Went to attempt replacing the front shocks on my B 1500, but when trying to remove the top shock shaft nut, I can feel that the whole shaft is turning. I could not see a way to put vice grips on the shaft to hold it, Is there a special tool I need? Or is there another way to hold the shaft while removing the nut?

 

There is a special tool that holds the top part while you use an open end wrench to remove the nut. It sort of works. I've usually had to cut the top nut off. You can also use a nut cracking tool to cut the nut. once you split the nut, the shock will drop out.

 

Here is the tool you need to remove and install the top nut.
https://a.co/d/1icwbPN

 

That's the tool I was talking about. It doesn't work every time but I try it first. It works as often as not.

 

does not show for me

 

Lisle 20400 Universal Shock Absorber Tool

 

I used the Lisle 20400 tool (pictured above) with total success. Worked beautifully.

 

Bought that tool yesterday!

 

I've had my tool since before I bought my house in '86. It doesn't work all the time, especially on metric cars, but it works enough that the new ones are the same as my old one. Mine's just a little worn.

 

When you can get a grip on the shaft (and I know the OP said he couldn't), use cardboard between the visegrips and the shaft...

It gives reasonable traction and protects the shaft at the same time. Rag doesn't cut it in this usage.