What contract, Q? A contract this mindless garble isn't!
A contract is an agreement between parties creating mutual obligations that are enforceable by law.
When the parties attempt to make a contract where promises are exchanged as the consideration, the promises must be mutual in obligation. Without mutuality of obligation, the agreement lacks consideration and no enforceable contract has been created.
For a contract to be legally enforceable, there must be “mutuality of obligation”. This means that both parties must meet their obligations, and consideration represents the commitment the parties make to each other. Example: Shortell v. Evans-Fergusun Corp., 98 Cal App 650, 660-662, etcetera's.
So, where in this discordant mass of purported legalese is there even a hint of "Exeter Finance" incurring any obligation or commitment whatsoever?
Also, notable (if we take as granted OP's narrative of past events) it would appear that "Exeter Finance" exercised its default remedies by repossessing the Dodge vehicle and disposing of it in a reasonable commercial manner. Thus, essentially any money remaining due and owing Exeter Finance would be the loan balance at the time of the repo less what Exeter received by means of disposing of the vehicle. In other words, Exeter's legal position would be of one seeking a deficiency judgment. (The obvious assumption being that OP was upside down so far as the loan being adequately secured.)
Yet nowhere in this "Settlement Letter" is there any reference to Exeter having pursed its default remedies; or the results of exercising its legal remedies; or any efforts or intent on the part of Exeter in seeking a deficiency judgment; OR, importantly Exeter waiving its right to pursue a deficiency judgment against the OP in exchange for his promises therein.
By extrapolating I suppose one could fairly surmise that the figure of $995 as mentioned in the Settlement Letter represents the substance of a deficiency balance. However, in contrast we find this in the body the Letter:
"WHEREAS, as of the date of this Agreement, (post the repo) the current outstanding balance owed to Exeter under the terms of the Contract is $10,000."
How can this document be interpreted to the effect that the OP's payment to Exeter of $995 shall be "in full payment of the amounts due under the contract" (OP's words) when the document recites that the balance due Exeter is $10,000?
This substantive ambiguity and lack of certainly, notwithstanding the absence of mutuality of obligation, alone repudiates any legal significance to the writing. I judge would "86" it on his own motion.
If the OP wants to pay a lawyer to tell him much the same, that is his prerogative. But my suggestion is that he return the document unsigned and request in return a letter from Exeter confirming the true and acceptable amount owed and agreeing to waive its right to seek a deficiency judgment upon payment thereof.