Retro fitting an overdrive gearbox
Discussion
It gets expensive.
Firstly you need a gear box with an overdrive unit, ie you can't fit an O/D unit to your existing gear box. Reconditioned units are almost always sold in exchange - else you pay a hefty premium.
The whole thing is longer so you need to buy a shorter drive shaft. You will also need a different bell housing. Lastly I seem to remember that the diff ratios are different for overdrive cars, so you'd have to contemplate getting the diff swapped as well.
Sorry its not better news !
Firstly you need a gear box with an overdrive unit, ie you can't fit an O/D unit to your existing gear box. Reconditioned units are almost always sold in exchange - else you pay a hefty premium.
The whole thing is longer so you need to buy a shorter drive shaft. You will also need a different bell housing. Lastly I seem to remember that the diff ratios are different for overdrive cars, so you'd have to contemplate getting the diff swapped as well.
Sorry its not better news !
For a Dolomite Sprint I had no trouble.
Assume you can obtain a gearbox and gearlever for the right price...
On a Dolly Sprint you need a 12 volt feed to actuate the overdrive. It has to operate on 3 and 4, because it cannot take the torque of 2nd. I wired mine up with a 2nd switch too which made it very pleasant in traffic.
On my Sprint the axle ratios were the same. The propshaft was the same. So in all it was a very easy swap and made a big difference to driveability.
I would investigate the parts required with a company such as Rimmer Bros.
Assume you can obtain a gearbox and gearlever for the right price...
On a Dolly Sprint you need a 12 volt feed to actuate the overdrive. It has to operate on 3 and 4, because it cannot take the torque of 2nd. I wired mine up with a 2nd switch too which made it very pleasant in traffic.
On my Sprint the axle ratios were the same. The propshaft was the same. So in all it was a very easy swap and made a big difference to driveability.
I would investigate the parts required with a company such as Rimmer Bros.
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