What does 6.1.7 mean on an MOT certificate?

It refers to sub-section 6.1.7 of the MOT inspection manual, "Transmission", within section 6, body, structure and attachments. The letter or letters after it — (a), (b)(i) and so on — identify the specific defect from the 13 listed here. 5 of them are graded Dangerous, 7 Major and 1 Minor.

Which transmission defect is recorded most often?

"A transmission shaft bearing excessively worn" (6.1.7 (b)(i)), recorded about 0.0 times per 100 failed MOT tests nationally.

Does a Minor defect fail the MOT?

No. a defect with no significant effect on safety or the environment. Recorded on the certificate; the vehicle passes. Major and Dangerous defects fail. A Dangerous defect also means the car must not be driven until it is repaired.

Section 6 · Body, structure and attachments

6.1.7 Transmission

Manual indexed 3 September 2026

Quick answer

Sub-section 6.1.7 of the MOT inspection manual covers transmission and lists 13 defects, 5 of them Dangerous. A reference like "(6.1.7 (a)(i))" on a certificate points to the matching row below. The most recorded is "A transmission shaft bearing excessively worn", about 0.0 times per 100 failed tests.

Official wording

The defect clauses

6.1.7 (a)(i)Majorunder 0.1 per 100 fails
A transmission shaft securing bolts loose or missing
6.1.7 (a)(ii)Dangerous
A transmission shaft likely to become detached
6.1.7 (b)(i)Majorunder 0.1 per 100 fails
A transmission shaft bearing excessively worn
6.1.7 (b)(ii)Dangerous
A transmission shaft bearing likely to break up
6.1.7 (c)(i)Majorunder 0.1 per 100 fails
A transmission joint, belt or chain excessively worn
6.1.7 (c)(ii)Dangerous
A transmission so worn it is likely to fail
6.1.7 (d)(i)Majorunder 0.1 per 100 fails
A transmission shaft flexible coupling excessively deteriorated
6.1.7 (d)(ii)Dangerous
A transmission shaft flexible coupling so deteriorated it is likely to fail
6.1.7 (e)Major
A transmission shaft bent or badly damaged
6.1.7 (f)(i)Major
A transmission shaft bearing housing fractured or insecure
6.1.7 (f)(ii)Dangerous
A transmission shaft bearing housing likely to fail
6.1.7 (g)(i)Minor
A transmission shaft constant velocity joint boot severely deteriorated
Driveshaft CV joint gaiter split or missing explained: what it means and what puts it right
6.1.7 (g)(ii)Major
A transmission shaft constant velocity joint boot missing, split or insecure so that it no longer prevents the ingress of dirt
Driveshaft CV joint gaiter split or missing explained: what it means and what puts it right

Wording and categories reproduced from the DVSA inspection manual under the Open Government Licence. Frequencies are items per 100 failed class 4 tests across the DVSA anonymised MOT dataset; a clause with no figure was not recorded often enough to appear in any model’s top forty failure items. 2 of 13 clauses link to our own explanation.

Grading

What the categories mean

Dangerous: a direct and immediate risk to road safety or the environment. The vehicle fails and must not be driven until repaired, even to a garage.
Major: a defect that affects safety, the environment or other road users. The vehicle fails.
Minor: a defect with no significant effect on safety or the environment. Recorded on the certificate; the vehicle passes.

The full guide to defect grading

Section 6

Other sub-sections of body, structure and attachments

6.1.1General condition
6.1.2Exhaust system
6.1.3Fuel system
6.1.4Bumpers
6.1.5Spare wheel carrier (if fitted)
6.1.6Coupling mechanisms and towing equipment
6.1.8Engine mountings
6.2.1Body condition
6.2.2Cab and body mounting
6.2.3Doors and door catches
6.2.4Floor
6.2.5Driver’s seat
6.2.6Passenger seats
6.2.7Driving controls
6.2.8Cab steps (if fitted)
6.2.12Handgrips and footrests

All sections of the manual

Common questions

What does 6.1.7 mean on an MOT certificate?: It refers to sub-section 6.1.7 of the MOT inspection manual, "Transmission", within section 6, body, structure and attachments. The letter or letters after it — (a), (b)(i) and so on — identify the specific defect from the 13 listed here. 5 of them are graded Dangerous, 7 Major and 1 Minor.
Which transmission defect is recorded most often?: "A transmission shaft bearing excessively worn" (6.1.7 (b)(i)), recorded about 0.0 times per 100 failed MOT tests nationally.
Does a Minor defect fail the MOT?: No. a defect with no significant effect on safety or the environment. Recorded on the certificate; the vehicle passes. Major and Dangerous defects fail. A Dangerous defect also means the car must not be driven until it is repaired.