Unchartered Territory

SydneyRoverP6B

SydneyRoverP6B

Well-Known Member
Staff member
My Rover’s transmission has now entered unchartered territory. Previously, the best any of my transmissions had run for was 71,495 Miles (115,000km). That had been held by the rebuild that took place during April of 1996. The box received a partial upgrade at that time, and was filled with Dexron fluid. Over the next 11 years the box was serviced a couple of times, each time being refilled with new Dexron fluid.

After the 4.6 went in during June 2007, the writing was on the wall as the box started to have a hard time of it. I have never liked smooth soft shifts in a transmission, and these were particularly noticeable with the bigger engine. In an attempt to lighten the load so to speak, I syphoned off some 4 litres of the Dexron fluid at a time, replenishing it with type F. I carried out this procedure some 5 times, driving around so as to ensure a good heterogeneous mixture between fluid exchanges.

The shifts were noticeably firmer, but the shift duration remained essentially the same. Driving with kid gloves was not enough, and in June 2009 after some 18,000 Miles with type F fluid within, the box failed.

Upon inspection by the gent (now retired) who would rebuild it, the front band had been snapped and its associated servo damaged. He expressed surprise that the box had lasted as long as it did behind the 4.6, given the current, albeit partially upgraded spec that he found. I said that I didn't drive it hard, he replied, just as well!

The rebuilt box would retain the same rear upgraded band from 1996 as it remained in as new condition. Being aware of the engine that I was now running, he made a number of changes so as to improve the box. Not least of all would be very firm fast gear changes unlike anything I have ever experienced before. This was a massive improvement and one that I am extremely pleased by. There is a feeling of a very direct connection between engine rpm and road speed, with little in the way of wasted rpm.

So my current box now has just on 72,000 Miles covered since June 2009, and hopefully will see many more miles to come.

Ron
 
Well, if it blows you can upgrade to a ZF.

You were waiting for me to say that, weren't you Ron? :p
 
Hmm, how would you get on for a bell housing, flex plate, etc, Brenten? Remember, your ex-Land Rover ZF just bolts right on to the back of your V8 engine, with only the rear end posing any difficulty.
 
WarrenL wrote,...
Well, if it blows you can upgrade to a ZF.

You were waiting for me to say that, weren't you Ron? :p
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I am really hoping that it won't blow Warren. As for going down the ZF route, to be honest in my case with my Rover, I can't see it ever happening. I would not be doing it myself as I cannot have my Rover off the road for weeks and weeks, so the cost alone would be 3 or 4 times that of rebuilding my BW. With the mods that my box has now, it is as far removed from how you described your BW as it is possible to be.

rockdemon wrote,...
Here's to another 72 hopefully :)
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Me too Rich :)

billoddie wrote,...
I think a good choice down here would be a Turbo Hydro 700...plenty of them and probably an easier swap to boot. :)
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Very possibly Brenten.

WarrenL wrote,...
Hmm, how would you get on for a bell housing, flex plate, etc,
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There is a business in Melbourne that sports a vast array of adpater kits which includes interfacing the Rover V8 to GM Turbo and Powerglide transmissions.

Ron.
 
Hi Ron.
SydneyRoverP6B said:
There is a business in Melbourne that sports a vast array of adpater kits which includes interfacing the Rover V8 to GM Turbo and Powerglide transmissions.
Click to expand...
That was what I was thinking...plus I would imagine the box would be a lot cheaper to rebuild if required.
Just a thought...numbers would need to be crunched obviously if it ever was seriously considered.
 
Honestly guys, if you're being told that the ZF is way more expensive to rebuild than a BW35 or TH700, you need to seek another opinion. The ZF is not actually that complicated (as far as auto transmissions go) and all the parts required to overhaul it were roughly the same cost as what I've needed to purchase for the BW35 (which I'm rebuilding to sell). Having now stripped both types of box, neither set of internals frightens me more than the other. If I can do it, any monkey can. Of course, the ZF requires a custom cross member, but as I've shown in the ZF thread, it can be made to bolt to the existing tunnel brackets. You will also need a custom section of exhaust made to navigate past the ZF, but that's not a biggie. I can't comment specifically on the TH700, but the advantages of the ZF are as follows:

- Rover V8 bell housing, torque converter, flex plate, spacers etc all available from wreckers for beer money. No expensive custom bell housing required. You simply need to grind three fins back to allow the ZF bell housing to adequately clear the right hand front end of the transmission tunnel.
- An ex-Land Rover ZF is perfectly matched to the characteristics of the P6 V8 engine (change points, torque converter lock-up, etc).
- Land Rover flex plate directly replaces the P6 flex plate. You needn't so much as sniff at your starter motor throughout the conversion.
- Using the BMW rear end* creates a hybrid LR/BMW gearbox that fits perfectly in the transmission tunnel and requires no modification of the P6 prop shaft.
- A Jaguar XJ40 output yoke fits the BMW rear end (with a slight modification) and mates directly to the P6 prop shaft.
- The Land Rover inhibitor switch is perfect (and in just the right spot) for connecting to the P6 loom for inhibit/reversing lights. Simple re-termination required.
- The stock P6 selector operates the ZF without any problem. In my case I ditched the rods for a Jag XJ40 cable and made a small bracket for mounting the cable on the underside of the transmission tunnel.
- The throttle valve actuator is correctly positioned for mating to the P6B accelerator linkage (I used the original P6 cable with a custom bottom end to suit the ZF - cost me $25 to have modified).

