thatguywv

I am a fan of Amsoil Trick Shift transmission fluid. I run it in my 06 Dodge Ram, after I had a full billet transmission installed. The 48re call for atf4+ and I have not had any problems running synthetic in it. BTW my truck dyno'ed 870ft-lbs. The guy who rebuilt my transmission uses it in his sledpull truck which is pushing about 1800ft-lbs also.

Snap-Off

I see what you mean, but just reiterating that stock ATF+4 is synthetic ATF.

I don't know anything about Amsoil fluid to start off. But if your transmission builder recommended it then my best guess is that the servos and solenoids in your tranny definitely need something for a firmer, more solid shift with all that power infront of it (no good having sloppy shifts with almost 900 ft. lbs. Planetary gear sets don't like that (or too tight for arguments sake). Either way, the stock tranny will probably run fine on royal purple, amsoil, etc... but as far as stock tranny warranty, tolerances, and like I said earlier the bands being born soaked in that stuff its probably better to just leave it until your warranty runs out to start tinkering with other fluid types. Just my opinion