Gearbox/Clutch Question

[Fool]

Hi everyone, I will try and keep this short.
Audi A5, 2011, 3.0TDI, 6 Speed Manual


Had clutch + flywheel replaced by Audi.
Audi said I also needed gearbox replaced (at £5,500 just for the box, no chance, car is worth less than that!)
Took gearbox away to recon, too much work. (LPD gearbox).
Transmission specialist recommended s/h gearbox, (diff code, KMU, I didn't realise the difference until Audi pointed it out) which Audi very kindly agreed to fit as part of the clutch replacement (but have not guaranteed gearbox, only clutch).

Clutch would not register as being pressed until well past its normal range of motion and car would not start unless foot pressed extremely hard on clutch. (Didn't have this issue until I had clutch replaced).
Audi have said this is caused by gearbox bell housing being larger on the KMU gearbox than it is on the LPD.
Clutch hydraulic system just popped in Audi's service centre as I went to start it to take away. (I'm assuming slave maxed out before master sensor registered it was in correct position, so further travel for master was needed which overpressurized the system).

I guess my question is, is this caused by the gearbox I've provided or something else? Improper bleeding etc...
If the bell housing was larger on the refit gearbox, surely the slave would have further to travel, meaning the sensor on the master would be registering as clutch pressed whilst in reality clutch wasn't fully engaged at slave end?

Any help appreciated, and if anyone happens to have diagrams of a KMU and LPD gearbox I would be super grateful, as I want to know that Audi are telling the truth about the issue being to do with the gearbox and not the work they have done on the clutch.



Thanks

 

[NHN]

Why did the box guy suggest the different box code, if the bell housing has to be specific size & this ultimately affects the tolerances etc then I could understand the issue, would need to see both boxes side by side to possibly understand the differences & how it could cause an issue like this, before pointing fingers.

Tbh devils advocate & I understand financial impact, but matching the box from the start should have been the right path to avoid compatibility issues, if there are infact any.

 

[Fool]

Why did the box guy suggest the different box code, if the bell housing has to be specific size & this ultimately affects the tolerances etc then I could understand the issue, would need to see both boxes side by side to possibly understand the differences & how it could cause an issue like this, before pointing fingers.

Tbh devils advocate & I understand financial impact, but matching the box from the start should have been the right path to avoid compatibility issues, if there are infact any.

He had the gearbox from my car in his workshop (transmission specialist not just a random bloke), and I sourced what I thought was the same box s/h, sent him the link to check it was correct and he okayed it. I don't think he actually checked they were the same box and was assuming I knew (I didn't, nor did I realise there were two different codes for my model, my mistake which I am now paying for!).

Absolutely understand Audi's position on this, in fact if I was Audi I'd have outright refused to fit the box. The fact that they didn't refuse and fitted the box as part of the clutch replacement settled any doubt in my mind that it would cause issues, as I assumed they would know if it would. I was mainly trying to ascertain if what they're saying has any truth to it with regards to bell housing causing the issue. They've given me a number of different explanations, which change often, as to how it's the gearbox causing this fault and none of them sounded close to truthful.

 

[andreimrru]

Hello! Did you manage to fix it? I have the same issue after changing my transmision, old gearbox was LPD changes with KMU now i have to press the clutch very hard to get it started. My concern is if the clutch disangages 100% when changing gears in this conditions. I m not sure if the clutch master cylinder replacement will fix it "i found some master cylinder that are for KMU tarans exclusive" or the clutch fork.