Knock on startup?

[Michaeljp86]

if the pulley is bad you should be able to rotate it back and forth

Would I have to take the belt off to do that?

 

[MihaiPirvu]

Look at this picture and enlarge it... http://www.autozone.com/autozone/pa.../_/N-j92mbZ93y2h?itemIdentifier=72833_0_8644_ There are 3 pictures there so if you look at the third, the one which look like pictured from front of engine you see like a metal "cross" with four holes in sides for bolts. In my case the inner part off rubber was cracked all around and the bolts which you see their holes pictured equal distanced from the "cross" were touching the "cross". As result I got that "knocking" noise. It is possible that you don't have this type off pulley but if you have it it, is worth checking.

 

[MihaiPirvu]

You don't have to take the belt off, just look from under the truck at it. If you like to try to rotate it, (probably will be better) yes you take the belt off.

 

[Brooklyn Tow]

Look at this picture and enlarge it... http://www.autozone.com/autozone/pa.../_/N-j92mbZ93y2h?itemIdentifier=72833_0_8644_ There are 3 pictures there so if you look at the third, the one which look like pictured from front of engine you see like a metal "cross" with four holes in sides for bolts. In my case the inner part off rubber was cracked all around and the bolts which you see their holes pictured equal distanced from the "cross" were touching the "cross". As result I got that "knocking" noise. It is possible that you don't have this type off pulley but if you have it it, is worth checking.

Like said, make sure the Cross and the bolt holes are centered.....and inspect the rubber for dry rot, cracks, etc.

 

[Michaeljp86]

If the only rubber is the large band of rubber around the inner part of the pulley then I think it looks fine.

 

[DieselCash]

From that pic it looks good and still centered. :thumbsup: