| Description | Date | Identifier | |
| The concluding page of a letter from Fredrik Ljungström, Managing Director of Aktiebolaget Spontan, regarding a demonstration during an exhibition. | 18th Nov 1927 | Box 156 \ 4 scan0020 | |
| Page from the 'Engineering' journal describing a single-lever control system for motor-cars. | 18th Nov 1927 | Box 156 \ 4 scan0021 | |
| Engineering journal page detailing the Ljungström single-lever control system for motor-cars with component illustrations. | 18th Nov 1927 | Box 156 \ 4 scan0022 | |
| Article from the journal 'Engineering' discussing the Ljungström single-lever control for motor-cars, with accompanying diagrams. | 18th Nov 1927 | Box 156 \ 4 scan0023 | |
| The design and operation of the Spontan automatic transmission gear. | 18th Nov 1927 | Box 156 \ 4 scan0024 | |
| Inventor, Mr. John Craig, and his proposition regarding a pump and variable gears. | 16th Oct 1928 | Box 156 \ 4 scan0025 | |
| Letter from an engineering firm proposing a new transmission system, called a booster. | 12th Oct 1928 | Box 156 \ 4 scan0026 | |
| Letter to John Craig regarding his invention of variable gears. | 16th Oct 1928 | Box 156 \ 4 scan0027 | |
| Potential adoption of new internal-geared transmissions and associated experimental designs. | 15th Jan 1929 | Box 156 \ 4 scan0028 | |
| List and analysis of easy-changing gearboxes and shifting devices from various manufacturers. | 15th Jan 1929 | Box 156 \ 4 scan0029 | |
| Comparison of 3-speed and 4-speed gearbox designs, their ratios, and their suitability for American drivers. | 15th Jan 1929 | Box 156 \ 4 scan0030 | |
| Recommendation for a gearbox and gearshift, suggesting a Stutz-type 3-speed with an emergency low. | 7th Feb 1929 | Box 156 \ 4 scan0031 | |
| Letter concerning advancements in American gearbox technology, particularly the 'Synchro-mesh' system. | 7th Feb 1929 | Box 156 \ 4 scan0032 | |
| Letter discussing the rapid adoption of convenience features in the American automotive market, such as front brakes, chassis lubrication, silent gearboxes, and chromium plating. | 30th Aug 1929 | Box 156 \ 4 scan0033 | |
| Progress on the 20 HP transmission's free wheel side shaft. | 30th Aug 1929 | Box 156 \ 4 scan0034 | |
| Letter regarding improved transmission, specifically the Sinclair Hydraulic Coupling and Millam Free Wheel. | 19th Sep 1932 | Box 156 \ 4 scan0035 | |
| Letter from an engineering company outlining the advantages of a hydraulic coupling and free wheel transmission system. | 24th Nov 1932 | Box 156 \ 4 scan0036 | |
| 20/25 transmission overrun rattle at 50 M.P.H. and a request to detail a solution. | 24th Nov 1932 | Box 156 \ 4 scan0037 | |
| Rattles on the Peregrine transmission and urging for a Chrysler-style damped spring drive clutch member. | 2nd Dec 1932 | Box 156 \ 4 scan0038 | |
| Causes and potential solutions for transmission rattles. | 12th Dec 1932 | Box 156 \ 4 scan0039 | |
| Conversation about clutch driven members with spring drives to address transmission rattles. | 23th Jan 1933 | Box 156 \ 4 scan0040 | |
| Issue of rattles in the transmission of 20/25 HP cars. | 9th May 1935 | Box 156 \ 4 scan0041 | |
| Inquiry regarding the Fleischel automatic transmission system and its potential use in England. | 16th May 1933 | Box 156 \ 4 scan0042 | |
| Rattles in the transmission and the lack of a suitable test car. | 9th May 1933 | Box 156 \ 4 scan0043 | |
