When to Replace a Transmission: Age vs Mileage Data
Owners buy reman transmissions at median 153k miles and ~11 years old—but age and mileage correlate weakly (r≈0.24). See claim and purchase patterns.
Quick Answer
Transmission buyers in this dataset typically order at **153,532 miles** and **11 years** of vehicle age — but **age and odometer correlate weakly** (*r* ≈ 0.24). A 12-year-old truck may show 120k or 220k miles. Use **both** numbers plus symptoms, not mileage alone.
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What Does This Article Cover?
- How **age and mileage** relate at time of transmission purchase - **Median purchase mileage** (~153k) and median vehicle age (~11 yr) - Why **weak correlation** means neither number alone decides timing - **Claim-rate patterns** by purchase-mileage band - When to shop earlier and what to document after install ## What Does Age vs Mileage Data Show for Transmission Buyers?
| Metric | Transmission orders | |--------|---------------------| | Sales with odometer | **24,470** | | **Median purchase mileage** | **153,532 mi** | | **Median vehicle age at purchase** | **11 years** | | Age ↔ mileage correlation | **r ≈ 0.24** (weak) |
**Plain-language takeaway:** There is no single “right” year or mile — compare to body type: /blog/suv-vs-truck-transmission-replacement-mileage and model year cohort: /blog/transmission-replacement-mileage-by-model-year.
How Do Claims Relate to Purchase Mileage?
| Purchase-mileage band | Matched claim rate (approx.) | |-----------------------|------------------------------| | Under 80,000 mi | **10.0%** | | 80k–249k (middle bands) | ~11–13% | | **250,000 mi and above** | **14.8%** |
Sample size for high-mileage band analysis: **n = 2,421** matched orders in export cross-ref.
Most warranty reviews in the **first 500 miles** still trace to **install setup** — see drivetrain claims in the first 500 miles: /blog/drivetrain-claims-first-500-miles-after-install. Full mileage hub: at what mileage do customers replace a transmission: /blog/at-what-mileage-do-customers-replace-a-transmission.
When Should You Replace Earlier Than the Median?
| Situation | Action | |-----------|--------| | Harsh shift or slip well below 120k | Scan · check fluid · document before ordering | | Tow / commercial / plow use | Plan cooler and fluid service · monitor shudder | | Burnt fluid or metal in pan | Replacement may beat repeated repair | | Repeat service with no improvement | Confirm internal wear vs software |
About **14%** of all transmission orders were **under 100,000 miles** — valid when failure is confirmed, not on a single code alone.
Before You Buy a Reman Transmission: Checklist
| Step | Action | |------|--------| | 1 | Confirm **transmission application** matches **VIN and build codes** | | 2 | Record **odometer photo** for warranty activation | | 3 | Plan **fluid, filter, and cooler line** service with install | | 4 | Verify whether **TCM relearn / reflash** is required for your build | | 5 | Activate coverage within the required window — activation timing: /blog/reman-transmission-activation-windows-warranty-timing | | 6 | Retain **install invoice** and shop details |
Compare expectations: used vs reman before purchase: /blog/used-vs-reman-expectations-before-purchase
What Should You Document If Problems Start Soon After Install?
Many transmission warranty reviews involve the **first 500 miles** after install — often fluid, cooler flow, seals, or programming — regardless of pre-replacement mileage.
Before any unit is removed under warranty:
- Odometer photos at delivery and at symptom onset
- Scan tool report (stored and pending codes)
- Fluid type, level, and condition notes
- Install invoice with date and shop name
- Photos of leaks **before** cleanup
Full checklist: required documents for a warranty claim: /blog/documents-required-warranty-claim · drivetrain claims in the first 500 miles: /blog/drivetrain-claims-first-500-miles-after-install
> Before any unit is removed or replaced, document the symptom, save scan results or inspection notes, and contact support with the installation details so the issue can be reviewed accurately.
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FAQ
Should I use age or mileage to decide when to replace a transmission?
Use **both**, plus diagnosis. Weak correlation (*r* ≈ 0.24) means a 12-year-old vehicle may have 120k or 220k miles — neither alone predicts your situation.
What is the median mileage for transmission replacement?
Across **24,470 sales**, the **median purchase mileage is about 153,532 miles** at roughly **11 years** of vehicle age.
Do claim rates rise at very high purchase mileage?
Slightly — **250k+ band ~14.8%** vs **under 80k ~10.0%** in matched orders — but early-mileage reviews often involve install setup, not wear alone.
Where is the full transmission mileage hub?
See at what mileage do customers replace a transmission: /blog/at-what-mileage-do-customers-replace-a-transmission (P-A6) for percentiles by body style and model year.
What should I document if problems start soon after install?
Odometer photos, scan report, fluid notes, and install invoice — see required documents for a warranty claim: /blog/documents-required-warranty-claim and 0–500 mile claims hub: /blog/drivetrain-claims-first-500-miles-after-install.
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Related on Expedia Parts
- Warranty policy and Expedia Protection: /warranty
- Warranty activation — 14-day rule: /blog/warranty-activation-14-day-rule
- Documents required for a warranty claim: /blog/documents-required-warranty-claim
- Reman transmission won’t shift after install: /blog/reman-transmission-wont-shift-after-install
- When your transmission needs a reflash: /blog/when-transmission-needs-reflash
- Engine won’t start after install: /blog/engine-wont-start-after-install