Hi, I am from the mk2 section.I want to upgrade my bw auto box with a ZF 4speed. I understand that it was a type fitted to an XJ model!!!
Can any body confirm and provide more information please. If so I am hoping that the bell housing will fit my 3.8 etc
Barry

 

No, that won't fit straightaway. All xk engines came with BW gearboxes.
The ZF box was first used in the xj40 and xjs, with the AJ6 engine. This was a complete new engine. The bellhousings have nothing in common.

It is possible to combine a ZF box with the BW bellhousing, but that takes some effort.

What is the reason you want an extra gear? If you are after lower revs at cruising speed, I would rather change the diff.

 

As said above.

The boxes you ask are known as 4HP22 with non electric kickdown, so a cable like the BW35/65/66.

The 4HP24 is the same unit, for the sake of the question asked, with full electronic controls.

The first mentioned is in the XJ40 3.6ltr cars, and the 2nd is in the 4ltr cars. Not sure what the 3.2 XJ40's used, but my X300 3.2 has the 4HP22 trans.

BMW, Merc, and some others also used these transmission, but the bellhousing to block pattern would also be nowhere near the Jag layout.

Nothing is impossible, just your imagination, sense of adventure and humour.

 

Wilf, its not a case of an extra gear, its more being a bit long legged at the top end,beneficial for mpg noise etc etc.
baz