| Fleischel transmission system and the possibility of testing the inventor's car in Paris. | 22th May 1933 | Box 156 \ 4 scan0044 | |
| Trip to France to test the Fleischel transmission in a Bentley car. | 24th May 1933 | Box 156 \ 4 scan0045 | |
| Following up on a conversation with Mr. Schneider about a demonstration of the Maybach transmission system. | 7th Jun 1933 | Box 156 \ 4 scan0046 | |
| The Maybach Transmission, agreeing with a previous communication. | 8th Jun 1933 | Box 156 \ 4 scan0047 | |
| Query regarding parts being prepared to fix transmission rattles on Dr. Daniels' car. | 9th Jun 1933 | Box 156 \ 4 scan0048 | |
| The preparation of parts to resolve issues with rattles in the transmission. | 13th Jun 1933 | Box 156 \ 4 scan0049 | |
| Follow-up memorandum concerning rattles in the transmission. | 11th Jul 1933 | Box 156 \ 4 scan0050 | |
| Rattles in the transmission and the availability of anti-rattle clutch parts. | 13th Jul 1933 | Box 156 \ 4 scan0051 | |
| Customer complaints about rattles in the transmission and potential solutions involving a damped flywheel or anti-rattle clutch centre. | 14th Jul 1933 | Box 156 \ 4 scan0052 | |
| The acquisition of two sets of parts. | 28th Jul 1933 | Box 156 \ 4 scan0053 | |
| Groans and rattle periods in Bentley drives and a proposed slipper drive solution. | 18th Dec 1933 | Box 156 \ 4 scan0054 | |
| Need for a propeller shaft damper for the Wraith transmission. | 8th Dec 1936 | Box 156 \ 4 scan0055 | |
| Addition of a balancing ring to the Phantom III transmission shaft. | 24th Dec 1936 | Box 156 \ 4 scan0056 | |
| Request to detail and create a dashpot deceleration control, an anti-chunking gadget, for the Phantom III transmission. | 17th Feb 1937 | Box 156 \ 4 scan0057 | |
| Blueprint of a deceleration control device for a Phantom III model. | 18th Feb 1937 | Box 156 \ 4 scan0058 | |
| Secret memo discussing the proactive design of a propeller shaft damper for the Wraith transmission. | 2nd Apr 1937 | Box 156 \ 4 scan0059 | |
| Requesting the detailing and preparation of parts for a new propeller shaft damper on a Phantom III transmission. | 2nd Apr 1937 | Box 156 \ 4 scan0060 | |
| Owner's complaint report number 139 regarding a transmission failure on chassis B.174.H.K. | 19th May 1937 | Box 156 \ 4 scan0061 | |
| Failure analysis report on rear wheel drivers showing sheared splines and cracks. | 13th May 1937 | Box 156 \ 4 scan0062 | |
| Letter discussing a potential inventor's new variable transmission system. | 17th Jun 1937 | Box 156 \ 4 scan0063 | |
| Description of a dynamic transmission system featuring a secondary motor, energy storage, and self-controlled operation. | 14th Jun 1937 | Box 156 \ 4 scan0064 | |
| Letter to the Sales Manager regarding a potential new dynamic transmission from an inventor. | 1st Jul 1937 | Box 156 \ 4 scan0065 | |
| Cover note regarding a variable transmission, attaching a letter and arranging a meeting. | 5th Jul 1937 | Box 156 \ 4 scan0066 | |
| Scheduling a visit for Mr. Last to the Works to discuss a variable transmission. | 7th Jul 1937 | Box 156 \ 4 scan0067 | |
| Letter to Mr. Owen arranging a visit to the Works for a Mr. Last before the holiday closure. | 8th Jul 1937 | Box 156 \ 4 scan0068 | |
| Letter arranging a visit to the works to see Mr. Robotham regarding the 'Last Transmission'. | 9th Jul 1937 | Box 156 \ 4 scan0069 | |
