They pop up from time to time, when a Riviera is parted out a few have been listed in cars or parts for sale forums and here on the hot air forum, seems that the 3.36 diff was only on the T Type 83 and 84 Riviera. Have not heard of anyone that had an 85 with the 3.36 (from the factory anyway)only the3.15, nor have any idea about the diesel Toronado. A place called Ace Auto Recycling in Arizona had one a few months back, they have sold a few riviera items on ebay, they had an auction for a GN/Riviera digital dash about a week ago, also a place called "The Buick Place" also in arizona ( they have a web site) they may have one left,though I just bought 2 from them @ $175 each plus $50 shipping. I had them and Ace confussed, called Ace by mistake with a quote that The Buick Place gave and the Ace guy said it was a bit more, I found my mistake and called THe Buick Place and bought, anyway the Ace Auto Recycling may still have it.
If either have one great, if not you have to look and ask around, watch for 83-4 T type Riviera's getting parted, it took me awhile, good luck.
