seeking input on synthetic atf tranny fluid . What do you think amsoil vs royal purple and your reasons and experance thanks for your input.

 

On paper and in theory the amsoil performs better. However in practicallity i can only tell you about the amsoil. I run the amsoil atf in my 04.5 and i could tell the difference from regular trans fliud i have not tried the purple stuff but it is also supposed to be a great product.

 

You should only use synthetic ATF+ 4 fluid. Mopar at Wal Mart is fine.....4.64 a quart last time I bought it.

 

From the various bits I've read the type IV synthetic base stock that Amsoil is made from compared to the type V that RP is made from is better for extended drain periods. For short term racing with short drain periods RP would be a (slightly) better choice, IMHO.

Opinions are just like any other body orifice so maybe it's whatever you want to afford...

 

I don't know about atf but I've had better luck with RP products than Ams. My 5600 synchros don't like Ams as good as RP and I have better UOAs with RP Maxgear than Ams. My 4500 liked Ams better than RP. After 20+ years of doing UOAs, I swear every machine is different. Flip a coin! I probably wouldn't pass up Mopar atf at Walmart for 4.64 either. I think when it comes to the boxes, you can go by looks (color) , smell, metal on the magnets and gut feeling and skip the UOAs. Craig

 

I have changed my RP twice in my tranny, and it always looked good. Seems to work great.....for me.

 

Wal mart ATF +4 is NOT a Group 4 synthetic.Nor is Mopar ATF+4

 

I don't know about Wal Mart brand. I never said Mopar is a Group 4 synthetic. However it does state it is fully synthetic ( as classified by the Supream Court. It is made from Very high VI base stock. It is recommended by Chrysler for our trannys.

 

Mopar brand is a group three SEMI SYNTHETIC.So is Wal Mart brand.Like Castrol Syntic oil.Its a Group three.Its just the wording.To me its false advertising but hey the courts said they can use the WORD synthetic.Group three is just a little better refined.Only TRUE synthetics in many peoples books are Group 4s which is the real deal.ATF+4 only difference over the older Atf is slightly different formula to stop torque converter shudder on lockup.You can buy a 9 ounce bottle of additive for Dexron 3 to do the same thing.www.bobistheoilguy.com for the real scoop in fluids and tons of boring reading.

 

Mopar may not be FULL synthetic BUT Amsoil isn't ATF+4 so question is which is better.....
When Dodge says to use ATF+4 I'm sure there is a reason;they didn't just pull those specs out of thin air.

 

Amsoil ATF+4 meets and or exceeds Chrysler specs. The reason it was Atf+4 is marketing.. As I mentioned you can use Dexron 3 with some Lubeguard additive and it meets +4 specs.Apparently not a hard spec to meet.

 

I used RPS in my trany and it was good...better than oem fluid, but I like the Amsoil ATF the best. Best shifting and performance I have found.
I also use the same filters as you and I'm not changing. Need to change my sig....

 

Mobil 1 and forget about it..

 

Naw not Mobil 1. Theres better stuff out there.

 

I really don't think there will be many who have used RP and Amsoil in the same tranny for a long enough timeframe to compare the two well.

That said, and I am not an Amsoil cheerleader-- buy what makes you happy-- I have used Amsoil ATF for about 30k and am very happy with it. It seems to handle the heat better over time than the Mopar ATF+4.