don't know about synthetic, but I sure wouldn't take a manual trans on the highway that had 30 wt in it!! eek I think I'd trust the manufacturers recommendations rather than yer friend!! grin

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot