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Old 09-20-2024, 03:05 PM   #1
Short 3/4
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Join Date: Jan 2017
Location: Los Osos Ca
Posts: 555
Assessing two T221 cases

I need to reseal my leaky T221 transfer case that I had completely rebuilt in the past using the parts from a couple different cases plus some parts off of eBay. It works okay, other than of course being very loud (probably not helped by the mismatched gears). A few years after I rebuilt it I came across another case from what looked to be a very original truck being parted out. I had high hopes for this case, as the transmission out of the same truck was one of the tightest SM420’s I’ve ever driven. I installed the new case long enough to verify it worked, then removed it and put it on the shelf as a spare.

I’m now in the process of deciding which case to put some time and money into. In the pictures the previously rebuilt case is the one marked 65. The newer to me one is marked 66.

My initial assessment shows both having slop in the input shaft. One is about 1/8” while the other is around 3/32”. What is considered acceptable? There is side to side movement of the gears on the counter shaft. One is .010” and the other is .030”. What is considered acceptable, and how is it adjusted? It also appears the gear on the 66 countershaft is installed backwards. What other things should I be looking at? The gears in both cases look to be in good condition.

Of course any discussion of 221 cases is not complete without asking about parts sources. I know seals and bearings are easy, but how about hard parts. Any companies or members parting out cases?

Thanks for any help and advice
Tom
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65 short stepside K10
292-SM420-T221
8 lug closed D44 front
NoSpin HO72 4.10 rear

Last edited by Short 3/4; 09-20-2024 at 07:35 PM.
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Old 09-20-2024, 03:25 PM   #2
Short 3/4
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Re: Assessing two T221 cases

Here’s the pictures
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65 short stepside K10
292-SM420-T221
8 lug closed D44 front
NoSpin HO72 4.10 rear
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Old 10-10-2024, 03:23 PM   #3
Short 3/4
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Join Date: Jan 2017
Location: Los Osos Ca
Posts: 555
Re: Assessing two T221 cases

Still looking for some advice on this.

Is my assumption that the small gear on the 66 case idler shaft is installed backwards correct?

Looks like shims on the counter shaft is for movement of the shaft itself, and not movement of the gears on the shaft. Would shimming at the spacer between the gears to reduce gap be helpful?

I’m having a hard time removing the counter shaft on the 66 case. As I understand it the shaft should be able to be taped out from inside the gears. Both end caps are removed, but even with a steering wheel puller bolted to the 3 holes on the case, I can’t get the shaft to move from either direction. How do I get that thing out of there?

Have been researching past posts on this and other forums, but can’t find the answers to these questions…help!

Thanks for any advice
Tom
__________________
65 short stepside K10
292-SM420-T221
8 lug closed D44 front
NoSpin HO72 4.10 rear
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