Defender Drive Train Questions

bankz5152 · Mar 3, 2016

Got a couple drive train questions about the Defender, specifically the gearbox and transfer box.

Currently have an Ashcroft gearbox with the higher ratio 5th gear (5% higher) would fitting a 1.2 transfer box make the 5th gear too high?

Also if fitting the 1.2 box does this change the low range ratios?

Out of interest would fitting the 1.2 box make 1st longer, as in be able to stay in 1st longer?

flat · Mar 3, 2016

The low ratios gears would stay the same.

With 1st in high in a 1.2 you will accelerate faster but also run out of the quicker.

5th gear will be good for cruising on the motorways at 80mph but you will likely need to change down to 4th for hills.

I have tried both boxes in a 90 now and prefer my 1.4 as an 'all rounder'

jamesmartin · Mar 3, 2016

flat said:
The low ratios gears would stay the same.

With 1st in high in a 1.2 you will accelerate faster but also run out of the quicker.

5th gear will be good for cruising on the motorways at 80mph but you will likely need to change down to 4th for hills.

I have tried both boxes in a 90 now and prefer my 1.4 as an 'all rounder'

1st would accelerate slower and achieve a higher road speed before it needed changing ,though for road use you shouldnt be in 1st for long anyhow

flat · Mar 4, 2016

jamesmartin said:
1st would accelerate slower and achieve a higher road speed before it needed changing ,though for road use you shouldnt be in 1st for long anyhow

Sorry your exactly right, I was thinking of the 1.6 box.

Apologies.

So basically the opposite of what I said oops

bankz5152 · Mar 4, 2016

Thanks for the replies. Based off that I think id rather keep my 1.4 box

Though would increasing 5th by 20% raise it too high?

Brown · Mar 4, 2016

I've not tried a 1.2 box but with my overdrive the revs are very low even at motorway speeds. In standard tune it means you've got very little acceleration at 60-70 mph and even gentle uphill stretches tend to slow you down. With your re-map you might have as bit more low speed grunt. So much depends on what you want the car to do. If you regularly drive to Scotland and back in the early hours of the morning on nice empty roads then the higher the better. On the other hand, pottering around in the South East up and down through the gears in heavy traffic then with a 1.2 box and a high 5th you'd very rarely have much use for top gear I'd guess.

bankz5152 · Mar 4, 2016

Thats pretty much what I thought, thanks. Trying to learn a bit more about the more complex sides of car 'building'

Defender Drive Train Questions

bankz5152

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flat

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jamesmartin

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flat

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bankz5152

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Brown

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bankz5152

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