Hey there Down Under - a quick pause for breath!!
First off the pictures of a ZF in a P6B are of my "English" car. Not taken by me, but the give away is the "Partsrange" logo which is RPi and the exhaust system, which I'd recognise anywhere! No there is no requirement to cut the tunnel about, apart from the obvious ammendments to the rear mounting. Yes we did take an angle grinder to the fins on the bellhousing to get a little more safety to the lower leading edge of the front bulkhead. I suppose if you were trying to convert a manual transmission car to auto that would recquire the shell to be modified, but no more than fitting a BW! The reference to modifying linkages is true as far as it goes, but nowhere near as alarming as it sounds! There is a lever on the bottom of the existing BW quadrant that provides the mechanical advantage to move the cable inner. It just needs the attachment point re-drilling in a different position. I haven't actually done that bit, as we reached that stage after the car was sidelined at Alan's. But there are now at least four or five that have been converted in the UK by Reg Mason's business. Also, don't get the comment about the output shaft and flange out of proportion. We used an LDV box and the output flange on that is the same as the BW so bolts straight up to the existing prop. The prop does require shortening though, around a couple of inches from memory, not a difficult job. The only other possible hazard i can think of is that this car is an early '68, so has the early type engine mounts. They make the engine sit slightly lower in the body than the more normal later ones. No huge drama if it did turn out to be a problem on a later car - just fit the early type mounts which are common with the P5B.
So why don't I know whether it has lock up on third then? Well this car only ran very briefly in this form and neevr got out of 2nd on its one run round the blocl (a very long story!).
I know you are very proud of your strengthened and improved BW, Ron; but the motivation fror the ZF isn't about strength, its about relaxed cruising. Sadly the BW would need a much taller final drive to achieve the same and that just isn't available. Plus of course, you get the lock up facility.
My Baby Rover has a ZF auto with the same characteristicsas the HP22, and the way it performs is a revalation after the P6's BW.
The notes on rebuilding a ZF are very interesting, Ron. The A clutch pack is clearly the ZF weak point. I had some guys buy my spare HP24 off me the other day who were fixing a P38 box. The A clutch pack on that had litterally split in two! That said, I have every reason to believe they are significantly more robust in use than the (UK version) BW. I hadn't clocked the Volvo use of these boxes before. So far I have spotted the following different tailshaft assemblies on cable control boxes - Volvo, BMW, Jaguar and LDV. Of these BMW and LDV have mechanical speedo drive outputs (I can't see one on the Volvo?) The other important difference between varieties is the valve block. The BW changes up (and down) on a combination of load and speed. The ZF minimum change points are set by speed alone (it will hang on to gears longer in response to heavy throttle, but it won't change up earlier in response to llight throttle), You could characterise it as an automated manual transmission where the BW is a true auto. For the Rover V8 it is therefore important to get the correct valve block so as to reduce the change up speeds as much as possible. This is only to be found in the Range Rover. The other usefull source material on ZF's is Wikipedia:
http://en.wikipedia.org/wiki/List_of_ZF_transmissions.
Be careful with that listing as it includes both cable control and electronic versions under the same category.
Chris
you are planning on a divorce soon