TD5 Defender Auto Kit
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Technical
Heavy Duty ZF autoboxes
We are able to supply the ZF4HP22 with optional strength upgrades depending what you are doing with the vehicle, what gearing, what engine Etc.
Stage 1 upgrade
We can build the 4HP22 but fit the centre section of the box with the bigger 4HP24 internals which upgrades one of the weak links being the C1/C2 one way clutch, the 24 one is much stronger.
another part which gets upgrade is the Planetry Gearset, the solid 24 type being much stronger,
Just the centre internals are changed so the box stays the same externally. This upgrade is an additional £ 250.
Stage 2 upgrade
The box can be built with both the 4HP24 internals as above but also the 24 front end as well giving you the added strength of having the larger 24 "A" clutch, also a weak point with the larger engines,
The fitting implications of doing this is the unit is 15mm longer. This upgrade is an additional £ 500.
Torque Converter Upgrades
The ZF auto as used in the Land Rover vehicles uses three different diameters of torque converter. Small. Medium and Large.
"Small" is used on the 300 Tdi, P38 diesel and the TD5.
"Medium" is used on the 3.9, 4.0 and the later 4.6 P38.
"Large" is used on the early 4.6 P38"s
Note the large converter can only be used with the stage 2 as it will only fit the 4HP24 front end.
A larger converter is desirable on a tuned engine for a few reasons :
1) Lower stall speed, there's little point in having a nice torquey engine if the converter is not transferring the drive and you are revving straight past it. A larger converter will reduce these revs and allow you to take up drive earlier which results in much more relaxed driving. This is by far the biggest advantage of upgrading the converter. Note these reduced revs are not to be confused with lower gear shift points, these stay the same as they are determined by the autobox ECU programming.
2) Less heat generation because of the lower stall speed and reduced 'slip'.
3) The converter has a lock up clutch inside and the smaller one struggles to cope with a stock engine, never mind a tuned one. This clutch can slip as you accelerate when it should be staying locked.
TD5's - The stock converter is the small one. If you have a stock engine, stick with the stock converter. If the engine has a mild tune then we would recommend upgrading to the medium diameter one, we have sold quite a lot and get very good feedback.
V8's - We would recommend the stage 2 and the large converter with a 4.6 or more. To fit the large converter you will need the 4.6 boss and flexplate assy to match the bigger converter.
2.8 TGV - We would recommend the stage 2 and the large converter with the 2.8 TGV, When using this setup be sure to order the correct conversion kit to suit the large converter. The part number for this kit from Motor and Diesel Engineering in the UK is Kit '82E'. See below for additional notes on the 2.8.
TD5 ZF upgrades
If you are converting your TD5 Defender to auto you have a few options, I though it may be useful to give some guidance based on our experience.
Stock 90/110, fine with a stock 4HP22 Medium Tuned 90, stock ZF, uprated converter Medium Tuned 110, stage 1 ZF, uprated converter Fully Tuned 90, stage 1 ZF, uprated converter Fully Tuned 110, stage 2 ZF, uprated converter Tuned Challenge 90, stage 2 ZF, uprated converter
Oil Temp Info
click here for a guide on oil temps
