I only know what I've heard, have heard not to mix dino & syn. I had a similar dilema last time I hit a gator. Had switched to AMSOIL synthetic transmission fluid. Gator poked a small hole in the transmission cooler return line. Started having trouble shifting into reverse. Checked the transmission fluid level, two quarts low. Had dropped the trailer so at least running MT. I recalled thinking I should carry a couple quarts of AMSOIL ATF when I switched over, just never got around to getting it. Searched high and low couldn't find any AMSOIL ATF, in fact no SYN ATF of any kind. WalMart didn't have any either. Bunch of RVers overnighting in the lot, I decided to stay and check with them in the morning at first light to see if per chance any of them were using AMSOIL. Ask about 10 of um, every one said "what"? Never even heard of it. Guess it's rare over WV & VA way. Finally hit the road driving around the little burg I was stranded in, came accross a Mobile refinery outlet. They had a SYN but weren't sure if you could blend SYNs. They gave me the phone number of an AMSOIL dealer close by. He had oil, but no transmission fluid. He drove to where I was, then had me follow him for 40 miles of the most fun, twisty turny, rolling hills road I'd ever seen, Route 501. Oh, have to mention, this road angel came in the form of a stroker. We never did find an AMSOIL dealer, but had one hellofa fun drive. Ended up calling ATS, letting them know I needed a transmission fix, they authorized me to take it to some little transmission shop they found on the internet that was close by. 3 hours later I was back on the road to WV for another trailer. But found out you can blend other synthetic transmission fluids with AMSOIL if need arises. But don't think it is the same for motor oils. But if push come to shove I'd say any oil is better than no oil. Best part of my little tale is I had no trouble at all keeping up with the stroker. . . later I found out from my DOC in Angola, IN, Dave's Diesel, that all the while I had been running on 5 cylinders. Had a high pressure injector line had etched through and was blowing fuel all over the rear of the engine. The Saga continues. . .
Cheers,
Steve J.