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Rebuilding a DB2 to MkIII gearbox looks easy at 1st but the more you fully study them the more complex they become & certainly aren't easy to rebuild properly, reliably & leakless.
If you look at the Aston Martin DB2 to DB MkIII Workshop manual under rebuilds for gearboxes there aren't any tolerances or measurements, especially how to make the synchro bronze cones work & get the gear pairs aligned, indeed the last paragraph in the WS Manual states 'each gearbox is reassembled in the reverse order of the operations enumerated' without any measuring of tolerances & settings !. A disaster waiting to happen.
For a long time Four Ashes rebuilt gearboxes with assembly 'as the workshop manual', then with the power of the engine being upped all the time & no development of the gearbox & after several breakages, Chris started to think that the tolerances as we found them whilst stripping & assembling were wrong, so using his knowledge of Manta A series, Classic Mini, MGB & some Ford gearboxes + a great many Workshop manuals & what Jack had taught him, he started to back calculate every gearbox tolerance.
With finding some very interesting documents about DB2 gearboxes, he found that he was exactly right so the 1st 10 or so gearboxes built under Chris's settings were more or less right, so now we know the correct laygear & gears (on mainshaft) endfloat & distances between gear synchro rings.
Since then Chris has gone further & obtained David Brown drawings, now the gearboxes need to be able to withstand 250 + hp, 230+ lbs ft of torque, more than twice the DB2 outputs - all gearboxes are built with a dedicated build procedure & some redesigned parts that are made to stop the gearboxes leaking oil, be more reliable & generally nicer to use.
Chris worked out in 2007 how to make the overdrive gearbox reliable for racing, rallying or just having fun on the road, this mod is incorporated into every overdrive gearbox rebuild, it's not used by other companies unless they have stripped one of our gearboxes !
Now New STD 3rd gear pairs are in stock, new mainshafts - overdrive in STD copper plated & Close Ratio Needle roller types are in stock - STD 4 speed with copper plated or Close Ratio roller type mainshafts are being made, 2nd gears will be made shortly. Laygears (Countershaft) are about to be made & good ones are being rebuilt with a welded on 1st gear, high strength bronze thrust washers are made now to stop excess wear on the layshaft with a laygear thrust washer to needle roller bearing conversion is about to be made, this reduces friction & heat.
We now have DB MkIII 'as original' overdrive gearbox kits ready for sale & DB2 - DB2/4 overdrive gearbox conversions will shortly ready for sale (expected sometime in 2016), all with Four Ashes legendary attention to detail.
Since then we have found our own colleagues & friends who can rebuild DB4 David Brown, DB5/6/S6 & V8 ZF gearboxes, DB5/ 6 & S6 BW Auto gearboxes and DB7 i6 Auto & Manual gearboxes.
see Axle Rebuilds
see Engine Rebuilds