The present invention is directed to the incorporation of functionalized polyethylenes, in amount of about 1% to 95% by weight based upon the weight of the total crosslinkable material, into ethylene alpha olefin elastomers, such as EPDM elastomer compositions, which are crosslinked by peroxides, which results in improved properties, such as hardness and modulus of elongation, and can result in improved higher abrasion resistance, wear resistance, coefficient of friction, tensile strength, and other properties through a broad temperature range, which are beneficial to power transmission products, such as power transmission belts.