| Letter returning tracings and inquiring about a manual control for a speed change mechanism. | 15th Jul 1937 | Box 156 \ 4 scan0070 | |
| The 'Last' infinitely variable speed mechanism, detailing its operation, improvements, and disadvantages. | 4th Aug 1937 | Box 156 \ 4 scan0071 | |
| Device, likely a gearbox, and the decision process for its development. | 4th Aug 1937 | Box 156 \ 4 scan0072 | |
| Cover sheet for a report on transmission failures. | 17th Aug 1937 | Box 156 \ 4 scan0073 | |
| Report logging transmission failures, separated into 'Driver Dogs' and 'Road Shafts' categories. | 5th Jul 1937 | Box 156 \ 4 scan0074 | |
| Transmission and road shaft failures with corresponding vehicle service histories. | 11th Aug 1937 | Box 156 \ 4 scan0075 | |
| Shaft failures and maintenance history for two vehicles. | 11th Aug 1937 | Box 156 \ 4 scan0076 | |
| Clicking noise in the Wraith transmission, its cause, and potential solutions. | 2nd Feb 1938 | Box 156 \ 4 scan0077 | |
| Stiffened flange piece for the Wraith III transmission shaft. | 25th Feb 1938 | Box 156 \ 4 scan0078 | |
| Modification to the Wraith III transmission shaft coupling to prevent stretching and distortion. | 2nd Mar 1938 | Box 156 \ 4 scan0079 | |
| Request to manufacture a coupling for the Wraith transmission. | 25th May 1938 | Box 156 \ 4 scan0080 | |
| Operation of a General Motors epicyclic gearbox fitted to an Oldsmobile. | 26th Nov 1938 | Box 156 \ 4 scan0081 | |
| Arrangement for a car fitted with a hydraulic transmission by Turbo Transmitters Ltd. to be made available at Derby. | 24th May 1939 | Box 156 \ 4 scan0082 | |
| Hydraulic transmissions and experiences with Turbo Transmitters Limited. | 24th May 1939 | Box 156 \ 4 scan0083 | |
| Test run of a hydraulic gearbox transmitter from Turbo Transmitters Ltd. | 18th May 1939 | Box 156 \ 4 scan0084 | |
| Letter discussing the performance, advantages, and potential applications of a turbo transmission. | 18th May 1939 | Box 156 \ 4 scan0085 | |
| Engine temperature and fitting a Bentley engine and axle to a car. | 22th Aug 1938 | Box 156 \ 4 scan0086 | |
| Reprint from the publication 'ENGINEERING' of a paper on a hydro-kinetic power transmitter. | 22th Aug 1938 | Box 156 \ 4 scan0087 | |
| Vehicle road tests, detailing hill-climbing performance, fuel consumption, and transmission behavior, accompanied by illustrative diagrams. | 2nd Sep 1938 | Box 156 \ 4 scan0088 | |
| Technical paper reprint from the 'ENGINEERING' journal on the Hydro-Kinetic Power Transmitter, with performance tests and component comparisons. | 2nd Sep 1938 | Box 156 \ 4 scan0089 | |
| Analysis of the design principles and fluid dynamics of a hydro-kinetic power transmitter, including diagrams of fluid flow. | 2nd Sep 1938 | Box 156 \ 4 scan0090 | |
| Design description of a hydraulic transmitter, focusing on the fluid dynamics and construction of its components. | 2nd Sep 1938 | Box 156 \ 4 scan0091 | |
| Analysis of fluid dynamics within a transmitter, focusing on vane and duct characteristics with accompanying diagrams. | 31th May 1939 | Box 156 \ 4 scan0092 | |
| Letter to Turbo Transmissions Ltd. arranging a trial of their new hydraulic transmission. | 31th May 1939 | Box 156 \ 4 scan0093 | |
| Letter from Turbo Transmitters rescheduling an appointment to try a transmitter. | 5th Jun 1939 | Box 156 \ 4 scan0094 | |
| Letter to Turbo Transmitters Ltd. to arrange a date to try the Turbo Transmitter. | 28th Jun 1939 | Box 156 \ 4 scan0095 | |
