| Description | Date | Identifier | |
| Sluggishness in the India change speed lever and requesting tests to inform modifications for a new gearbox. | 8th Apr 1926 | Box 15 \ 5 Scan005 | |
| Notice detailing modifications and corrections for the E.A.C.VIII gearbox, including a list of updated part numbers. | 29th Apr 1926 | Box 15 \ 5 Scan006 | |
| Requested modifications to a gearbox mechanism, including sketches. | 26th Jun 1926 | Box 15 \ 5 Scan007 | |
| Examination of a faulty change speed mechanism on a 12-EX car, identifying the cause and the implemented solution. | 8th Jul 1926 | Box 15 \ 5 Scan008 | |
| Diagram of a Change Speed Mechanism showing deflection measurements in inches. | 8th Jul 1926 | Box 15 \ 5 Scan009 | |
| The reverse side of a document page featuring a red archival stamp. | 8th Jul 1926 | Box 15 \ 5 Scan010 | |
| Alterations to the rear brake differentials and related components. | 27th Aug 1926 | Box 15 \ 5 Scan011 | |
| Proposal to fit 13/47 ratio bevels in the rear axle of the EAC.7 chassis and instruct a suitable speedometer. | 10th Sep 1926 | Box 15 \ 5 Scan012 | |
| Standardisation of 'D' Type C.H.N.S. keyed type change gear shaft with a modified bush and spring. | 24th Sep 1926 | Box 15 \ 5 Scan013 | |
| Testing and implementation of a new direct drive scheme for the Phantom gearbox, urging for it to replace the old system. | 4th Oct 1926 | Box 15 \ 5 Scan014 | |
| Experimental application of a direct drive scheme to the Phantom gear box. | 5th Oct 1926 | Box 15 \ 5 Scan015 | |
| Costed alteration to a standard sheet for Change Gear and Brake Operating Mechanism. | 13th Oct 1926 | Box 15 \ 5 Scan016 | |
| Alteration to the 'D' Type keyed change gear shaft with a modified bush and bearing. | 24th Sep 1926 | Box 15 \ 5 Scan017 | |
| Standardisation of chassis parts, noting an alteration to improve the design of the change gear and brake operating mechanism. | 13th Oct 1926 | Box 15 \ 5 Scan018 | |
| Standardisation of a gearbox with modified selectors, pinions, and sliding wheels for definite end clearance. | 1st Oct 1926 | Box 15 \ 5 Scan019 | |
| Modifications to a hypoid gear rear axle gearbox. | 28th Oct 1926 | Box 15 \ 5 Scan020 | |
| Design and specifications for a new 11/41 ratio hypoid gear. | 29th Oct 1926 | Box 15 \ 5 Scan021 | |
| Standardisation sheet for the Phantom gearbox, questioning the effect on existing stock. | 1st Nov 1926 | Box 15 \ 5 Scan022 | |
| Standardisation sheet concerning the Phantom Gearbox. | 4th Nov 1926 | Box 15 \ 5 Scan023 | |
| Provision of high gear ratios for 40/50 HP and 20 HP cars. | 16th Nov 1926 | Box 15 \ 5 Scan024 | |
| The assembly of a servo worm gear, requesting a specimen pair from Messrs. Bostock & Bramley. | 11th Nov 1927 | Box 15 \ 5 Scan025 | |
| Suppliers and design improvements for an integral gearbox servo worm drive. | 24th Nov 1927 | Box 15 \ 5 Scan026 | |
| Drawings for the EAC.10 gearbox and clutch casing, detailing modifications. | 25th Nov 1927 | Box 15 \ 5 Scan027 | |
| Modifications and axle ratio performance for the Sports Phantom, chassis 10-EX. | 29th Nov 1926 | Box 15 \ 5 Scan028 | |
| Oversight in brake operation and proposed modifications for the EAC-7 chassis. | 16th Dec 1926 | Box 15 \ 5 Scan029 | |
| The testing and fitting of a toothed direct drive motion shaft for a Phantom gearbox. | 17th Dec 1926 | Box 15 \ 5 Scan030 | |
