Through the
gearbox.
The solid gearbox block is replaced by a native hollow case, separate cover and rear extension. The input guide, input shaft, gear lever, output flange and two propeller-shaft joint references explain the connection from clutch housing to differential.
Case dimensions, hole patterns and installed stations remain estimates. Unscaled supplier photographs now correct the broad case/tail proportions; separately attributed catalog bearing envelopes are distinguished below. Millimeter units preserve scale consistently; they do not make these shapes measured reproductions. Owner photographs and the existing evidence remain available, but no fitted gearbox survey is asserted here.
Inspect the connections
Connect the mainshaft to the output flange
The long tail formerly contained only a plain shaft and hollow output flange. It now contains separate rear-bearing, seal, front-washer, smooth speedometer-wheel and flange-retention references. A stepped shaft tail, bearing/seal pockets and estimated housing shoulders connect those roles under the retained case and output planes. The narrow tail end remains clear of the existing propshaft bolt-head references; the larger bearing housing begins farther forward. Body, engine, clutch, propshaft and rear-mount poses stay fixed.
Factory plate81 lists 157732 rear bearing, 22G2353 extension seal, 155756 washer, 22G1752 six-tooth speedometer wheel, 155755 flange, WA116101 washer and 510618 nut. Rimmer supplies the bearing envelope: 7/8 inch bore, 2 inch outside diameter and 9/16 inch width (22.225 × 50.8 × 14.2875 mm). Those are catalog dimensions, not identification or measurement of the fitted bearing.
All axial positions, shaft steps, 26/31.4 mm outer tail radii, pockets, shoulders, radial drawing allowances, seal section and hardware profiles are estimates. The six-tooth role is deliberately smooth: no tooth mesh, driven pinion or cable connection is established. Nominal shaft/bearing contact does not establish a loaded fit; flange engagement has no modeled spline, thread or torque. Existing body/engine registration and clutch release gaps remain unresolved.
Housing omission and separation expose the relationships for inspection. They are not an extension-removal sequence or a verified seal/bearing replacement route. Propshaft release, flange retention, support, tunnel/tool access and applicable workshop procedures must be established before rehearsal can be trusted. No actual support strength, endfloat, seal compression, working speedometer or replacement feasibility is claimed.
The previously empty internal layout
Factory plates 80–82 distinguish the first-motion gear/shaft, mainshaft gears, two synchronizer assemblies, laygear and layshaft, reverse idler/spindle and two selector forks. Smooth estimated envelopes now represent those internal roles. The short case and long extension now replace the reversed proportions of the previous scaffold. Internal axial stations follow the new case partition; the exterior input shaft, output and lever/control axes retain their estimated stations.
Factory plate 82 distinguishes the 22G1408 fork shaft from the 22G2053 selector-control shaft. A separate support-shaft comparison and offset fork collars now replace the earlier incorrect direct attachment to the control rail. The support axis at X=55/Y=50.8 mm is a layout estimate; the operating connection, interlock and case retention remain unresolved.
The 104433 catalog bearing listing supplies 24.4 mm bore, 63.5 mm outside diameter and 19.1 mm width for the input and center bearing roles. Those are supplier comparison dimensions, not fitted measurements; the published bore is preserved as written. Shaft journals, bearing stations and all gear/fork geometry remain estimates.
The layout has no gear teeth/counts, helix, ratios, splines, synchronizer engagement, working interlock or loaded bearing fit. The former 25.0667 mm case/layshaft drawing mismatch is superseded by a shared estimated axis and shaft ends reaching the case planes. Front/rear layshaft passages and two bearing-support comparisons now show the relationship. Catalog bearing envelopes sit within estimated 31.95 mm-radius pockets and 42 mm-radius bosses, with 19.3 mm pocket depth and explicit drawing allowances. The revised case, cover and extension change their shape. Rear bearing, layshaft ends, gear/synchro/fork stations and selector seal follow the new shared construction layout; the front input gear, mainshaft/pilot and front bearing stay fixed. These are reference construction dimensions, not verified fitted bores, loaded seats, bearing retention or machining instructions. The internal-only study hides case/cover/body obstacles, while the case comparison shows the supports with the cover/body omitted for inspection, not because those parts can be removed in that order. General separation is illustrative and does not establish a disassembly, adjustment or replacement procedure.
Correcting the case and tail proportions
The RW Auto Classics 22G1553 listing photographs and Rimmer BHM5060R product photograph show a short main case and longer tapered rear extension. The earlier scaffold had those proportions reversed. Under the retained estimated input/output planes, the main-case/tail partition changes from 457.2/169.3333 mm to 260/366.5333 mm. This is an unscaled visual reconstruction, not a dimension extracted from perspective photographs or a factory drawing.
