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

*wolfthing2000* · 01-13-2005, 01:14 PM

I have heard both pros ( they are indestructable) and cons ( noisy, hard to find parts for) for the T221. How noisy are they realy and what are everyones opinions on this subject.
I have a questionable 205 that was transplanted into my 69 truck. In previous years I was given a 221 that I wasn't sure what I would do with. It seems to be in real good shape.
Attatched to the 221 is a SM420 ( the one used by GM before the SM465) These trannys are plentiful and I have access to some good parts.
Should I even think for another minute on using the old school stuff or go with rebuilding the SM465 and the NP205???
Thanks,
Dave

Rod · 01-13-2005, 02:32 PM

Noisier yes...pretty tough also. My brother had a 69 GMC 3/4 with a 454 and never had much for problems with it. He managed to get some parts for the 221. Gaskets, bearings and such also.

I would say the NP205 and 465 are preferred. If I was gonna spend my money rebuilding 1 of the 2 if both were in front of me, I would probably do the NP205 and 465.

1969 GMC · 01-13-2005, 03:40 PM

My GMC came with a T221 behind the SM465...now it has a NP205. It did a good job for me for about 11k or so miles, or a year as my DD. Then the front and rear seals both took a crap at the same time, which I still dont understand. I had to check the oil level every day, as it would leak alot. I didn't have time to pull it, as the truck was my dd and I went to school and work 6 days out of 7. One day I topped it off, left for school, and right as I got there I heard this nasty clanking. Yup, all the gear oil had pissed out of it. After that you could tell I had hurt some of the bearings, as it was even noisier than before (btw, the NP205 is about the same noise wise). It lasted for maybe a week, then on my way home from work (after topping it off yet again, I was carrying 6-7 quarts of gear oil with me at this point, as well as a large piece of cardboard to lay on under the truck), it locked up when I was going 55 mph. Not fun.

I took it out of the truck and took the pto cover off, and there was a few drops of gear oil left in it. The gear oil that was left was silver in color, and about 2/3 of the case's bearing balls were in the bottom. The gears dont look damaged but I have no clue why it locked up. Then I called up Meritor (who makes the parts for Rockwell tcases now, as well as brakes and axles for big trucks) and prices are just hideous compared to the 205. The choice was easy for me.

01-13-2005, 01:14 PM	#1
wolfthing2000 Account Suspended Join Date: Oct 2004 Posts: 1,276	T221 Rockwell Transfercase I have heard both pros ( they are indestructable) and cons ( noisy, hard to find parts for) for the T221. How noisy are they realy and what are everyones opinions on this subject. I have a questionable 205 that was transplanted into my 69 truck. In previous years I was given a 221 that I wasn't sure what I would do with. It seems to be in real good shape. Attatched to the 221 is a SM420 ( the one used by GM before the SM465) These trannys are plentiful and I have access to some good parts. Should I even think for another minute on using the old school stuff or go with rebuilding the SM465 and the NP205??? Thanks, Dave

01-13-2005, 02:32 PM	#2
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Noisier yes...pretty tough also. My brother had a 69 GMC 3/4 with a 454 and never had much for problems with it. He managed to get some parts for the 221. Gaskets, bearings and such also. I would say the NP205 and 465 are preferred. If I was gonna spend my money rebuilding 1 of the 2 if both were in front of me, I would probably do the NP205 and 465. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

01-13-2005, 03:40 PM	#3
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	My GMC came with a T221 behind the SM465...now it has a NP205. It did a good job for me for about 11k or so miles, or a year as my DD. Then the front and rear seals both took a crap at the same time, which I still dont understand. I had to check the oil level every day, as it would leak alot. I didn't have time to pull it, as the truck was my dd and I went to school and work 6 days out of 7. One day I topped it off, left for school, and right as I got there I heard this nasty clanking. Yup, all the gear oil had pissed out of it. After that you could tell I had hurt some of the bearings, as it was even noisier than before (btw, the NP205 is about the same noise wise). It lasted for maybe a week, then on my way home from work (after topping it off yet again, I was carrying 6-7 quarts of gear oil with me at this point, as well as a large piece of cardboard to lay on under the truck), it locked up when I was going 55 mph. Not fun. I took it out of the truck and took the pto cover off, and there was a few drops of gear oil left in it. The gear oil that was left was silver in color, and about 2/3 of the case's bearing balls were in the bottom. The gears dont look damaged but I have no clue why it locked up. Then I called up Meritor (who makes the parts for Rockwell tcases now, as well as brakes and axles for big trucks) and prices are just hideous compared to the 205. The choice was easy for me. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

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