Anyone know if its even possible to replace the OEM 6HP26 trans with a 6HP28? I understand they are both physically identical, so a 6HP28 should just drop in, but what about all the programming and mapping?
There's a couple of reasons I want to do this:
1) Shifts on the 6HP28 are a LOT smoother
2) More max hp/torque headroom. the 6HP26 is rated for only 443lbf.ft max, car is already making 420, and I've been thinking about a twin screw upgrade and several other performance mods that will take me at least into the high 500's.

 

There are some who have manage considerably more torque on the 26, there are also a number of aftermarket torque convertors available. I do not think the 28 will work because as far as I know, the TCM/TCU is completely different.

 

Guessing that some of the harsher shifting was smoothed (mapped) out with the newer TCM??

 

Probably not helpful as I have no idea about compatibility, but, I think if anything you'd want to go straight for an 8HP as it can do what you're asking. If you're going to go through the trouble to replace a transmission at all you might as well go all out. It can be found in the F-Type.

 

I'm I'm pushing over 500 on 08 Xkr And at least that much in torque if not more, And my shifts are butter smooth . You might just need a transmission adaptation procedure done

 

Keep your current tranny and ensure it has had the required ZF fluid/filter changes (IIRC 50k miles then ever 30k)

Do a hard reset after the tranny service or else buy something like a DTUK tranmission flash and you can reset the TCU whenever you want

 

You could also look into swapping in some of the 6R80 parts to upgrade your current transmission, like the Aussie guys/gals regularly do