I assume you mean the circlip that's accessed through the slot in the tail. It holds the output shaft in the proper position. I wouldn't run without it.
You need flat and wide bill circlip/lock-ring pliers and long thin screwdrivers to open and position this kind of snap ring. Open the ring and lift the shaft into position. Using regular pin hole circlip pliers is an exercise in frustration. It can be done but it'll drive you to drink.
Knipex 4510170 are a pricy but excellent tool. If the $40 pricetag doesn't put you off... buy them. You can find similar lock-ring pliers from Proto and others in the $20-$30 range. all of em are cheaper than $$nap-On or MAC or Cornwall or ... They're handy for outer CV joint locking rings and various transmission and transfer case locking rings.
This is Eric at South Main Auto doing an NV261. Same operation to hook the clip in. He starts fighting with it just after 54:15
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8
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