What year is your Tacoma? I had a 99 Tacoma 4wd and it called for a GL-4 gear oil in the transmission and transfer case. The diffs called for a GL-5. I would recommend you try Redline MT-90 Gear Oil for your transmission. There are some more readily available oils that meet both GL-4 and GL-5 specs. However, some have experienced synchro issues after using some of these...if you believe what you read on forums.
www.redlineoil.com/product.aspx?pid=46&pcid=7
