i'm pretty sure i'm going to switch my whole driveline and engine to amsoil . amsoil said to run 5 /30 in my truck with the mods i have listed in my sig but i talked to a amsoil dealer and he said to run 15/40. i agree with what he is saying but whats everybody else running are ther any disadvantages to running this i'll be going into a cold illinois winter soon and was want better starting i was running rotella t with 2 qts of lucas one day it was really cold and for about 10sec i didn't have oil pressure i don't want that again. will this make my trans shift any smoother cause ever since i installed a bd shoft shift it been a hard shifter.

 

15/40 synthetic will flow nearly as good cold as it will hot. I doubt it will make much difference in your tranny. The short shifter gives you less leverage to move stuff around in the tranny ergo the hard shifting.

 

I run amsoil in everything but my motor. I still run nothin but Delo in the motor. I have been thinking about running amsoil in the motor but it is hard to turn away from something that works so good. I also have some shifting difficulties with the short throw. It is directly related to the shifter leverage if you have been running the correct oil. But anyways i am really happy with the amsoil and am going to continue to run it.

 

I run Amsoil in absolutely everything that takes oil. My wifes Subaru, My Harley, My Dodge/Cummins, My 82 Mercedes diesel, even lawnmowers and weed whips. There are probably plenty of other oils out there that are good, but like you said why switch from something "I know works". You will be in awe of the cold weather starts. It will spin over so fast and start, it will probably scare you at first.

 

I would stay with the recommended tranny fluid in a manual either Mopar or GM lube.
In Illinois, I would stay with 15w-40 in the engine. The 5W-30 is fantastic for winter, but I was disappointed in the amount of breather misting in the summer.

 

I have never used amsoil in my truck or any thing for that matter, and the reson being: I race motocross, and i have heard more people have problems with amsoil, mostly that is doesent protect very well under stressful hot conditions in four-stroke motors, and in 2 stroke motors, is has horrible ash build up in your exhaust ports.
Just my 2-cents.....

 

My experience has been just the opposite.

 

i've heard its one of the best oils to use in the nv4500 and i've been planning to change my tranny oil with amsoil i just havn't gotten around to it yet.

 

Or maybe the guys that run it don't want their competition to run it so the steer them in another direction?