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Old 09-15-2020, 08:29 PM   #1
tinman_local2
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Rockwell T221 mounting adapter seals

Anyone have a part number for the two seals in the adapter that goes between the sm465 and Rockwell t221 transfer case. Local parts stores are having trouble getting me the right seals. The dimensions are 2.62" OD, 1.875" ID for both seals, but the one on the trans side is 1/2" wide and the other is like 5/16" wide.
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Old 09-15-2020, 08:40 PM   #2
gmc684x4
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Re: Rockwell T221 mounting adapter seals

It is sm420 and the Rockwell t221 tcase not a sm465

I do not recall the seal part numbers as it was in the early 90s i had mine apart last i do love the little bit extra low gear you get out of this pair over the 465 205 combo
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Old 09-15-2020, 09:11 PM   #3
tinman_local2
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Re: Rockwell T221 mounting adapter seals

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Originally Posted by gmc684x4 View Post
It is sm420 and the Rockwell t221 tcase not a sm465

I do not recall the seal part numbers as it was in the early 90s i had mine apart last i do love the little bit extra low gear you get out of this pair over the 465 205 combo
I stand corrected on the trans number. SM 420 trans.
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Old 09-15-2020, 09:36 PM   #4
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Re: Rockwell T221 mounting adapter seals

Hold the phone! The T-221 was most certainly mated with the SM465 in '69.
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Old 09-15-2020, 09:44 PM   #5
gmc684x4
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Re: Rockwell T221 mounting adapter seals

I have had 4 69 trucks they all had a sm420 with t221 tcase only trucks i seen with sm465 and a np205 tcase are 70 and newer or trucks that had been converted

One easy tell tail is sm420 front driveshafts is it has only 2 u joints
Where the sm465 setups have 3 u joints two make up a cardan joint

https://www.rockauto.com/en/catalog/...haft+seal,8416
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Old 09-15-2020, 10:11 PM   #6
tinman_local2
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Re: Rockwell T221 mounting adapter seals

Mine has 3 u joints for the front shaft. Either way I'm looking for the seal numbers for the adapter mount. Pretty sure it's a sm465.
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Old 09-15-2020, 11:24 PM   #7
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Re: Rockwell T221 mounting adapter seals

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Originally Posted by palallin View Post
Hold the phone! The T-221 was most certainly mated with the SM465 in '69.
Correct. And I have the seal # for the adapter.

http://67-72chevytrucks.com/vboard/s...d.php?t=796874
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Old 09-15-2020, 11:28 PM   #8
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Re: Rockwell T221 mounting adapter seals

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Originally Posted by tinman_local2 View Post
Anyone have a part number for the two seals in the adapter that goes between the sm465 and Rockwell t221 transfer case. Local parts stores are having trouble getting me the right seals. The dimensions are 2.62" OD, 1.875" ID for both seals, but the one on the trans side is 1/2" wide and the other is like 5/16" wide.
. I used the same seal on both ends. See above. Worked fine and does not leak.
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Old 09-16-2020, 03:39 AM   #9
'68OrangeSunshine
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Re: Rockwell T221 mounting adapter seals

GM did produce trucks with an SM465/Rockwell T221 transmission/transfer case in Model Year 1968. They may have also gone into MY '69 on GMCs and Canadian trucks.
I know there is such an animal, I have one as a core.
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Old 09-16-2020, 07:53 AM   #10
tinman_local2
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Re: Rockwell T221 mounting adapter seals

Hotcorner that seal is for a 2" shaft size. My coupler is 1.875". Do you recall what OD your coupler is?
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Old 09-16-2020, 09:15 AM   #11
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Re: Rockwell T221 mounting adapter seals

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Originally Posted by '68OrangeSunshine View Post
GM did produce trucks with an SM465/Rockwell T221 transmission/transfer case in Model Year 1968. They may have also gone into MY '69 on GMCs and Canadian trucks.
I know there is such an animal, I have one as a core.
Interesting. My buddy and I both have 69 GMC K25s. Both had SM465/T-221 combo.

Ill measure the coupler. I have an extra one in the garage.
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Old 09-16-2020, 09:19 AM   #12
palallin
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Re: Rockwell T221 mounting adapter seals

Don't have a pic of the SPID handy, but both the SM465 and the T221 are on it: '69 Chevy K-10.
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Old 09-16-2020, 07:43 PM   #13
tinman_local2
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Re: Rockwell T221 mounting adapter seals

The seal part number for the transfer case mounting adapter are SKF brand 18581. It requires two seals. The number for the drive shaft seals on the transfer case are SKF 17387 or National 472164. Also requires two. Hope this helps someone in the future. All parts books or parts stores will tell you different. These are the numbers that cross reference to the seals that I removed. The measurements for the seals are 2.625" OD, 1.875" ID. The width really doesn't matter for this application.
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Old 09-16-2020, 09:09 PM   #14
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Re: Rockwell T221 mounting adapter seals

The OD for my sleeve is 2”.
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Old 09-17-2020, 07:46 AM   #15
tinman_local2
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Re: Rockwell T221 mounting adapter seals

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The OD for my sleeve is 2.
Mine is 1 7/8". I wonder why the difference.
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