| Description | Date | Identifier | |
| Modification to the reverse shaft bush for Spectre and Wraith gearboxes. | 26th Sep 1934 | Box 94 \ 1 scan0039 | |
| Modifications to the Spectre gearbox, specifically the reverse gear oil duct and the location of the drain plug. | 26th Sep 1934 | Box 94 \ 1 scan0040 | |
| Modifications to the Spectre Gearbox to facilitate assembly and dismantling. | 27th Sep 1934 | Box 94 \ 1 scan0041 | |
| Modifications to the Spectre Gearbox 2nd speed actuating mechanism. | 2nd Oct 1934 | Box 94 \ 1 scan0042 | |
| Alterations for the second 'Spectre Gearbox' casting. | 8th Oct 1934 | Box 94 \ 1 scan0043 | |
| List of modifications and additional parts for experimental purposes, page 2. | 24th Sep 1934 | Box 94 \ 1 scan0044 | |
| Spring-loaded ball location for the 1st speed wheel in Spectre and Wraith gearboxes. | 13th Oct 1934 | Box 94 \ 1 scan0045 | |
| Modifications to the Spectre Gearbox bearing surface and washer. | 19th Oct 1934 | Box 94 \ 1 scan0046 | |
| Arrangement of couplings in the Spectre Transmission and a modification to the detachable coupling. | 19th Oct 1934 | Box 94 \ 1 scan0047 | |
| Request to alter the Spectre and Wraith gearboxes by increasing the number of bolts serving as dowels. | 24th Oct 1934 | Box 94 \ 1 scan0048 | |
| Modifications to the Spectre Gearbox selector lock housing to save cost and weight. | 24th Oct 1934 | Box 94 \ 1 scan0049 | |
| Placement of casing bolts on Spectre and Wraith gearboxes. | 29th Oct 1934 | Box 94 \ 1 scan0050 | |
| Modifications to the servo drive for the Spectre & Wraith gearboxes. | 29th Oct 1934 | Box 94 \ 1 scan0051 | |
| Insufficient coring of the oil return passage for the bearing on Spectre Gearbox servo drive casings. | 29th Oct 1934 | Box 94 \ 1 scan0052 | |
| Specification for the third Spectre gearbox with modifications to the casing. | 1st Nov 1934 | Box 94 \ 1 scan0053 | |
| List of modifications for gearbox components including the servo shaft, casing, speedometer drive, and synchromesh pieces. | 1st Nov 1934 | Box 94 \ 1 scan0054 | |
| Revision to the Spectre gearbox speedometer drive. | 1st Nov 1934 | Box 94 \ 1 scan0055 | |
| Specification document for the third Spectre gearbox, detailing modifications to the casing. | 1st Nov 1934 | Box 94 \ 1 scan0056 | |
| List of modifications and instructions for a vehicle's gearbox and related components. | 1st Nov 1934 | Box 94 \ 1 scan0057 | |
| Modification to the Spectre Gearbox actuating sleeve to reduce expense. | 5th Nov 1934 | Box 94 \ 1 scan0058 | |
| The investigation of larger servos for Spectre and Wraith gearboxes and potential casing alterations. | 5th Nov 1934 | Box 94 \ 1 scan0059 | |
| Alterations to the dimensions of flanges on Spectre and Wraith gearboxes. | 5th Nov 1934 | Box 94 \ 1 scan0060 | |
| Modifications to the Spectre Gearbox casing to accommodate a larger servo. | 14th Nov 1934 | Box 94 \ 1 scan0061 | |
| Instructing to hold up production of specific Spectre and Wraith gearbox parts pending alterations. | 21th Nov 1934 | Box 94 \ 1 scan0062 | |
| The behaviour of the first all-helical gearbox. | 23th Nov 1934 | Box 94 \ 1 scan0063 | |
| Preliminary report on the testing and performance of the Spectre All Helical Gearbox. | 23th Nov 1934 | Box 94 \ 1 scan0064 | |
| Gearbox issues, including 2nd gear disengagement, jumping out of gear, and slack in the 3rd motion shaft. | 23th Nov 1934 | Box 94 \ 1 scan0065 | |
| Modifications to the Spectre Gearbox. | 29th Nov 1934 | Box 94 \ 1 scan0066 | |
| Design modification for Spectre and Wraith gearboxes concerning oil flow. | 4th Dec 1934 | Box 94 \ 1 scan0067 | |
| Requested modifications for an all-helical gearbox. | 5th Dec 1934 | Box 94 \ 1 scan0068 | |
| With diagram detailing modifications to a Spectre Gearbox to correct a 2nd speed gear fault. | 6th Dec 1934 | Box 94 \ 1 scan0069 | |
| Trial of high Brinell surface hardness for steel housings in Spectre and Wraith gearboxes. | 7th Dec 1934 | Box 94 \ 1 scan0070 | |
| Alterations to the gearbox attachments for Spectre and Wraith models. | 7th Dec 1934 | Box 94 \ 1 scan0071 | |
| To hold up work on specific parts for the Spectre and Wraith gearboxes due to a meshing issue. | 12th Dec 1934 | Box 94 \ 1 scan0072 | |
