Automatic Gearboxes

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We are able to supply the ZF4HP22 4 speed auto as used in the Range rover classic and the Disco I as well as the 4HP22EH and 4HP24EH used in the P38 Range rover and the Disco II. All our boxes come with a rebuilt torque converter which must be changed in conjunction with the autobox as they share the same oil circuit thus debris from a previous failure could contaminate a fresh autobox causing further problems if not changed.

Identifying your Unit

If you have a Defender, Disco 1 or Range Rover classic you have a 4HP22

If you have a Disco 2 or P38 Range Rover you have a 4HP22EH or 4HP24EH


How we rebuild them

When we rebuild a box, the unit is stripped down, washed in both Safety Kleen and hot wash tanks then the casings are shot blasted with glass bead, then painted. Once “Prepped” the stripped unit is sent to the build area in a plastic tub.

The autoboxes have a fixed set of new parts including friction plates, pump bush, filter, gaskets and seals, Once the parts are picked the first step in the build process is to lay the parts out on the bench for inspection, If they pass inspection they are used again, if not they go in the scrap bin.

Once the valve body is built it is put on our ‘Hydratest’ machine which cycles the valve body up to 100 start stop cycles to check all valves are operating correctly, it also checks all solenoids electronically to ensure they are also operating correctly. When the autobox is assembled we fit a test plate in place of the valve body and do a pressurised hydraulic leak test on all of the clutch packs to check they are correctly fitted and have no leaks.  These two checks with the Hydratest machine help us to identify and potential problems before the box is sent out.

Once built the unit is stamped with a number and a spec sheet filled out giving us info on the unit specification, who built it, when it was built and exactly what parts were fitted.

How to order

Should you wish to place an order for a unit you will need to first identify the serial number of the unit you want to replace using the videos to show where to find this number in the relevant section, you can then either use our online order form,  phone, fax or email us with your name, phone number, delivery address, what it is that you would like to order and payment details (please don’t email credit card details, use our secure online order form). Once the order is received we will contact you to give a delivery date and confirm carriage charges, your credid card will not be charged until you approve these costings.

When we send a unit out, we charge a core charge which is refunded upon receipt of the old unit assuming it is the same type as supplied and must be complete and not stripped with an intact casing, these core charges vary depending on the type supplied as detailed in the relevant section.


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