Automatic transmission and wet brake fluids and additive package therefor

In an oil-based functional fluid composition formulated for use as an automatic transmission fluid, the improvement pursuant to which said composition contains a minor amount of at least the following components:

• a) one or more oil soluble phosphorus-containing additives and/or Phosphorus-and boron-containing additives in an amount sufficient to provide in said fluid composition a phosphorus content in the range of 50 to 500 ppm and b) one or more polyols selected from the group consisting of ethylene glycol, 1.3-propylene glycol, 1,4-butylene glycol, trimethylolpropane, pentaerythritol, 2-butene-1.4-diol, cyclohexanedimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule;
• said composition providing a dynamic coefficient of friction within the range of about 0.12 to about 0.17.

In an additive concentrate formulated for use in the production of an oil-based automatic transmission fluid, said concentrate comprising one or more diluents or solvents in an amount that does not exceed 50 percent by weight with the balance being additive components, the improvement pursuant to which said concentrate contains a minor amount of one or more polyols selected from the group consisting of ethyleneglycol, 1,3-propyleneglycol, 1,4-butyleneglycol, trimethylolpropane, pentaerythritol, 2-butene-1,4-diol, cyclohexanedimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule, said polyol having the ability of increasing the dynamic and static coefficient of friction of a friction surface within an automatic transmission in contact with at least mineral oil-based transmission fluid containing said concentrate at a concentration such that said fluid contains an amount of said polyol in the range of 0.01 to 0.5 weight percent based on the total weight of the automatic transmission fluid.

A method of increasing the dynamic coefficient of friction between frictional surfaces contacted by a functional fluid suitable for use as an automatic transmission fluid, a fluid for a wet brake system, or a friction-depending lubricant, which method comprises blending with said functional fluid one or more polyols selected from the group consisting of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, trimethylolpropane, pentaerythritol, 2-butene-1,4-diol, cyclohexane-dimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule in an amount that does not exceed about 0.5 percent by weight based on the total weight of the fluid, said amount being sufficient to increase said dynamic coefficient of friction.

In a low-ash or ashless oil-based functional fluid composition formulated for use as an automatic transmission fluid or a fluid for a wet brake system, the improvement pursuant to which said composition contains a minor amount in the rang of up to about 0 .5 percent by weight based on the total weight of the functional fluid composition of at least one polyol selected from the group consisting of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, trimethylolpropane, pentaerythritol, 2-butene-1,4-diol, cyclohexanedimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule to increase the dynamic and/or static coefficients of friction of the friction surfaces of the automatic transmission or wet brake system contacted by the composition.

In a low-ash or ashless oil-based functional fluid composition formulated for use as an automatic transmission fluid, the improvement pursuant to which said composition contains a minor amount of at least the following components:

• a) one or more oil soluble phosphorus-containing additives and/or phosphorus-and boron-containing additives in an amount sufficient to provide in said fluid composition a phosphorus content in the range of 50 to 500 ppm and b) one or more polyols selected from the group consisting of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, trimethylolpropane, pentaerythritol, 2-butene-1,4-diol, cyclohexanedimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule;
• said composition providing a dynamic coefficient of friction within the range of about 0.12 to about 0.17.

In an additive concentrate formulated for use in the production of a low-ash or ashless oil-based automatic transmission fluid, said concentrate comprising one or more diluents or solvents in an amount that does not exceed 50 percent by weight with the balance being additive components, the improvement pursuant to which said concentrate contains a minor amount of one or more polyols selected from the group consisting of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, trimethylolpropane, pentaerythritol, 2-butene-1,4-diol, cyclohexanedimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule, said polyol having the ability of increasing the dynamic and static coefficient of friction of a friction surface within an automatic transmission in contact with at least mineral oil-based transmission fluid containing said concentrate at a concentration such that said fluid contains an amount of said polyol in the range of 0.01 to 0.5 weight percent based on the total weight of the automatic transmission fluid.

A method of increasing the dynamic coefficient of friction between frictional surfaces contacted by a low-ash or ashless functional fluid suitable for use as an automatic transmission fluid, a fluid for a wet brake system, or a friction-depending lubricant, which method comprises blending with said functional fluid one or more polyols selected from the group consisting of ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, trimethylolpropane, pentaerythritol, 2-butene-1,4-diol, cyclohexanedimethanol, and 1,2-alkanediols having from 3 to 6 carbon atoms in the molecule in an amount that does not exceed about 0.5 percent by weight based on the total weight of the fluid, said amount being sufficient to increase said dynamic coefficient of friction.