Diff locker re-visit

Hello all, after reading an old thread on diff lockers for our vans, I done some research on Google and with the mechanics I work with, on the old thread there was concern about trying to lock the centre diff, and that if this could not be done, then trying to put in front and/or rear lockers was a waste of time. I am now able to tell you that on my SC (1993 SC Limited 3ltr 1kz-te Auto) the centre diff is all ways locked, as the centre diff is a chain drive, there is no need to lock it. If for some reason you are not getting a 50/50 split from this, then there is a good chance that your chain could be slipping or broken, or worse yet you could have a broken axle.  

Here is a link to where I get all my part numbers from. This was done up for my chassis number but should hopefully help everyone out. Smile

http://jp-carparts.com/toyota/figlist.php?maker=toyota&type=711140&cartype=144

I do have one question though, can any one tell what type of diff is in the front of our vans? is it the same centre as the back diff? or is the ADD from the IFS Surf? what they mean by ADD I have no clue.