{"product_id":"mercury-mercruiser-transmission-temperature-switch-88031","title":"Mercury MerCruiser Transmission Temperature Switch Assembly 88031 | OEM 87-88031","description":"\u003ch2\u003eMercury MerCruiser Transmission Temperature Switch Assembly 88031\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e 88031 | 87-88031\u003cbr\u003e\n\u003cstrong\u003eSupersedes:\u003c\/strong\u003e 813708 | 87-813708\u003cbr\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Mercury Marine \/ MerCruiser \/ Quicksilver\u003cbr\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Transmission oil temperature switch assembly — OEM\u003cbr\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Marine transmission \/ propulsion electrical\u003cbr\u003e\n\u003cstrong\u003eGTIN \/ UPC:\u003c\/strong\u003e 745061202955\u003c\/p\u003e\n\n\u003cp\u003eThe Mercury MerCruiser 88031 \/ 87-88031 is a genuine OEM \u003cstrong\u003etransmission oil temperature switch assembly\u003c\/strong\u003e used in selected MerCruiser inboard and diesel propulsion packages. It installs directly in the marine transmission and monitors transmission oil temperature for the warning or monitoring circuit. Part 88031 is the current OEM replacement for the earlier \u003cstrong\u003e813708 \/ 87-813708\u003c\/strong\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eCompatible Applications\u003c\/h3\u003e\n\u003cp\u003eShown in multiple MerCruiser marine transmission diagrams — \u003cstrong\u003econfirm part 88031 \/ 87-88031 in your transmission diagram before ordering:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eVelvet Drive 71C\u003c\/li\u003e\n\u003cli\u003eVelvet Drive 72C\u003c\/li\u003e\n\u003cli\u003eHurth transmission installations\u003c\/li\u003e\n\u003cli\u003e45C\u003c\/li\u003e\n\u003cli\u003e45C DTS\u003c\/li\u003e\n\u003cli\u003e45IV\u003c\/li\u003e\n\u003cli\u003eSelected MerCruiser MIE gasoline and diesel propulsion packages\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eLegacy engine applications covered via supersession from 813708 include selected:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e5.7L MIE \/ GM 350 V8\u003c\/li\u003e\n\u003cli\u003e7.4L MIE \/ GM 454 V8 \u0026amp; 7.4L MPI MIE\u003c\/li\u003e\n\u003cli\u003e8.2L MIE \/ GM 502 V8 \u0026amp; 8.2L MPI MIE\u003c\/li\u003e\n\u003cli\u003e350 MAG MPI MIE | 454 MAG MPI Horizon\u003c\/li\u003e\n\u003cli\u003eMerCruiser VM 3.0L \/ 183 CID diesel\u003c\/li\u003e\n\u003cli\u003eMerCruiser VM 3.6L \/ 219 CID diesel\u003c\/li\u003e\n\u003cli\u003eD254 Turbo AC\u003c\/li\u003e\n\u003cli\u003e7.3L diesel applications where the original diagram specifies 813708 or 88031\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSerial Number \u0026amp; Diagram Fitment Notice\u003c\/h3\u003e\n\u003cp\u003eFitment is determined by \u003cstrong\u003etransmission model and propulsion package\u003c\/strong\u003e, not engine displacement alone. Always confirm part 88031 \/ 87-88031 in the transmission-specific Mercury parts diagram for your serial number range before ordering. If you are unsure, provide your MerCruiser engine and transmission serial numbers for fitment assistance.\u003c\/p\u003e\n\n\u003ch3\u003eWhen to Replace\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eA transmission over-temperature warning is occurring without confirmed overheating\u003c\/li\u003e\n\u003cli\u003eThe warning circuit fails to respond during diagnostic testing\u003c\/li\u003e\n\u003cli\u003eSwitch has damaged or corroded electrical terminals\u003c\/li\u003e\n\u003cli\u003eOil leakage is present at the switch installation point\u003c\/li\u003e\n\u003cli\u003eSwitch fails continuity or temperature testing per the service manual\u003c\/li\u003e\n\u003cli\u003eTransmission electrical or warning-system diagnosis identifies the switch as faulty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eA transmission temperature warning does not automatically indicate a failed switch. Verify transmission oil level, oil condition, cooler flow, and actual operating temperature before replacing electrical components.