What is the lightest/best cold flowing ATF?

[Rallywagon]

I just went through the common ATF's to choose for a flush and refill of my VW Eurovan PS system. I went with the Castrol ATF+4 because it has good low temp viscosity, high VI and was readily available. I was afraid the very thin Dexron VI fluids might be too thin for my high mileage 1993 model. Here is a list sorted by 40C KV...

Brand Version KV 100C KV 40C VI
Valvoline MaxLife Dex/Merc 6.11 28.8 173
Valvoline Dexron-VI 6 29.5 155
Mobil Dexron-VI 5.83 29.5 145
Castrol Dexron VI 6.1 30.2 148
Havoline(Chevron) Synthetic MV Dex-VI 6 30.6 147
Castrol Transmax Dex / Merc 7.2 32 200
Redline C+ 7.5 32.3 213
Royal Purple Max ATF 7.5 32.5 210
Castrol Transmax ATF+4 7.5 33 206
Mobil ATF 3309 7.1 33 181
Motorcraft Mercon V 7.5 33.2 205
Havoline(Chevron) ATF+4 7.51 33.24 204

 

[friendly_jacek]

To answer the OP's question literally, it's Toyota WS. 5.5 cSt @100C and 25 cSt @40C (VI=185). Shears down 10-20% quickly too.

 

[moss]

As far as I know the thinnest ATF is Shell 134-FE which is used in the latest Mercedes-Benz transmissions, and meets MB 236.15 specification. Shell 134-FE is blue in color. Viscosity 4.4 cSt @ 100C and 19 cSt @ 40C.

 

[ac_tc]

CHF11 ?