I came across this old thread doing research and I am not here to "stir it up" but I just wanted to clarify/update it in case anyone came across it.
The Redline equivalent of Shell m1375.4 is Redline D6 ATF based on Redline Application Guide.
I used Redline Application Guide which advised Redline D6 ATF. In simple terms:
Shell m1375.4 = MerconŽSP = D6 ATF
Esotar the originator of this thread choose the incorrect Redline (D4) equivalent for Shell m1375.4 (I do not know if Redline D6 ATF was available at the time in 2011)
ARH_0700 tried the incorrect product - Redline D4 which would explain why it did not perform well. (D6 may not have been available at the time)
I have used Redline products with no issue and very pleased with their performance. I would recommend them. I did not want anyone thinking that Redline (or any other "Non-OEM" for that matter) was bad/inferior because the wrong product was selected/choose for the application.
"Everyone is entitled to their own opinions, but they are not entitled to their own facts......."
A helpful thread:http://forums.audiworld.com/archive/index.php/t-2778513.html
From Turkeybaster115 in the above thread:
I did a lot of research as to what in the world our mystery factory fill ATF could be, and I think I finally found it. After a lot of searching, and phone calls to shell USA I have deduced the following:
According to the australian petrolium institute: http://www.lubeandtune.com.au/html/lubekey.asp
their ASP15 classification includes the following fluids:
-Ford Specification No. M2C 919D
-Mercon SP Fluid Part No. XT-6QSP
-Shell ATF M-1375.4
-ZF 6-speed Automatic Transmission Fluid, (Shell M-1375.4)
Mercon SP Fluid is a newer transmission fluid made by shell for Ford dealers. Its easy to find online, and it retails for around $4:00+/quart. Things get really interesting when you look at the specs of lifeguard 6 found in the MSDS:http://www.tsgparts.net/images/pdf/Lifeguardfluid6.pdf
and compare them to the specs of Mercon SP:http://www.fcsdchemicalsandlubricants.co...MERCON%20SP.pdf
VERY similar specs, and the same color fluid.
You can get the lifeguard6/Shell M-1375.4 fluid for $4.68/quart here: http://www.ryderfleetproducts.com/cgi-bin/ryderfp/products/srm/oid/146491/erm/product_detail.jsp
Before you get this fluid consider the following; which are my opinions, drawn from online research. Shell was tapped by ZF/Ford, to make this fluid for maximum fuel efficiency. it has very similar specs to amsoil's fuel efficiency transmission fluid:http://www.amsoil.com/storefront/atl.aspx
(Scroll to the bottom of the page).
If you are in/out of warranty, want to change your ATF fluid, with oem, for considerably less than what the dealer will charge, then get the mecron SP stuff. Now for those who have higher torque vehicles with the 6hp19/26 transmissions, you might want to opt for a fluid that will trade you gas mileage for decreased fluid temps. This is especially true if you plan on occasional racing, or power increasing modifications. If you look at amsoil, and redline, you find that they each offer a line of racing/high temp fluid products. These products offer better thermal protection for racing or high torque vehicles. Looking closely, there're specs differ from the fuel efficient lines. Most notebly: KV @ 40C 7.5-10cst; KV @ 100C 34-53cst VI: 177+, Flash point 225 F+. Clearly the higher the fluid's KV/VI/Flash point, the more sheer stable it is under abnormal stress.
The above listed racing fluids are on the high end. You can have slightly more thermal protection than stock with several other fluids(KV 40C: 7-8, KV 100C 34-38, VI 165+, Flash Point 212 C+:
-Castrol multi-vehicle atf TE ML 11A
-Pentosin ATF 1 TE ML 11B
-castrol transmax TE ML 11B, 14C!
None TE ML optoins include:
-amsoil universal atf
-valvoline max life
-royal purple max gear