Gearbox

technical data -

Four-speed Wilson epicyclic self-changing with preselector, using 4 pints of SAE 30 oil.<

The overall gear ratios with the spiral bevel final reduction are:

• top gear - 5 to 1
• third - 7.55 to 1
• second - 11.65 to 1
• first - 21.4 to 1
• reverse - 31.15 to 1

Gear change rod with 2x Amal joints (type 94/136).

Gearbox mounting is Metalastik part #31/128.

maintenance -

Drain and refill every 6,000 miles.

problems -

Gears may fail to engage if gear change pedal travel is too short (caused by maladjusted linkage or damage to Amal joints of linkage).

The gear change pedal will not return to the same position after changing between gears - this is perfectly normal.

Gears may appear to change correctly but be over or under compensated, due to the self-adjusting nut mechanism not working - to check this, note how the self adjuster spring is fitted (compare it with the others) then remove it. Ensure that the gear is NOT engaged, then use a pair of pliers to screw in the circular self-adjusting nut, taking care not to scratch the area where the spring locates. At the first half turn and each full turn after that, test the gear to see if the adjuster cams/levers still hit the square head of the adjuster screw. When the cams/levers just touch it gently, the gear is correctly adjusted. If they do not touch it at all, you have over-adjusted the gears and need to back the nut off a little.

Gears may appear to change correctly but have no effect, due to broken or badly worn gear brake bands. In this instance, adjustment as described above will lead to the adjuster nut screwing right down and the cams/levers still hitting the head of the adjuster screw. This will be obvious, because there will be a lot of thread protruding through the center of the adjuster nut.

Slipping of brake bands can be corrected by selecting each gear in turn and 'pumping' the gear change pedal about ten times. See also notes below.

The gear change pedal may, on occasion, spring up and no longer depress. This is a known problem with the Wilson pre-select gearbox and brute force (forcing it back down) is the correct solution.

removal -

To remove gearbox leaving engine in place, remove gearbox cowl and floorboards. Disconnect propeller shaft at both ends and remove. Jack up engine under rear of sump and detach rear mounting and cradle from chassis frame and gearbox. Disconnect pedal rod and selector linkage from gearbox levers. Take weight of gearbox and remove 11 setscrews round bell-housing flange (two top setscrews from rear, others from front). Detach starter motor, and rest it on exhaust pipe. Gearbox can then be drawn back and up through floor.

For a more discriptive instruction click here for advice from Neil Sharpe (Thanks Neil)

For additional information click here for advice from Tom Riddell (Thanks Tom)

To dismantle gearbox remove large top cover and side cover with selector camshaft and followers. Unhook spring from top gear adjuster nut and slacken nut right off. Detach small top cover and remove busbar spring. (Take two long setscrews right out, and slacken others evenly, releasing spring pressure on cover.) Take out rear cover setscrews and extract mainshaft, rear cover and ball bearings by tapping flange. Draw flange, bearing and speedo drive worm off shaft. Remove bell-housing setscrews. Insert mainshaft and drive out running gear and bell-housing assembly to front. Reverse gear drum will stay in box with centre ball bearing, and can be tapped out to front. Running gear components—drums and epicyclic trains—can be picked off until only primary shaft and top gear operating ring and clutch assembly are left on bell-housing. Unscrew nut on primary shaft inside bell-housing (locked by spring ring), and detach oil pump housing. Draw off oil thrower ring, plunger and eccentric (Woodruff key), and tap shaft out of front ball bearing with clutch plate assembly (riveted on). Brake band and busbar assembly mounted on bottom plate can then be removed from box.

To assemble gearbox place clutch thrust plate and ball thrust bearing on primary shaft, with return springs and plungers in clutch driving member. See that thrust ring is in top gear actuating ring so that it bears on thrust bearing, and that distance piece is against shoulder on shaft. Insert shaft into front bearing in bell-housing and assemble pump eccentric, plunger, oil thrower and pump body. Tighten nut, making sure that oil return thread is clear of pump body. Assemble running gear: 3rd gear drum on clutch plates, with bush, thrust washer, 2nd gear drum and 3rd gear planet assembly, 1st and 2nd gear sun wheel (larger pinion to front), thrust washer, 2nd gear planet assembly, 1st gear planet assembly, 1st gear drum, reverse planet assembly, reverse drum with centre bearing. Mount bellhousing assembly in vice, running gear upwards. Place packing ring on centre bearing outer race, and lower box, with bottom cover and brake assembly, on to running gear. Build up mainshaft with speedo drive gear, distance-piece, oil thrower, ball bearing, rear cover and driving flange. Insert assembly in box and secure rear cover. Insert busbar spring assembly, selector gear and side cover. Operate busbar several times in each gear to make up automatic adjustment. Fit top cover.

other notes -

Metalastik mounting #31/238 can apparently be modified by filing the holes to fit the original gearbox mounting dimensions. Metalastik mounting #M31-501 can apparently be modified in a similar way but also requires two new holes to be drilled in the center plate.