| Modifications to the cutout operation mechanism, referencing Phantom designs. | 20th Jan 1927 | Box 15 \ 5 Scan031 | |
| Problem with low force from the friction head in the servo linkage and a proposed fix using a new square wire spring. | 7th Apr 1927 | Box 15 \ 5 Scan032 | |
| Design and use of different hypoid gears, specifically 1' and 2' off-set types. | 14th Apr 1927 | Box 15 \ 5 Scan033 | |
| Gear ratio for the EAC.10 gearbox speedometer drive. | 1st Dec 1927 | Box 15 \ 5 Scan034 | |
| The speedometer drive ratio for the EAC.10 gearbox to order the correct part. | 7th Dec 1927 | Box 15 \ 5 Scan035 | |
| Arrangement of the clutch, front brake differential, and related components, referencing several schematics. | 1st Dec 1927 | Box 15 \ 5 Scan036 | |
| Sending a filler for the EAC.10 gearbox and questioning the purpose of a second filler on the related EAC.7 model. | 9th Dec 1927 | Box 15 \ 5 Scan037 | |
| Pedal arrangement for the EAC.10 gearbox, referencing drawings N.schs. 2449 and 2531. | 23th Dec 1927 | Box 15 \ 5 Scan038 | |
| Query regarding the practicality of removing the gearbox without the engine on the EAC.10 model, considering the position of the cross member. | 1st Jan 1928 | Box 15 \ 5 Scan039 | |
| Correction to the EAC.10 gearbox casting. | 6th Feb 1928 | Box 15 \ 5 Scan040 | |
| The arrangement of brake differentials and the connection to the servo. | 2nd Feb 1928 | Box 15 \ 5 Scan041 | |
| Confirming the dispatch of detailed drawings for a change-speed gearbox. | 17th Feb 1928 | Box 15 \ 5 Scan042 | |
| Design alterations, focusing on the importance and challenges of reusing existing parts to minimize costs. | 13th Mar 1928 | Box 15 \ 5 Scan043 | |
| Delay in introducing smaller speedometers and the cost implications for various car series. | 20th Jul 1928 | Box 15 \ 5 Scan044 | |
| Design change for the brake countershaft on the gearbox, proposing a forged part. | 28th Aug 1928 | Box 15 \ 5 Scan045 | |
| Requesting clarification on the weight saving on the 'SS' engine unit gearbox. | 18th Sep 1928 | Box 15 \ 5 Scan046 | |
| Standardisation of a small dial speedometer for the 40/50 chassis. | 3rd Sep 1928 | Box 15 \ 5 Scan047 | |
| Standardisation form for a new chassis part, detailing the first chassis for fitting, test date, and associated costs. | 3rd Nov 1928 | Box 15 \ 5 Scan048 | |
| Modifications to the 'SS' gearbox undershield and associated parts. | 10th Oct 1928 | Box 15 \ 5 Scan049 | |
| Noisy gearboxes on the New Phantom due to the exhaust pipe affecting the alignment of the side shafts. | 15th Oct 1928 | Box 15 \ 5 Scan050 | |
| Letter discussing improving vehicle acceleration by adopting a lower gear and a combined freewheel and clutch mechanism. | 24th Oct 1928 | Box 15 \ 5 Scan051 | |
| Gearbox design, focusing on achieving a 3rd speed using an epicyclic gear unit as an alternative to a standard gearbox. | 24th Oct 1928 | Box 15 \ 5 Scan052 | |
| Alternative gearbox designs, focusing on the advantages of epicyclic units for achieving silent operation. | 7th Nov 1928 | Box 15 \ 5 Scan053 | |
| Methods for improving vehicle acceleration, including engine power and gearbox design. | 7th Nov 1928 | Box 15 \ 5 Scan054 | |
| Alternative gearbox designs, including epicyclic units, freewheels, and their controls. | 12th Nov 1928 | Box 15 \ 5 Scan055 | |
