I have XHP on my e70. One of reasons i got it is try and mask the bushing wear on the e-clutch, as you can make it hold gears longer or down shift later etc .
I have no problems with my e53 transmission so I never bothered with getting it for the e53.
I found some pics of XHP on a e53 with the gear display enabled- top is Drive;
centre is in Neutral,
bottom is in Sports mode.

I'd have tried cheaper fluid before the ZF. Especially since they did not rebuild the valve body. Did they reset trans adaptations?

But to answer your second question. After servicing my 6hp26 with aftermarket seals, Valvoline Multi-Vehicle Synthetic ATF, and resetting trans adaptations, the 2-1 slam was gone immediately. And it was a severe slam, like getting hit from behind @ 10mph.

No haven't reset the tran adaptations. The advice from the transmission shop wasn't to do it. I do have INPA so have the ability to do it, main reason I haven't yet is I saw there is a lengthy re learn procedure so I would need to find the time and a suitable place to do that.

I contacted xhp flashtool to see what their product can offer. They said their software is built on the latest bmw software so if a bmw software update was to cure my issue then xhp should also do the same. The price was around $320Au for the license and 3 maps. I would probably only use the stage 1 map if I got it. I've been trying to find a good review of xhp with a diesel to see what it's like.

:popcorn:

I updated the transmission with ista-P on my e70 before I flashed it with XHP.

Maybe that wasn’t necessary if XHP are suggesting it updates it anyway.

I tried stage 1 for five minutes of driving and seemed no different to stock,
so I then flashed stage 2 and to me it was still pretty mild .
I’m on stage 3 now and in sports mode it shifts much faster but not harsh .
In normal mode even with stage 3 I don’t think anyone would really notice.

In sports mode with stage 3 as you slow it rev matches, which I think is dumb for a diesel.
There’s no way to disable that except by either just using stage 1 or 2 or just drive in normal mode .
There’s other options available to customize any of the stages -
lock out or enable 6th gear in sports mode;
Valet mode, drag race mode, and change when it upshifts and downshifts through the gears, rpm limit ,
and a few other options.

Thanks for insight into xhp. Do you happen to know if ista P can update the e53 transmission? I got ista D working all fine but haven't tried ista P. I researched doing the update via winkfp but was 100% sure on how to do it. Ista P I'm assuming is an easier process as it should identify the modules and their correct software rather than having to select it like in winkpf?

I don’t think you can update e53 transmission with ista-P.
Although ista-P is simple to navigate, it’s very limited in options. No choice which version you update to, and various modules all tied together. Also I used an ICOM to connect it to my e70 . Also must have big amp power supply.

WinKPF is what you need for e53, but I haven’t used it to update my e53.
Maybe because my e53 is an august 2006 build , it already had a later update version.

I took the leap of faith this morning and ran the software update for my transmission. After researching how to use WinFKP a bit more and understanding how it selects the software numbers after I select my gearbox I gave it a try and it worked. I charged up my battery overnight with the small ctek charger and left it connected. My battery is only a couple of months old and from my research the update takes 20-25 mins so I crossed my fingers and it held out. It is a tense 25 mins while its happening.
Did it solved the 2-1 harsh downshift? Almost, it does drive very nice now and i'm glad it is running to latest software for that model gearbox. It does seem to shift from 2-1 a little before it comes to a stop which makes it less pronounced. If I roll really slowly to a stop I can reproduce the 2-1 bump so hasn't cured it 100% but its less present. Having the fluid and seals changed has definitely made it much better to drive. It must have low on oil because it always used to have a strange shift from 1-2 when turning when cold, almost like it would fall out of gear for a second. This would only happen when cold and went away once it was up to temp. Since having the fluid and seals changed this has not happened again.

you need to do the relearn adavite reset follow the steps https://blog.fcpeuro.com/how-to-rese...daptations-zf6 look at Relearning Adaptations Table GS19 and Follow the steps after the reset take like 1 hr ish . then should relearn. where they got E90 change it for the E53 and be same steps less the relarn table

Thanks for the information. I would like to try this, just need to find a suitable location to do it.
Have you tried it and if so what were the results like? I keep reading conflicting views on resetting them so it's hard to know what the go is.