The E.N.V. type 75 gearbox was also fitted to the following vehicles:

• Riley 9.
• Lagonda Rapier.
• Crossley Regis 10/4 and 12/6.
• K series M.G.

It is believed the Daimler Light Fifteen gearbox is interchangeable.

Gearbox bearing equivalent part numbers :

When changing gearbox oil, it is advised to:
1) first run the engine for a short while to warm the oil and assist with draining.
2) Having drained the gearbox, refill with approx. 1.1/2 pints of paraffin and run the engine for several minutes without engaging any gear.
3) Switch engine off and allow contents to settle before draining - if particularly dirty it may be necessary to repeat step #2.
4) refill gearbox with the correct (SAE30) oil.

Viewing with top (gear) cover removed -
Note that viewing the gearbox with the top inspection cover removed allows checking for gear engagement and adjustment but gear pre-selection can only be viewed through the side cover.
Between each spring tensioned adjuster nut and square headed adjuster stop there should be a clear gap if the respective gear is not engaged and no gap if engaged. When engaged, the cam on the adjuster should move just sufficiently to tighten the self-wrapping spring around the circular nut (the clearance between the adjuster body, and the adjuster stop is approx. 1/4" at this point).

Note that engaging neutral actually partly engages both Reverse and 1^st gears.

When a gear (other than neutral) is engaged and the brakes are released, the car should not move on a level plane until the accelerator is pressed.

Viewing with side (selector) cover removed -
Access to the side cover is restricted but is made easier by removing the central bulkhead section. Unfortunately this is exceptionally difficult and requires removal of the front floor panels, the 10 securing bolts (the nuts are captive inside the engine-bay) and a countersunk screw above the propellor shaft.
Due to the shape of the bulkhead section, it may be necessary to apply some force, or bend parts of the adjacent bulkhead (removing the two lower, cupped, countersunk screws from the adjacent bulkhead will help) before the section will slide into the cabin. It is recommended that this approach only be taken if absolutely necessary.
Remove the outer screws from the selector hatch cover but not the castelated nuts or split pins. The lower nuts are below the oil level and the gearbox may need to be drained first. The cover, including lever arm, may now be gently eased from the gearbox, noting that there are 2 locating dowels (top left and bottom right).
Most of the selector mechanism can be seen attached to the inside of the cover, as the lever is moved, cams push struts out for each gear in turn (both reverse and first gear in the case of neutral).
Inside the gearbox, the vertical struts for gear engagement are seen - each gear may be tested by pressing the gear change pedal to the floor, then manually pressing the desired gear and holding it in place while releasing the pedal slowly. This results in the vertical strut being held in place and the gear engaging.

Additional notes on adjustment -
Removing top cover exposes the automatic adjusters for each brake band. The degree of automatic adjustment is governed by setting the adjuster stop screws on the brake bands. Excessive automatic adjustment may tend to reduce toggle action and cause slipping of brake bands.
Select the gear which is slipping and mark the adjuster nut with a pencil. Pump the gear pedal until the nut stops turning (it moves only slightly each time the pedal is moved). If the gear still slips the toggle action must be increased - unhook the spring round the adjuster nut, select and engage another gear, and unscrew the adjuster nut one turn (if special tool is not available use a 5/16" B.S.F. bolt and locknut). Unlock the adjuster stop screw, screw in half a turn and lock. Select and engage the gear which is being adjusted, refit the spring on the round nut, and pump the pedal until the nut stops turning.
When adjusting 1st or reverse gear engage 2nd, 3rd or top. Do not select neutral, as this partially engages both 1st and reverse. Interlock plungers prevent full engagement and thus hold all gears out.
Note that the top gear stop screw is not adjustable.
If automatic adjustment fails to secure the desired results the gearbox must be dismantled and the top gear plate clutch inspected.
If gear engagement is harsh, the toggle action must be decreased. Screw the stop screw out one full turn and pump the pedal until the nut stops turning.

Oil seal equivalent part numbers :

It should be possible to use a Payen part #NA207 (a 3/8" wide oilseal as used on the timing cover of the Reliant).

links -

Penrite recommend Gear Box Oil 30 for use in the LD10 gearbox (document kindly reproduced here with permission).
Web site addresses:
Global: www.penriteoil.com
Australia: www.penrite.com.au
UK/Europe: www.penrite.co.uk