| Fixing an oil leak on 'SS' engines by modifying the timing gear lubrication system. | 12th Nov 1928 | Box 15 \ 5 Scan056 | |
| Sketch showing a restriction in a timing gears oil pipe for a Super Sports model. | 12th Nov 1928 | Box 15 \ 5 Scan057 | |
| Instruction from Mr. Royce to use a hardened steel bush and shaft to resolve a binding issue with the 'SS' change speed mechanism. | 28th Nov 1928 | Box 15 \ 5 Scan058 | |
| Specifying a different gearbox end for the speedometer drive on the 'SS' car compared to the standard 40/50 model. | 28th Nov 1928 | Box 15 \ 5 Scan059 | |
| Requesting the fitting of 4 solid engine feet and an experimental bracket to chassis 19-EX. | 13th Dec 1928 | Box 15 \ 5 Scan060 | |
| The difficulty of removing the gearbox on the 'SS' car, proposing a detachable front cross member as a solution. | 13th Dec 1928 | Box 15 \ 5 Scan061 | |
| Fault in the 'SS' gearbox preventing easy engagement of the reverse gear. | 17th Dec 1928 | Box 15 \ 5 Scan062 | |
| Investigation into difficulty engaging reverse gear on an 'SS' model car. | 17th Dec 1928 | Box 15 \ 5 Scan063 | |
| Visit by Mr. Hardy to Derby concerning the L.H. SS. gearbox. | 18th Dec 1928 | Box 15 \ 5 Scan064 | |
| Pause in the development of the L.H. SS. Gearbox, offering to share existing blueprints. | 20th Dec 1928 | Box 15 \ 5 Scan065 | |
| Modifications to the speedometer drive to create a single drive, omitting the one for the screen wiper. | 12th Jan 1929 | Box 15 \ 5 Scan066 | |
| Arguing for the adoption of an electrical screenwiper drive as standard, deleting the mechanical drive. | 30th Jan 1929 | Box 15 \ 5 Scan067 | |
| From EFC to Mr. Clough requesting details on axle ratios, tyre diameter, and gearbox ratios. | 1st Feb 1929 | Box 15 \ 5 Scan068 | |
| Specifications for the S.S. Chassis, including rear axle ratio, tyre options, and gearbox ratios. | 1st Feb 1929 | Box 15 \ 5 Scan069 | |
| Specification sheet for S.S. Chassis gear ratios, including engine and dynamo RPMs at various speeds. | 4th Feb 1929 | Box 15 \ 5 Scan070 | |
| Recommendation for a detachable front subframe cross member to facilitate the removal of the 'SS' gearbox. | 14th Feb 1929 | Box 15 \ 5 Scan071 | |
| Letter discussing the results of the 19-EX car report, focusing on lubrication and gearbox oil leak resolutions. | 19th Feb 1929 | Box 15 \ 5 Scan072 | |
| Instructions for fitting a baffle plate and new tyres, including vehicle logistical arrangements. | 5th Mar 1929 | Box 15 \ 5 Scan073 | |
| And comparing different gearbox designs, focusing on 3rd speed, silence, and ease of gear change. | 5th Mar 1929 | Box 15 \ 5 Scan074 | |
| Page 2 of a memo discussing American schemes and the performance of an SS vehicle after 14,000 miles. | 13th Mar 1929 | Box 15 \ 5 Scan075 | |
| From D.A. to R. regarding the progress and delays on change gear schemes, including the free wheel and epicyclic gear box. | 13th Mar 1929 | Box 15 \ 5 Scan076 | |
| Different types of change-speed gearboxes, categorized by their primary benefits such as ease of changing and silence. | 25th Mar 1929 | Box 15 \ 5 Scan077 | |
| Comparative analysis of different gearbox and coupling schemes, page 2. | 25th Mar 1929 | Box 15 \ 5 Scan078 | |
| Analysis of gearbox designs, focusing on the advantages and disadvantages of internal mesh with dog clutches. | 25th Mar 1929 | Box 15 \ 5 Scan079 | |
