Hi all. I'm currently shopping around for XK8 coupes and have been reading about the issues with the older 5-speed transmissions. Is it possible (within reason) to replace an older model's 5-spd with the later ZF 6-spd box? I apologize if this has already been addressd on this forum, but the sheer volume of information on here is a little overwhelming for a newcomer like me. I really appreciate any help, advice or pointing to other threads. Thanks in advance!

 

The ZF's are controlled electronically thru the TCM trying to get a new 6 speed to to talk to the modules for an older car can probably be done with enough time and money. The programs in the modules most likely will fight each other. If the concern is over the reliability of the 5 speed it would be cheaper to have it rebuilt and updated with a warranty then trying to swap it for an unknown 6 speed with electronic compatibility.
The ECM and the TCM communicate to control fuel, rpm, and gear selection.

 

In the end , it would be far cheaper to sell the old car and buy one with the 6 speed.

 

I meant to agree with the previous post concerning the electronics….tranny and engine swaps in cars with an old style CAN Bus are not for the expert mechanic, they are for the engineer that designed the thing. This swap project would become a never ending struggle between truth, justice and the American way!

 

Thanks. I was guessing there would likely be an electronic interfacing problem; but thought I'd ask the question just in case (being as both boxes are from the same manufacturer). Wishful thinking I guess. I'm just trying to get my head around whether or not to take the chance on an older (cheaper) 5 speed coupe or spend the extra $$ up front and go for a 6 spd model. I've never owned an XK8 or personally known an XK8 owner, so still doing my homework on these cars. Many thanks for the replies!

 

Or you could go with an early XKR with the Mercedes box.