt

hopefully this link works.
when my 62 T221 broke, I called Rockwell directly and was transfered to the military division. I spoke to a really nice guy who sent me copies of the blueprints and a parts list breakdown.

BLT gmc · 04-09-2017, 07:48 PM

Meritor has a very nice manual on line for T-223 and T-221 series transfer cases. In this manual it states T-221-A released 10/55, T-221-A1 released 3/59, T-221-M released 2/59, T-221-M1 released 4/59, T-221-M3 released 12/59, M4 released 12/59, M6 released 3/61, M7 released 3/61, M8 released 3/61, N1 released 4/66, N2 released 4/66, N4 released 4/67, N5 released 4/67, N7 released 4/68. I realize some dufferent models were released in the same months, and I'm not sure of the exact differences. But hopefully this will give you some date line ideas.
Posted via Mobile Device

padresag · 04-09-2017, 10:26 PM

what is wrong with the one that you have?
ron

blaskat · 04-16-2017, 08:58 AM

Thanks. All good info. Destroyed mine. Teeth chewed through outer housing. Any leads on a replacement? Pretty sure mines a m6, but am still researching.

**aerotruk63** · 04-16-2017, 10:46 AM

Removed a transfer case from a frame I scrapped.
5875-S-513 on the casting. I have no history on it other than it seemed to be a pull truck at one time. Condition unknown.

**aerotruk63** · 04-16-2017, 10:53 AM

Sent TwoFiftyShifter to this yard
http://67-72chevytrucks.com/vboard/s...d.php?t=354945
His comments:
This is a yard a couple hours north of me I went to this saturday. The guy who owns it is named Bob Adler, for you guys in the northeast it's in Stephentown NY. 1/2 Hour east of Albany NY, right near the MA border. His number is (518) 733-5749.

04-09-2017, 05:13 PM	#1
blaskat Registered User Join Date: Apr 2017 Location: Portsmouth, NH Posts: 3	Rockwell T221 Can anyone explain the differences between the T221 N3, M6, and M7? I need to replace mine, but can't seem to figure out exactly which I need. Found an N3 but it isnt an exact match and the plate that shows the specs is missing from my original. Just don't want to make the same mistake twice. Oh, its out of a '62 Chevy K20. Attached Images

04-09-2017, 05:36 PM	#2
aerotruk63 Check The Champ, Demonstrator Join Date: Jun 2009 Location: Montreal,Quebec Posts: 6,627	Re: Rockwell T221 https://get.google.com/albumarchive/...AXM-D5HL1DfYIt hopefully this link works. when my 62 T221 broke, I called Rockwell directly and was transfered to the military division. I spoke to a really nice guy who sent me copies of the blueprints and a parts list breakdown. __________________ 1963 *Chevrolet Truck* Literature LINK: https://picasaweb.google.com/113840717762774560215 YouTube Channel with 20+ Original *Chevrolet Truck* Salesmen, Mechanics & Service Department Training Slideshows. https://www.youtube.com/results?sear...otruk63&page=1

04-09-2017, 07:48 PM	#3
BLT gmc Registered User Join Date: Feb 2014 Location: West Iowa Posts: 1,106	Re: Rockwell T221 Meritor has a very nice manual on line for T-223 and T-221 series transfer cases. In this manual it states T-221-A released 10/55, T-221-A1 released 3/59, T-221-M released 2/59, T-221-M1 released 4/59, T-221-M3 released 12/59, M4 released 12/59, M6 released 3/61, M7 released 3/61, M8 released 3/61, N1 released 4/66, N2 released 4/66, N4 released 4/67, N5 released 4/67, N7 released 4/68. I realize some dufferent models were released in the same months, and I'm not sure of the exact differences. But hopefully this will give you some date line ideas. Posted via Mobile Device

04-09-2017, 10:26 PM	#4
padresag Registered User Join Date: Feb 2008 Location: Sidney,b.c. Posts: 4,425	Re: Rockwell T221 what is wrong with the one that you have? ron

04-16-2017, 08:58 AM	#5
blaskat Registered User Join Date: Apr 2017 Location: Portsmouth, NH Posts: 3	Re: Rockwell T221 Thanks. All good info. Destroyed mine. Teeth chewed through outer housing. Any leads on a replacement? Pretty sure mines a m6, but am still researching.

04-16-2017, 10:46 AM	#6
aerotruk63 Check The Champ, Demonstrator Join Date: Jun 2009 Location: Montreal,Quebec Posts: 6,627	Re: Rockwell T221 Removed a transfer case from a frame I scrapped. 5875-S-513 on the casting. I have no history on it other than it seemed to be a pull truck at one time. Condition unknown. __________________ 1963 *Chevrolet Truck* Literature LINK: https://picasaweb.google.com/113840717762774560215 YouTube Channel with 20+ Original *Chevrolet Truck* Salesmen, Mechanics & Service Department Training Slideshows. https://www.youtube.com/results?sear...otruk63&page=1 Last edited by aerotruk63; 04-16-2017 at 10:53 AM.

04-16-2017, 10:53 AM	#7
aerotruk63 Check The Champ, Demonstrator Join Date: Jun 2009 Location: Montreal,Quebec Posts: 6,627	Re: Rockwell T221 Sent TwoFiftyShifter to this yard http://67-72chevytrucks.com/vboard/s...d.php?t=354945 His comments: This is a yard a couple hours north of me I went to this saturday. The guy who owns it is named Bob Adler, for you guys in the northeast it's in Stephentown NY. 1/2 Hour east of Albany NY, right near the MA border. His number is (518) 733-5749. __________________ 1963 *Chevrolet Truck* Literature LINK: https://picasaweb.google.com/113840717762774560215 YouTube Channel with 20+ Original *Chevrolet Truck* Salesmen, Mechanics & Service Department Training Slideshows. https://www.youtube.com/results?sear...otruk63&page=1



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