I want to install a Lockrite locker in my 89 Sidekick 2dr.  A friend of mine told me to order the #1510 locker.  Is this the one I should order?  If not, which one?  Thanks,  John

Yes, a 1510 will work in your sidekick.  It is the type that reuses the stock sidegears.  You will also have to reuse your crosspins (not a big deal), since the ones that will come with the locker will not have holes drilled in them for the roll pins (because the locker is actually made for a samurai).