MG · Known Issues

1967 MG MGB Problems: 1 Known Issue

1967 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated August 2026

1967 · All trims · All engines

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All 1 Known Issue

On the 1962-1967 MG MGB 1800 B-series I4, the early MGB four-speed has synchromesh on only the top three gears (none on 1st) — the so-called 'three-synchro' box used through 1967. Its known weak points are the layshaft and its needle rollers (the original three-hole layshaft/laygear design is the fragile part) and the 2nd-gear synchro ring, which wears first and produces the classic crunch when shifting up into 2nd. Worn layshaft bearings give a rumble/whine in the gears and slop in the cluster. Left alone the synchros eventually let go and the box jumps or grinds.

Common Symptoms

Crunch/grind shifting up into 2nd gear
Whine or rumble that changes with gear selected
Jumping out of gear under load
Stiff or notchy shift quality

How to Fix

On a rebuild, the community fix is to upgrade the internals rather than just replace like-for-like: fit the stronger larger 4-hole laygear (22H1301) with a quality layshaft and fresh needle rollers to cure the inherent layshaft weakness, renew the 2nd/3rd/4th synchro rings, and replace all bearings and seals. Done with the right parts, even a three-bearing-laygear box is good for 50,000+ miles. Many restorers go a step further and swap to the later all-synchro four-synchro box (1968-on) for everyday usability, and the most popular bulletproofing upgrade is adding a Laycock overdrive (or a modern 5-speed conversion) to drop cruising rpm and reduce strain. Drive sympathetically with a brief pause into 2nd to preserve the synchros.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

NOS MGB three-synchro four-bearing laygear 22H1301
OEMBMC / MG 22H1301
1965-1967 late four-bearing three-synchro laygear branch after gearbox identity and wear are confirmed Fitment/availability: The inspected direct U.S.
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Typical repair cost:$600 - $2,500

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Community Reported

High ConfidenceVerifiedReviewed Jun 2026

Frequently Asked Questions

What are the most common MG MGB problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1967 MG MGB has 1 documented issue. The documented issue is: Weak Three-Synchro Gearbox — 2nd-Gear Crunch and Layshaft Wear. None are rated critical, but regular maintenance is recommended.

Is the MG MGB reliable?

The 1967 MG MGB has 1 known issue compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. None of the matching records is rated critical; this is not a complete reliability assessment. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common MG MGB problems?

Repair costs for known MG MGB issues range from $600 to $2,500, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1962-1967 MG MGB Weak Three-Synchro Gearbox — 2nd-Gear Crunch and Layshaft Wear?

The early MGB four-speed has synchromesh on only the top three gears (none on 1st) — the so-called 'three-synchro' box used through 1967. Its known weak points are the layshaft and its needle rollers (the original three-hole layshaft/laygear design is the fragile part) and the 2n… Repairs typically run $600-$2,500. Severity: medium.