I have a X350 Super V8 2004 with a gearbox fault.

Looking at replacement gearboxes, they all appear to be the same ZF 6HP-26 but they all appear to specify engine sizes, does this mean that the gearboxes are different? Specifically, will the gearbox from a non-supercharged car fit a supercharged car?

 

What is the nature of the fault that the gearbox must be replaced?

There can be differences in the bolt pattern for the torque converter housing.

 

While gear ratios are the same, the TCM and the torque converter are different between naturally aspirated and supercharged.

 

A few minutes into driving the car will go into limp mode, despite having oil changed and reflash.

Car is a high miler (160k miles) and I have decided that buying a reconditioned / 2nd hand box is the best option.

However, there are not many 4.2 super v8 boxes floating around, but plenty of boxes from the 3.5 V8, so would these fit in my car?

 

Once in safe mode the car will drive anywhere, even in high speed. So I assume the torque converter is ok and the problem lies within the box

 

According to my copy of the Jaguar Technical Notes 2003.5, the gearbox is the same, but the bell housing is different. The one for the V8s has cutaways to allow the exhaust catalysts to clear the bell housing. Clearly the notes do not cover the diesel cars as these weren't introduced until 2005/6

 

Would this mean that the gearbox from the 3.5l car would fit in my 4.2 as both cars are V8s?

 

As far as I know the smaller V8 is the same physical size as the 4.2, the stroke is smaller at 76.5 mm compared to the 90.3 of the 4.2. The block height may, of course differ. The only real way is to look at part numbers.


My notes say that the two V8s share the majority of engine components. They also say the gearbox is compatible with all engine applications.


Based on the notes, therefore, I would expect a 3.5 V8 box to fit the 4.2 V8. The V6 wasn't sold in the US so I don't think you have much of a problem, just making sure any used box you buy is OK.

 

-

 

If you are getting weird errors, is it still driving? I know of two cars where replacing coil packs resolved transmission faults. Strange and unlikely, but one case had a transmission rebuild, twice, by ZF, who finally changed 2 coil packs and resolved all shift issues.