Fitting a 200tdi to the series gearbox is the issue.. The torque is too great for the series gearbox. e.g, having the power to Pull up steep hills in top gear puts far to much stress through the gearbox. The low range gearing with 4.7 :1 axels will be much lower with a defender gearbox but its high range, will be similar as the series has an underdrive of 1.15:1 and 1.2:1 on the Defender.
The 3.5:1 diffs of the Defender give the higher gearing, but its the 3.5 axel ratios that'll blow the series gearboxes even quicker... There are plenty of people who've done this conversion to testify..
However, If you fitted the 200tdi engine with its gearbox and perm 4x4 transfer box, you'll have solved the main weak gearbox issue, Just Modify the chassis where needed to fit.
As it'll be perm 4WD, you'd need to keep Diff lock engaged but you can use with the series UJ front axel, provided you run with front FWH's disengaged., then you won't need CV joints in the front axel.
Fit a stronger 4 pinion Dana Salisbury rear axel and you wont break half shafts.
With 4.7:1 diffs you'll have even lower gearing, especially in Low Range (which is Nice), while feeling ungeared in high Range. Yet in top gear, with a 0.75:1 overdrive, the final drive ratios of the Series/Defender are very similar.
Juggle position of engine/ gearbox and modified Prop shaft lengths to suit would appear the most effective method..
So why not Keep the Defender Engine and box together.
The 3.5:1 diffs of the Defender give the higher gearing, but its the 3.5 axel ratios that'll blow the series gearboxes even quicker... There are plenty of people who've done this conversion to testify..
However, If you fitted the 200tdi engine with its gearbox and perm 4x4 transfer box, you'll have solved the main weak gearbox issue, Just Modify the chassis where needed to fit.
As it'll be perm 4WD, you'd need to keep Diff lock engaged but you can use with the series UJ front axel, provided you run with front FWH's disengaged., then you won't need CV joints in the front axel.
Fit a stronger 4 pinion Dana Salisbury rear axel and you wont break half shafts.
With 4.7:1 diffs you'll have even lower gearing, especially in Low Range (which is Nice), while feeling ungeared in high Range. Yet in top gear, with a 0.75:1 overdrive, the final drive ratios of the Series/Defender are very similar.
Juggle position of engine/ gearbox and modified Prop shaft lengths to suit would appear the most effective method..
So why not Keep the Defender Engine and box together.
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