| Modifications to the Spectre Gearbox's second speed to prevent the gear from disengaging. | 14th Dec 1934 | Box 94 \ 1 scan0073 | |
| Methods for diagnosing noise in experimental gearboxes, including copper plating gears. | 31th Dec 1934 | Box 94 \ 1 scan0074 | |
| Request for experimental shorter bushes for the Spectre Gearbox to reduce oil drag. | 1st Jan 1935 | Box 94 \ 1 scan0075 | |
| Design for the Spectre Gearbox's 2nd speed pieces. | 2nd Jan 1935 | Box 94 \ 1 scan0076 | |
| The application of needle roller bearings to the Spectre Gearbox. | 3rd Jan 1935 | Box 94 \ 1 scan0077 | |
| New higher ratio 1st speed gear for the Spectre Gearbox to improve cold operation and reduce stress. | 8th Jan 1936 | Box 94 \ 1 scan0078 | |
| Outlining improvements for the Spectre Gearbox regarding heavy operation when cold. | 3rd Jan 1935 | Box 94 \ 1 scan0079 | |
| 2nd and 3rd speeds compared to the S.M. 2nd Phantom and the measurement of oil drag. | 3rd Jan 1935 | Box 94 \ 1 scan0080 | |
| Confirming arrangements to rig-test a Spectre gearbox casting to resolve oil drag problems. | 5th Jan 1935 | Box 94 \ 1 scan0081 | |
| Secret memo regarding the specifications and status of experimental gearboxes for the Spectre car. | 14th Jan 1935 | Box 94 \ 1 scan0082 | |
| Specification sheet detailing modifications for a 3rd gearbox, with comparisons to previous versions. | 14th Jan 1935 | Box 94 \ 1 scan0083 | |
| List of modifications, numbered 16 to 30, detailing changes to various mechanical components. | 14th Jan 1935 | Box 94 \ 1 scan0084 | |
| List of alternative parts and modifications for trial on a vehicle's transmission system. | 14th Jan 1935 | Box 94 \ 1 scan0085 | |
| Correct Durometer hardness for rubbers in the Spectre gearbox, requesting an update to Drawing G.56304. | 17th Jan 1935 | Box 94 \ 1 scan0086 | |
| Modifications to a fractured sleeve for a Spectre Gearbox motion shaft. | 18th Jan 1935 | Box 94 \ 1 scan0087 | |
| Strengthened flanges for Spectre and Wraith gearbox shafts. | 18th Jan 1935 | Box 94 \ 1 scan0088 | |
| Modification to the Spectre Gearbox stay for improved clutch coupling accessibility. | 6th Feb 1935 | Box 94 \ 1 scan0089 | |
| Dynamometer testing of a Spectre All Helical Gearbox, detailing a failure in 3rd gear and subsequent modifications. | 7th Feb 1935 | Box 94 \ 1 scan0090 | |
| Requesting a new design for a more flexible gearbox suspension to increase silence, referencing the Terraplane engine mounting. | 11th Feb 1935 | Box 94 \ 1 scan0091 | |
| Request to the Order Office for six sets of Spectre gearbox front rubber supports with a revised material specification. | 13th Feb 1935 | Box 94 \ 1 scan0092 | |
| Modifications to the Spectre Gearbox rubber mounting to improve silence. | 14th Feb 1935 | Box 94 \ 1 scan0093 | |
| Permanent scheme and modifications for the 3rd box of the Spectre gearbox. | 16th Feb 1935 | Box 94 \ 1 scan0094 | |
| The Spectre Gearbox Test, run on the Dynamometer on the Vulture Car. | 18th Feb 1935 | Box 94 \ 1 scan0095 | |
| Instruction regarding the hardening of surfaces for components within the Spectre and Wraith gearboxes. | 20th Feb 1935 | Box 94 \ 1 scan0096 | |
| Hardening instructions for the 1st speed retaining plate on Spectre and Wraith gearboxes. | 21th Feb 1935 | Box 94 \ 1 scan0097 | |
| Experimental department report on the dynamometer testing of the Spectre All Helical Gearbox. | 21th Feb 1935 | Box 94 \ 1 scan0098 | |
| The dynamometer and road testing of the Spectre All Helical Gearbox. | 21th Feb 1935 | Box 94 \ 1 scan0099 | |
| Two alterations for the Spectre Gearbox 1st and Reverse gears. | 25th Feb 1935 | Box 94 \ 1 scan0100 | |
| Assembly difficulty of the Spectre Gearbox due to incorrect bracket placement. | 28th Feb 1935 | Box 94 \ 1 scan0101 | |
| Instruction to delete the boss on the gearbox arm for the Spectre and Wraith models. | 28th Feb 1935 | Box 94 \ 1 scan0102 | |
| Temporary arrangement for the Spectre Gearbox using ball bearings in place of roller bearings. | 8th Mar 1935 | Box 94 \ 1 scan0103 | |
| Modified pressure angles for the Spectre Gearbox teeth, referencing a Cadillac design. | 12th Mar 1935 | Box 94 \ 1 scan0104 | |
| Requesting the measurement of the gearbox end float for the Spectre No. 2 Car. | 13th Mar 1935 | Box 94 \ 1 scan0105 | |
