Ok,I have decided that I am going to order a locker for my 265.Having checked most of the feedback,I have settled on the truetrac.These apparently split at 3.54 and down,and 3.73 and up,now I have a 3.54 diff which takes a 912a584 I came across a post on Dave Bartons site,about the 588 fitting in a 3.31,rather better than the "right" part#.Before I order which should I go with?While checking out pricing,the 584 is not listed as a rear option,does this mean that it is not high preload,like the 588?What other stuff should be replaced at the same time?,Any help would be appreciated.

The Volvo diff takes the same unit, regardless of ratio. I believe it's the 588. The post on Dave Barton's site might've been from Matt as he tried the other diff in a 3.31 and it didn't fit.

the 588 is the new part number. It used to be the 411 part number, apparently the 588 one is stronger, 3 gear instead of 2...something like that. Both are still high pre-load.

The 584 one didn't have the correct spacing if I remember right.