| Follow-up memo regarding scheduling an appointment with Turbo Transmitters Ltd. | 28th Jun 1939 | Box 156 \ 4 scan0096 | |
| Unaccounted 8% loss of horsepower in the transmission. | 30th Jun 1939 | Box 156 \ 4 scan0097 | |
| Evaluating a 'Turbo Transmitter' equipped car against a Humber Super Snipe and comparing the system to Ford's. | 7th Jul 1939 | Box 156 \ 4 scan0098 | |
| Commentary on the Salerni scheme in comparison to Sinclair's, involving fluid flywheels and epicyclic combinations. | 8th Jul 1939 | Box 156 \ 4 scan0099 | |
| Test report on a Turbo Transmitter fitted to a Humber Super Snipe. | 7th Jul 1939 | Box 156 \ 4 scan0100 | |
| Review of the drawbacks and technical points of a Turbo Transmitter for potential use in a car. | 7th Jul 1939 | Box 156 \ 4 scan0101 | |
| Attributes and disadvantages of a product for an owner who spends most of their time in London. | 7th Jul 1939 | Box 156 \ 4 scan0102 | |
| Letter to Turbo Transmitters Ltd. regarding the testing of a hydraulic transmission and a potential solid drive feature. | 10th Jul 1939 | Box 156 \ 4 scan0103 | |
| Performance and issues of a Turbo Transmitter in a Humber Snipe. | 11th Jul 1939 | Box 156 \ 4 scan0104 | |
| Letter from Turbo Transmitters discussing solid drive arrangements and engine fussiness in comparison to a Humber. | 12th Jul 1939 | Box 156 \ 4 scan0105 | |
| Transmission vibration issues in a 10.B.V Coupé and the series of tests conducted to find a cure. | 9th Aug 1939 | Box 156 \ 4 scan0106 | |
| Continued report on isolating a centre joint using rubber and felt to reduce noise and vibration. | 9th Aug 1939 | Box 156 \ 4 scan0107 | |
| Diagram of a mock-up for a noise-insulated centre bracket for a propeller shaft. | 15th Nov 1939 | Box 156 \ 4 scan0108 | |
| Reviewing transmission options, comparing split and single propeller shafts for various car models. | 15th Nov 1939 | Box 156 \ 4 scan0109 | |
| Gearbox and propeller shaft options for the 'Rippletto' and 'Myth' car models. | 15th Nov 1939 | Box 156 \ 4 scan0110 | |
| Letter to C.L. Breeden regarding a plant visit, post-war manufacturing, and testing of Turbo transmitters. | 30th Dec 1939 | Box 156 \ 4 scan0111 | |
| Letter to C.E. Breeden discussing the market viability and drawbacks of a Turbo transmitter. | 30th Nov 1939 | Box 156 \ 4 scan0112 | |
| Letter discussing a recent conversation about engines and a personal order for a 'River 10'. | 6th Dec 1939 | Box 156 \ 4 scan0113 | |
| Postscript memo discussing the trial of a Moore's Turbo Transmitter. | 7th Dec 1939 | Box 156 \ 4 scan0114 | |
| Letter to G.R.N. Minchin regarding a discussion with Wilmot-Breeden about a Turbo transmitter. | 7th Dec 1939 | Box 156 \ 4 scan0115 | |
| Letter from Wilmot-Breeden Ltd to A. Robotham regarding a hydraulic torque converter. | 7th Dec 1939 | Box 156 \ 4 scan0116 | |
| Letter discussing potential improvements to a fluid dynamics device, such as a pump or torque converter, and seeking a technical judgement. | 7th Dec 1939 | Box 156 \ 4 scan0117 | |
| Letter discussing the Bendix turbo flywheel gear with an incorporated small epicyclic for an emergency low gear and reverse. | 11th Dec 1939 | Box 156 \ 4 scan0118 | |
| Letter from Peto & Radford to W.A. Robotham regarding a proposed meeting. | 22th Aug 1940 | Box 156 \ 4 scan0119 | |
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