Exact same thing as the Pennzoil. Read the label if you run across it sometime, it's specifically made for GM vehicles with brass or soft-metal synchros and lists a bunch of GM specs it meets. Only difference is you don't get raped on the price.What works well is GM synchromesh found at any Gm dealer.
It was recommended to me by Pharmecis, did it about 15k ago.but that is gl-5
I use the BG Syncromesh and has been very pleased. Shift transitions seemed smooter after I changed it (from whatever the dealer had used). However, this will be my 1st winter using it so I'm not sure how the cold will affect it.I was planning on changing to BG Syncromesh from RRE in a few weeks anyway.