Why Your Reman Transmission Won't Shift After Install
No shift after a reman transmission swap is often fluid level, relearn, or range sensor — not a bad unit. See checks before removal or warranty review.
Quick Answer
When a **reman transmission won't shift after install**, the cause is **often setup-related** — low or wrong ATF, incomplete **TCM relearn or reflash**, range or speed sensor issues, or **limp mode** from stored codes — not immediate proof of internal failure. Verify **fluid level hot**, scan for **P0700-series codes**, complete **OEM relearn steps**, and document results **before** removing the unit or opening a warranty review.
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What Does This Article Cover?
- **Most common causes** of no-shift after a reman swap
- **Step-by-step checks** before assuming a defective unit
- **Diagnosis table** by symptom pattern
- **Before filing a claim** documentation checklist
- When to **contact support** and why pre-authorization matters
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What Are the Most Common Causes?
| Cause | What you may notice | Why it happens after R&R | |-------|---------------------|---------------------------| | **Low / wrong ATF** | No move, harsh clunk into gear | Air in lines, wrong spec, underfill after converter fill | | **Incomplete relearn / reflash** | Stuck in one gear, limp | TCM not adapted to new unit; battery disconnect reset | | **Range or speed sensor** | PRNDL mismatch, no shift | Connector, adjustment, damaged sensor on R&R | | **Stored codes / limp** | MIL on, limited gears | Prior codes not cleared; voltage sag during programming | | **Converter not fully seated** | No move, noise | Install procedure — verify before condemning unit | | **Cooler restriction / no flow** | Overheat + slip/no shift | Debris, reversed lines, blocked cooler |
Related: transmission reprogramming after replacement: /blog/transmission-reprogramming-after-replacement · fluid leaks after replacement: /blog/transmission-fluid-leaks-after-replacement.
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What Should You Check Before Assuming a Bad Unit?
1. **Fluid** — correct spec, full level **hot**, no major leak (photo if leaking) 2. **Scan tool** — save **all** stored and pending codes; note freeze frame 3. **Battery** — stable voltage during relearn (charger recommended) 4. **Relearn / reflash** — complete OEM or supplier procedure for your YMM 5. **Range sensor / linkage** — PRNDL matches dash indicator 6. **Line pressure / manual valve** — shop verification if limp persists 7. **Cooler flow** — verify flow direction and no blockage 8. **Do not remove** the transmission without support guidance — pre-authorization: /blog/pre-authorization-before-removing-unit
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Quick Diagnosis Table
| Symptom pattern | Likely cause | First check | |-----------------|--------------|-------------| | No move in any gear | Fluid level / converter | Hot level, converter fill procedure | | One gear only / limp | Codes, relearn | Full scan + relearn | | Wrong gear indicated | Range sensor, linkage | PRNDL vs selector | | Worked then stopped | Heat, leak, low fluid | Level, cooler, photos | | Tow-in / dead battery | Low voltage, incomplete adapt | Charge + relearn |
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Before Filing a Claim
| Item | Required | |------|----------| | Full scan report (stored + pending) | Yes | | Fluid type and level notes | Yes | | Relearn / programming proof | If applicable | | Odometer + miles since install | Yes | | Install invoice | Yes | | Photos (leaks, wiring) | If applicable |
> 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.
Full list: required documents for a warranty claim: /blog/documents-required-warranty-claim.
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FAQ
Does no shift always mean the reman transmission is defective?
No. Early warranty data shows **fluid, relearn, and sensor** issues drive many no-shift reports in the first **500 miles** — see early failure hub: /blog/reman-transmission-failed-within-500-miles.
Can a scan tool relearn fix no shift?
Often yes when codes point to **adaptation or range**. Complete OEM procedure before removal.
Should the transmission be removed to diagnose no shift?
Not without **pre-authorization** when removal is required — document scans and fluid checks first.
What if I also have slip or shudder?
See transmission slip and shudder after replacement: /blog/transmission-slip-and-shudder-after-replacement — overlap is common.
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P1 · SC-T-NOSHIFT · INV-05 · INV-07 · INV-10 · SME pending · P1 cleanup 2026-06-28
Related on Expedia Parts
- Warranty policy and Expedia Protection: /warranty
- Warranty activation — 14-day rule: /blog/warranty-activation-14-day-rule
- Pre-authorization before removing the unit: /blog/pre-authorization-before-removing-unit
- 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