The donor listing does not identify the fitted casting on this car. Rimmer’s oil-seal-type unit is a comparison; the fitted scroll/rubber front-seal branch remains unselected. Existing owner IMG_6911/6915 shows underbody context without a calibrated gearbox envelope. The case/cover gains a narrower, lower ribbed main body; the rear case plane, center bearing, selector seal and internal axial spacing follow the revised layout. Input/output planes and lever/control axes remain the previous estimates.
Source-shape checks have been refreshed for the clutch, rear support and propshaft. The subsequent housing rear-web/gasket/four-fixing revision removes the earlier clutch-housing/boss/case overlaps in the reference shapes. The later open-fork/slave-entry revision removes housing/lever overlap; boot/rod overlap and engine/clutch frame disagreement remain, and the rear support now has paired extension-pad comparisons under revised estimated rubber axes; fitted mounting engagement remains unresolved. Neither a reduced overlap nor empty space proves actual-car fit, tool access or safe support.
What the factory plates establish
Factory parts plates 80–83 distinguish the main case, top cover, rear extension with selector turret, change lever and rear output flange. The lists include case 22G1553, cover 22G1884, change lever 22G2797 and output flange 155755. These are catalog identities, not identification of this car’s fitted castings.
Plate 145 distinguishes slip-joint and fixed-joint flange yokes, sleeve yoke and two GUJ101 journal references. It lists CHA336 from GAN6-154101. Actual shaft length, spline engagement and joint phase are unresolved. Early North American inhibitor-switch hardware is listed by chassis range; it is not assumed fitted or added to this study.
Drawing relationships and their limits
| Reference relationship | Basis and limits |
|---|---|
| Main case | Short ribbed body with rounded lower corners, open top and separate bearing/layshaft support comparisons. Estimated body 200 mm wide × 219 mm high × 260 mm long; top lip 220 mm wide and wall 6 mm. These are construction dimensions. Smooth internal roles are separately selectable; loaded fits and oil passages are unresolved. |
| Cover / extension | Separate selectable components expose the interior when isolated or hidden. The longer 366.5333 mm estimated extension has a tapered hollow shell and a hollow lever neck with shared selector/retainer-pin passages. The tail end uses estimated 26/20 mm outer/inner radii to leave the retained output hub and propeller-shaft fixing envelopes unobstructed in this drawing; these are not fitted clearances. Profiles, flange stations and cover thickness are estimated. Bolt counts do not establish surveyed hole positions; fixing hardware is omitted. |
| Output / propeller shaft | Estimated output and front joint flange faces coincide in this drawing. The four-hole 70 mm PCD is an estimate, not a machining or purchasing specification. The independent native propshaft study now supplies separate yokes, journals/caps/retainers, flange fixings and front sleeve/stub. The 70 mm pattern clocks45 degrees and front bores grow R4→R5.2; only the output mesh changes here. Old coarse joint meshes remain in this standalone export but are omitted from the combined viewer. A new estimated tube section and60 mm front cutback expose the slip boundary. Original output/differential stations remain unsurveyed. |
| Lever / gaiter / tunnel | The lever leans rearward above the extension. The single-rail controls study now supplies a separate rail/yoke/seat/lever/retainer and hollow outer gaiter with a curved flange, retainer and shared tunnel holes. All profiles, pose, maps, seals and installed clearances remain unverified. |
Input pilot reference
The external input keeps its old endpoint but now has an estimated 6 mm-radius,15 mm-long reduced tip, following the first-motion shaft role in factory plate80. It clears a separately sourced catalog pilot-bush comparison at the current engine export station. This does not identify the fitted shaft, establish running clearance or verify engagement. The clutch frame comparison records the remaining engine/bearing axial disagreement.
Use as a workshop study
Select the case and use Isolate to inspect its hollow construction. Select the cover, extension, lever, flange or either joint to follow that boundary into the whole-car surroundings. Existing clutch housing, release mechanism and rear support remain independent references.
General separation opens display groups. It is not a factory removal sequence, gearbox withdrawal trajectory, safe support arrangement, spline-disengagement distance or verified replacement procedure. Retaining the gaiter with the body is a display convention. Actual fastener access, tunnel aperture, exhaust and engine interference require a registered assembly and applicable workshop procedures before a removal rehearsal can be trusted.
Inspect the selector and body-gaiter chain. The earlier solid selector/boot source meshes are superseded; case/extension passages and neck are construction references, not fitted dimensions.