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For those new members or those who have missed debate on the types of gearboxes used in the XJ8 and the supercharged variants here is a run down on the different models used in a 308

In the main mag last FEB and MARCH 2008 issues there was a two month article on both the boxes of the XJ8 and the Daimler/Jag supercharged models...........one, the XJ8 being a "sealed for life" ZF 5HP 24 type and the other Supercharged variant being the Mercedes W5A 580 type.

In the case of the ZF 5HP 24 box its supposed to be a sealed for life exchange unit but it can be serviced by people who know what they are doing..at aprox 60,000 miles.....it will take two people to refill the box....the stumbling block is the price of the fluid, the fluid is a non exchangeable non alternative brand ....you MUST use ESSO ATF LT71141 and no other.
The price of this oil is aprox £23.00 per litre at a main dealership
It takes aprox 7 and a half litres of oil but you have to do the proceedure twice as the converter cannot be drained at the sump. A very expensive job so its better to have it done at a geabox specialist or a Jaguar specialist.

The Mercedes W5A 580 type this is a "normal" gearbox oil and filter change using normal ATF fluid about 7LTRS and the Supercharged models are equipped with this type of gearbox.......hope this is a help...Joe

To the filling of the gearbox twice due to the converter not being able to change the oil form the sump.........this is now possible with the correct equipment..........for those members in the Bristol area.............
Bristol Transmission have a unit which changes all the oil in the box and converter at the same time. Most garages can only do the gearbox oil not that in the converter because they do not have the right equipment, hence having to double change the oil. These boxes are a specialist Transmission rebuilder/service item. Main Dealers do not like doing them because they do not have that correct equipment. Main Dealer, Hartwells in Bristol put their transmission work out to Bristol Transmissions for that very reason!
This could reduce the price of the job as a whole......anyone going to Bristol Transmissions and witnessing this procedure please let us know.
.......JOE

It is true that the correct Esso gearbox oil MUST be used in the ZF 5HP24(nomally aspirated XJ8/XK8) gearbox but now we do not have to pay the exorbitant Jaguar price for it.
Some of our independant Jag service agents now obtain this Esso oil in bulk and can sell it to us at £6-£7/litre and still make a profit.
The gearbox oil does NOT have to be changed twice each time to get a servicable result.
David Marks advises that the cost of the oil,but mainly the labour charge means that this is not cost effective for any extra perceived gain.
The recommendation is that these gearboxes should have an oil/filter & O ring change every 50k which should ensure(with normal use) the best available service life.About three litres of fluid will normally remain in the torque converter but the majority of the oil (7.25 Litres or so) can be drained out of the gearbox and replaced with new.
It has been suggested to me that if the gearbox service is first done at 30k and then at 30k intervals, there is then absolutely no need to be concerned about the residual oil in the torque converter at all.
It is interesting that Salisbury Transmissions have kit to get all the oil out at once,perhaps others will obtain similar equipment in time.
We are not dealing with exact science here, and judgement does come into the decision on what is the best course of action to follow.
In any event David Marks also advises that the ZF 5HP24 has a fatal design flaw which limits its service life to about 200kmiles at best.
This is the circlip arrangement at the front of the clutchpack which holds this in place on the shaft.
However well lubricated this is it will wear out eventually and they do.
It is a very common reason for terminal failure of these gearboxes.
It is also interesting that ZF are now offering their own factory reconditioned and guaranteed 5HP24 gearboxes,already filled with fluid and ready to fit in the car.