69 Pa. Stat. § 627
If the proceeds of the resale mentioned in section twenty-six above are not sufficient to defray the expenses thereof, the expenses of retaking and storing the motor vehicle to which the seller or holder may be entitled and the net balance due upon the contract, plus the amount of any accrued default charges authorized by this act, the seller or holder may recover the deficiency from the buyer or from any one who has succeeded to the obligations of the buyer: Provided, That the buyer may have the reasonable value of the motor vehicle at the time of resale, determined in any action or proceeding brought by the seller or holder to recover the deficiency, the resale price being prima facie, but not conclusive evidence, of such reasonable value and the said reasonable value, as determined, or the resale price, whichever shall be higher, shall be credited to the buyer on account of his indebtedness. In every action or proceeding for a deficiency the buyer may have the reasonableness of the expense of retaking and storing the motor vehicle determined. Nothing contained in this section shall apply to a deficiency on a resale which was held prior to the effective date of this act.
69 P.S. § 627