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDisconnect battery power before electrical service\u003c\/li\u003e\n\u003cli\u003eIdentify the correct temperature-switch position in the transmission parts diagram\u003c\/li\u003e\n\u003cli\u003eInspect the electrical terminal and harness connector for corrosion before installation\u003c\/li\u003e\n\u003cli\u003eCheck the surrounding transmission oil system for leakage during the same service\u003c\/li\u003e\n\u003cli\u003eDo not substitute an engine coolant temperature switch — this is a transmission-specific component\u003c\/li\u003e\n\u003cli\u003eFollow the applicable Mercury service manual for switch testing, sealing, and tightening specifications\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSuperseded \u0026amp; Alternate Part Numbers\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e88031\u003c\/strong\u003e — Current Mercury \/ MerCruiser part number\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e87-88031\u003c\/strong\u003e — Full Mercury catalog number\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e813708\u003c\/strong\u003e — Earlier temperature switch (superseded by 88031)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e87-813708\u003c\/strong\u003e — Earlier full Mercury catalog number\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cem\u003eMercury lists 88031 as the current functional replacement for 813708. The replacement may differ visually from the original switch.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eRelated Transmission Components\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131397550116\"\u003eMercury MerCruiser Trim \/ Trailer Switch Assembly 18286T34\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131409543204\"\u003eMercury MerCruiser Quicksilver Switch Assembly 54211T\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131437690916\"\u003eMercury MerCruiser Harness Repair Kit 8M0062017\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical FAQ\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: How do I know if 88031 fits my transmission?\u003c\/strong\u003e\u003cbr\u003e\nLocate part 88031 \/ 87-88031 in the Mercury diagram for your specific transmission model (71C, 72C, Hurth, 45C, 45IV, etc.) and propulsion serial number. The transmission diagram is the correct reference — not the engine diagram.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What replaced 813708?\u003c\/strong\u003e\u003cbr\u003e\nMercury lists 88031 \/ 87-88031 as the current replacement for 813708 \/ 87-813708. The two part numbers are functionally equivalent for the covered applications, though the replacement may differ in appearance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: The over-temperature warning came on — does that mean this switch is bad?\u003c\/strong\u003e\u003cbr\u003e\nNot necessarily. Check transmission oil level, oil condition, and cooler flow first. A genuine overtemperature condition will trigger the same warning as a failed switch. Diagnose the root cause before replacing electrical components.\u003c\/p\u003e\n\n\u003chr\u003e\n\u003ch3\u003eParts Desk Insights\u003c\/h3\u003e\n\u003cp\u003eThe critical detail with 88031 is its location: this is a \u003cstrong\u003emarine transmission temperature switch\u003c\/strong\u003e, not a general engine temperature sender. Mercury uses this switch across several transmission families — Velvet Drive 71C\/72C, Hurth, and 45-series — so the \u003cstrong\u003etransmission diagram\u003c\/strong\u003e is the correct fitment reference, not the engine model alone. The most common ordering mistake is pulling the engine part number rather than the transmission diagram part number, which can result in ordering the wrong sensor entirely. When diagnosing a transmission over-temperature warning, always rule out actual overheating (oil level, cooler flow, operating conditions) before condemning the switch.\u003c\/p\u003e","brand":"MERC","offers":[{"title":"Default Title","offer_id":43563900305444,"sku":"88031","price":171.19,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/6079604f-b55b-49e9-a0c4-05201cea0058.png?v=1787269517","url":"https:\/\/marisolmarine.com\/products\/mercury-mercruiser-transmission-temperature-switch-88031","provider":"Marisol Marine Company","version":"1.0","type":"link"}