We now have multiple threads, 84+ pages of discussion, and a growing statistics thread documenting front driveshaft CV joint failures across the global Grenadier fleet. What we don't yet have is clean, structured data on **warranty outcomes relative to vehicle configuration**. There also is not a clean denominator to this problem (e.g., a poll with those responding 'No Problem'). If it was just 68 problems out of about ~15K vehicles sold world-wide (just guessing)....thats a very small problem. However, what has me interested is that if the failure is across bone stock and modified vehicles alike at a similar rate there is potentially a
Magnuson-Moss Warranty Act issue if coverage is denied.
I was thinking about starting a new forum thread use the survey poll feature across these 11 response items:
Code:
Poll Question: What best describes your front driveshaft CV joint experience? (Select all that apply)
1. No failure, stock suspension & stock tires
2. No failure, stock suspension + larger tires (33"/34"/35")
3. No failure, lifted suspension
4. No failure, lifted suspension + larger tires (33"/34"/35")
5. Failure — Approved, stock suspension & stock tires
6. Failure — Approved, stock suspension + larger tires (33"/34"/35")
7. Failure — Approved despite lift and/or aftermarket mods
8. Failure — Denied, cited tire size as reason
9. Failure — Denied, cited lift/suspension mods
10. Failure — Denied, no clear reason given
11. Failure — Approved after escalation (dealer → INEOS)
12. Failure — Self-repaired, no warranty claim attempted
13. Failure on 100% stock vehicle (no mods of any kind)
14. Failure + additional driveline damage (T-case, circlip, splines, gearbox)
The existing data (compiled below) shows a clear pattern: CV boot and joint failures are occurring on
both stock and modified vehicles, at similar mileage ranges (7,500–36,000 km / ~4,700–22,000 mi), with the same failure mode, boot tear at the transfer case end leading to grease loss, contamination, and eventual joint failure.
Yet warranty outcomes diverge sharply based on vehicle configuration:
- **Stock suspension + stock tires** → nearly 100% warranty approval
- **Stock suspension + 33" tires** → approved (documented cases)
- **Stock suspension + 35" tires (255/85R17)** → approved (documented cases)
- **Any lift** → near-universal denial or self-repair without attempt
This creates a serious question under consumer protection law. In the U.S., the Magnuson-Moss Warranty Act (15 U.S.C. §§ 2301–2312) establishes that a manufacturer cannot deny a warranty claim based on the presence of an aftermarket part unless the manufacturer can demonstrate that the aftermarket part caused the failure. The burden of proof is on the manufacturer, not the consumer.
If the same CV boot is failing on completely stock vehicles at comparable mileage, the logical conclusion is that the failure is inherent to the component design (boot material, operating angle, or both), not caused by a 30–50mm lift or a change in tire size alone.
**Total documented failures (de-duplicated):** 31 unique cases across 12 threads (7 new since initial scrape; 1 duplicate removed during audit)
**Note:** HeavyFoot's running tally referenced ~68 entries on the poll thread by Dec 2025; Brad@SuperiorCO's analysis estimated 1.5–3% failure rate for moderately lifted vehicles across forum + Facebook data.
By Suspension Configuration:
| Config | Count | Avg Mileage at Failure | Warranty Approval Rate |
|--------|-------|----------------------|----------------------|
| Stock suspension + stock tires | 14 | ~15,400 mi / 24,800 km | ~79% (11/14 approved; 2 pending; 1 unknown) |
| Stock suspension + larger tires (33–35") | 2 | ~13,750 mi | 100% (2/2 approved) |
| Lifted (any amount) | 14 | ~18,100 mi / 29,100 km | ~14% (2/14; both Australia via Eibach dealer installs) |
| Unknown configuration | 1 | — | — |
By Failure Type:
| Type | Count |
|------|-------|
| Boot tear/rip at T-case end | 21 |
| Complete CV joint failure (circlip/spline/shaft snap) | 5 |
| Boot leak / grease weep (pre-failure) | 2 |
| T-case internal failure (related) | 1 |
| Unclear / insufficient detail | 2 |
By Geography:
| Region | Count |
|--------|-------|
| USA | 18 |
| Australia | 7 |
| UK | 4 |
| Canada | 1 |
| Germany | 1 |
| — | — |
| Warm/no-salt climates | ~16 |
| Cold/salt climates | ~8 |
By Vehicle Type:
| Model | Count |
|-------|-------|
| Station Wagon (SW) | 29 |
| Quartermaster (QM) | 2 (Siddo, Swampy888) |
Code:
**Reference threads:**
- [Front Drive Shaft Update (84+ pages)](https://www.theineosforum.com/threads/front-drive-shaft-update.12418127/) — Main technical discussion
- [Statistics/Poll Thread: Front driveshaft CV joint failures (6 pages)](https://www.theineosforum.com/threads/statistics-poll-thread-front-driveshaft-cv-joint-failures.12420239/) — HeavyFoot's data collection thread
- [Houston, we have a problem. It's the CV boot.](https://www.theineosforum.com/threads/houston-we-have-a-problem-its-the-cv-boot-mossy-houston-update.12418721/) — GN4HIR's warranty experience at Mossy Houston
- [Front drive shaft spitting grease](https://www.theineosforum.com/threads/front-drive-shaft-spitting-grease.12421344/) — jvkintheusa's micro-tear discovery
- [Front drive shaft broken (40 pages)](https://www.theineosforum.com/threads/front-drive-shaft-broken.12414695/) — Oldest thread on issue (Feb 2024); circlip failures, stock failures, earliest cases
- [Front prop shaft snapped](https://www.theineosforum.com/threads/front-prop-shaft-snapped.12419982/) — Roy Panton's stock vehicle failure; NHTSA filing discussion
- [Americas - Front Driveshaft CV redesign (13 pages)](https://www.theineosforum.com/threads/front-driveshaft-cv-redesign.12419230/) — Official INEOS response via Stu_Barnes; engineering acknowledgment
- [Front axle CV failure with warranty coverage](https://www.theineosforum.com/threads/front-axle-cv-failure-with-warranty-coverage.12420707/) — Australian warranty precedent (lifted vehicle covered)
- [Front Drive Shaft Repair Day](https://www.theineosforum.com/threads/front-drive-shaft-repair-day.12419684/) — DIY TeraFlex install documentation
- [Front Drive Shaft - Replacement Cost?](https://www.theineosforum.com/threads/front-drive-shaft-replacement-cost.12420562/) — Pricing data ($1,002–$1,350 USD)
- [Quartermaster Failed Driveshaft - Be Aware](https://www.theineosforum.com/threads/quartermaster-failed-driveshaft-be-aware.12417470/) — First documented QM failure; dealer complicity argument
- [Dual double cardan joint 1350 front driveshaft discussion](https://www.theineosforum.com/threads/dual-double-cardan-joint-1350-front-driveshaft-and-factory-cv-discussion.12416381/) — Technical deep-dive; lateral offset, installation method