| Gearbox operation, discussing difficulties with specific types and a proposal for an epicyclic gear system. | 3rd Apr 1929 | Box 15 \ 5 Scan080 | |
| Modifications to a 3rd-speed easy-change gearbox, including diagrams. | 3rd Apr 1929 | Box 15 \ 5 Scan081 | |
| Typed memorandum with a small sketch discussing the assembly and testing of a freewheel mechanism. | 14th Apr 1929 | Box 15 \ 5 Scan082 | |
| Proposal for an easy change gearbox device using suction to operate a clutch, potentially for a provisional patent. | 14th Apr 1929 | Box 15 \ 5 Scan083 | |
| Improvements to the S.S. gearbox by modifying gear tooth chamfer angles. | 1st May 1929 | Box 15 \ 5 Scan084 | |
| The optimal gearbox oil height from a 10,000-mile test and instructing dipsticks to be marked. | 25th May 1939 | Box 15 \ 5 Scan085 | |
| Recommendation for S.S. and India 1V speedometer cable revolutions per mile standards. | 4th Jul 1929 | Box 15 \ 5 Scan086 | |
| Urgent memo detailing a decision to produce the last 70 'O' Series chassis with a larger bore engine and improved gears. | 24th Jun 1929 | Box 15 \ 5 Scan087 | |
| Gearbox problems and potential solutions for a more silent and easily changed gear. | 3rd Jun 1929 | Box 15 \ 5 Scan088 | |
| The Salerni coupling, its disadvantages, and proposed modifications to improve its function with the clutch and gear change mechanism. | 3rd Jun 1929 | Box 15 \ 5 Scan089 | |
| Potential gearbox improvements using helical gears, a jaw clutch, and the Salerni coupling. | 8th Jun 1929 | Box 15 \ 5 Scan090 | |
| Correction to scheme 2899, regarding the method for retaining a large ball bearing for an experimental Salerni coupling gearbox. | 8th Jun 1929 | Box 15 \ 5 Scan091 | |
| Scheme for a silent 3rd speed gearbox using single and double helical gears. | 2nd Jun 1929 | Box 15 \ 5 Scan092 | |
| Arranging a meeting at 113 Ladbrook Road to discuss the speedometer on car 18-EX. | 17th Jul 1929 | Box 15 \ 5 Scan093 | |
| The difficulty of changing '33' gear boxes and a proposed modification to the rear suspension bracket. | 22th Jul 1929 | Box 15 \ 5 Scan094 | |
| Responding to feedback on the coachwork, speedometer, and steering for car 18-EX. | 26th Jul 1929 | Box 15 \ 5 Scan095 | |
| Test results for climbing Ticknall Hill in car 10-EX, comparing different driving methods and other vehicles. | 22th Aug 1929 | Box 15 \ 5 Scan096 | |
| Instructions regarding an Epicyclic Third Speed Gear, its schematic, and fitting to car 14-EX. | 21th Sep 1929 | Box 15 \ 5 Scan097 | |
| Epicyclic 3rd speed gear, requesting a new clutch spring and alteration of clutch clearance. | 21th Sep 1929 | Box 15 \ 5 Scan098 | |
| Investigation into the comparative merits and noise levels of spur, epicyclic, and internal gears for a silent 3rd-speed gearbox. | 24th Dec 1929 | Box 15 \ 5 Scan099 | |
| Requesting modifications to sliding dogs for the 14-EX car silent third speed gearbox. | 31th Dec 1929 | Box 15 \ 5 Scan100 | |
| Modification drawing for 3 1/2' & 7 1/4' gear dogs, part number G 77976. | 30th Dec 1914 | Box 15 \ 5 Scan101 | |
| Stamped document page with faint, illegible text. | 30th Dec 1929 | Box 15 \ 5 Scan102 | |
| Causes and fixes for oil leaks from the No.2-WJ gearbox. | 13th Jan 1930 | Box 15 \ 5 Scan103 | |
| Development of an improved and silent 4-speed car change speed gear. | 13th Jan 1930 | Box 15 \ 5 Scan104 | |
| | | | |
