Switched to Amsoil today.

[BumblingB]

About 8 years ago I had a F-350 dually diesel. Swapped the tranny fluid in the crud AOD tranny to Amsoil - it was the BEST thing I ever did to that truck. Shifted noticeable smoother and those trannies might as well have been made of glass as they didn't have a good track record behind the diesels. I only drove it another 10k before Sept 11 hit and parking spots were a premium where I worked - finding a spot where I wouldn't get a ding became an ordeal. On Sept 17 I traded it for a SUV. Never saw how long the tranny fluid would of helped.

[zpiloto]

Originally Posted by lindermant

I did an A/B comparison with Havoline 5w20 and RLI BioSYN 0w20 in my 2005 Civic. Both oils run for 5k miles and a used oil analysis (UOA) run on each oil. Looking at my MPG numbers, there was a bit of a drop during the synthetic run, but I was averaging 10+ MPH faster during my commute over that 5k miles...

if you're interested in the resulting wear numbers you can read more here

I'm still learning the numbers from the UOA. How do you determine the OCI? It's looks like you could have gone quite a bit more before you would need to change it.

[lindermant]

Originally Posted by zpiloto

I'm still learning the numbers from the UOA. How do you determine the OCI? It's looks like you could have gone quite a bit more before you would need to change it.

The owners manual lists recommended OCI's; in my case 10k miles for normal service and 5k miles for severe service. I have previously run several 10k OCI's using (non-synthetic) Havoline with decent results.

I ran the A/B comparison of Havo to RLI BioSYN at only 5k cause it took less time to run up the miles And you're right, the RLI BioSYN would easily survive a 10k run.

Here are some results from a Prius owner using RLI and Mobil1...