On the Collar Nut I used a Cain Pipe Wrench to Loosen it and a Big Channel Locks to counter Hold.

I guess I could have used the Chain Wrench to tighten it but I bought a large Combination Wrench with the Intention of cutting it in half but did not have the heart to do that.

When installing snug the Collar Nut down by hand and put the Car on the Wheels and in Neutral and roll the Car Back and forth (if needed have someone inside to brake).
That centers the Drive Shaft before you tighten it.

I was barly able to squeeze under the Car and have enough room to tighten the Collar Nut with the Big Combination Wrench an I didn not counter hold the Shaft.

There is a specific Torque on the Collar Nut but I have not read of anyone using a Torque Wrench on it.

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84 300D, 82 Volvo 244Gl Diesel