| Secret memo regarding pressure angle adjustments for the Spectre Gear Box, N. Scheme 4414. | 28th Mar 1935 | Box 94 \ 1 scan0106 | |
| Corrections for the Spectre Gearbox. | 28th May 1935 | Box 94 \ 1 scan0107 | |
| Trial of a Spectre gearbox using coarse pitch gears with a 45-degree helix. | 28th Mar 1935 | Box 94 \ 1 scan0108 | |
| Modification to the frame for the Spectre gearbox, referencing updated drawings. | 3rd Apr 1935 | Box 94 \ 1 scan0109 | |
| Experimental figures for end load produced by torque on a 5/8' nut with 20 threads per inch. | 8th Apr 1935 | Box 94 \ 1 scan0110 | |
| Proposal for an experiment to reduce gear noise in the Spectre Gearbox by increasing shaft stiffness. | 9th Apr 1935 | Box 94 \ 1 scan0111 | |
| Modifications to a layshaft and 3rd motion shaft to handle thrust loads for an experiment. | 9th Apr 1935 | Box 94 \ 1 scan0112 | |
| Blueprint for experimental gears clamped endwise for the Spectre Gearbox. | 10th Apr 1935 | Box 94 \ 1 scan0113 | |
| Status of ongoing experiments on the Spectre gearbox. | 11th Apr 1935 | Box 94 \ 1 scan0114 | |
| List of features for a trial on a Spectre Gearbox. | 11th Apr 1935 | Box 94 \ 1 scan0115 | |
| Modifications to the SPECTRE gearbox with a horizontal hand brake. | 25th Apr 1935 | Box 94 \ 1 scan0116 | |
| List of experiments to be conducted on the Spectre gearbox rig. | 2nd May 1935 | Box 94 \ 1 scan0117 | |
| Experiment for supplying oil to bearings for the Spectre Gearbox. | 3rd May 1935 | Box 94 \ 1 scan0118 | |
| Modifications to the Spectre Gearbox inspection cover and associated components. | 4th May 1935 | Box 94 \ 1 scan0119 | |
| Oil drag tests on a Spectre gearbox and a request for modification. | 10th May 1935 | Box 94 \ 1 scan0120 | |
| Request to trial an aluminium change speed bracket for the Spectre Gear Lever to reduce noise. | 15th May 1935 | Box 94 \ 1 scan0121 | |
| Secret memorandum discussing the replacement of standard bearings with special ball bearings for the Spectre Gearbox. | 17th May 1935 | Box 94 \ 1 scan0122 | |
| Proposing the use of a larger standard ball bearing without waiting for test results. | 17th May 1935 | Box 94 \ 1 scan0123 | |
| Urgent testing of ball bearings for the Spectre Gearbox. | 17th May 1935 | Box 94 \ 1 scan0124 | |
| Secret memo outlining suggestions for modifications to the Spectre Gearbox, Governor Control, and Hand Brake Equaliser. | 17th May 1935 | Box 94 \ 1 scan0125 | |
| Alterations to coil springs and the attachment of a schedule for a filter retaining spring ring. | 17th May 1935 | Box 94 \ 1 scan0126 | |
| Investigation into noise and 'chunking' issues with the Spectre gearbox, detailing experiments and comparisons with other models. | 21th May 1935 | Box 94 \ 1 scan0127 | |
| Comparison table of gearbox backlash test results for various models. | 21th May 1935 | Box 94 \ 1 scan0128 | |
| Secret memo regarding weight reduction modifications for the Spectre Gearbox. | 21th May 1935 | Box 94 \ 1 scan0129 | |
| Specifications and issues for the Spectre 3-S-1 gearbox 10,000-mile test. | 24th May 1935 | Box 94 \ 1 scan0130 | |
| Oil drag tests conducted on a Spectre 4.HS gearbox, noting the effects of temperature. | 27th May 1935 | Box 94 \ 1 scan0131 | |
| Graph showing the gear lever torque required to disengage first gear relative to the torque applied to the third motion shaft. | 7th May 1935 | Box 94 \ 1 scan0132 | |
| Oil drag and power loss test results for the Spectre 4-speed gearbox. | 4th May 1935 | Box 94 \ 1 scan0133 | |
| Secret memo detailing pattern alterations for a friction damper and modifications to the gear lever bracket for the Spectre Gearbox. | 31th May 1935 | Box 94 \ 1 scan0134 | |
| Material change for the gearbox plunger housing to reduce weight, using alloys RR.50 or RR.56. | 31th May 1935 | Box 94 \ 1 scan0135 | |
| Lubrication scheme test for the 3rd motion shaft of a Spectre gearbox. | 6th Jun 1935 | Box 94 \ 1 scan0136 | |
| Specification for the gearboxes of the first eight Spectre Chassis, listing various components and their part numbers. | 7th Jun 1935 | Box 94 \ 1 scan0137 | |
| Parts list for various motion shafts and drive systems. | 7th Jun 1935 | Box 94 \ 1 scan0138 | |
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