The disadvantage of the ZF is the need to buy two, or at least obtain some non-LR parts to make up your rear end (tail housing, output shaft and parking pawl arm). You also need a means of operating your speedo (the Dakota Digital ECD-100 is discussed elsewhere). An alternative is to use a Sherpa/LDV ZF, but that is about 90mm longer than the LR/BMW hybrid with resulting consequences for the rear mounts and prop shaft.

Anyway, that's my little patter done!

*A Jaguar XJ40 box as the second donor box might be just as suitable, but I haven't seen one in the flesh, and it's possible (from pictures) that the rear housing is longer than the BMW one, causing trouble with the prop shaft. Hopefully somebody here will provide some more concrete data on that.
 
WarrenL wrote,...
Honestly guys, if you're being told that the ZF is way more expensive to rebuild than a BW35 or TH700, you need to seek another opinion
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Here in Australia Warren, you can buy a good second hand BW35 at the top end for around $100, or as low as $60. When my Tx was rebuilt in 2009, it cost me $800, and most of that would have been labour costs I expect. According to the Australian Land Rover Owner's Forum, rebuilding a ZF 4HP22 would set you back typically $3000 onwards. At roughly 4 times the price, would it deliver 4 times the distance, probably not.

If I was still running the original engine, I don't deny that a transmission that readily changes gear may be more advantageous in terms of delivering more sporty performance. With the engine that I now have however, I don't need nor wish for a transmission that readily changes gears, indeed the 4.6 allows my Rover to accelerate quicker in top gear than my original engine would achieve in second.

It is a pity that we live in different countries, as if we lived close by we could see first hand what our Rovers are really like.

Ron.
 
I don't know what to make of those prices for a ZF rebuild, Ron. Somebody might be having somebody on. I guess it depends on what is included in that price, compared with what you had done to your BW in '09. One of the reasons I decided to plunge ahead with the ZF conversion was that the quotes/estimates I received for a ZF overhaul/rebuild were roughly the same as those for rebuilding my buggered BW (all were about the NZ$2K mark). As it happened, I did the ZF myself and it cost me the grand total of $220 in parts. I've spent $270 on everything needed for the BW, which will hopefully fetch me about $600 once I've pinned it back together. Not enough profit to cover the amount of work required, but I was keen to have a good poke around inside the BW after doing the ZF, so the value is other than monetary.

I'm known to pop across to Sydney every now and then, so next time I do I will be sure to chase you down, Ron. A comparison of the two cars would be very interesting indeed: we've gone down such different paths to achieve what we want from our P6Bs. Two cars that started out practically identical but have ended up rather different under the skin. I'd be almost certain to move to a 4.0 or 4.6 engine should mine give up, but it's such a sweet running low-mileage unit that I can't readily justify fixing what ain't broke. However I do read with interest any thread involving upgrades to the V8, and in the future it's quite likely that I'll carry out a modification or two to improve its output. Graeme (ghce) keeps trying to persuade me to put a Weber on it... Xmas is coming up, Graeme!

Meanwhile, I still haven't got over the novelty of those extra-low revs in 4th gear. It's a real "Yes!" moment every time I launch the old car down the motorway and it hits overdrive.
 
I can confirm what Ron says...and it comes down to the ZF being far far thinner on the ground her than the U.K. (woops...I should say NZ...so I guess I am a bit surprised as i thought ZF's wouldnt exactly be flush over there as well)
No way these things are lying about in wreckers yards...TH 700's on the other hand and pretty plentiful.
All things considered...its a number crunching exercise I think... :)
I can get an exchange BW65 with Ford internals for $750 off the shelf...and about $250-300 to fit...and it would be a "snappier" jobby than the present slurrer...but still stuck with 3 speeds.
In my old ZD Fairlane with a C4, I found it to be a very responsive and direct tranny...but it had 5 litres of Windsor motivation.
Thats sorta what I'd like with the Rove...a bit more "enthusiasm"...instead of "What?...Now?"
 
WarrenL said:
I don't know what to make of those prices for a ZF rebuild, Ron. Somebody might be having somebody on.
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Gotta remember, Euro cars are seen as a "premium" make here in Aus. Therefore any parts/labour for them through the usual auto trade has a fair margin on top.

ZF rebuild in Oz at a normal trans place would cost in the thousands easily.

A Turbo Hydro out of a VN Commodore would be my pick. Cheap, still around in wreckers yards and no computer to run it.
 
It's an interesting situation. As I said, the ZF isn't rocket science (as far as auto trannies go), so maybe you're right and it's a perception thing. The motor trade always charges what it thinks it can get away with. FFS, if I can rebuild one successfully without ever having opened up an auto transmission before I embarked on this project, then they're not exactly brain surgery. As for the availability of the ZF, New Zealand is awash in ex-Japan Land Rovers, Range Rovers and BMWs. Wreckers have 'em stacked high. Australia doesn't have the grey import trade we have, so I guess that would make them thinner on the ground. But it would pay to bear in mind that the ZF is damn near a bolt-in solution, but other transmissions are an unknown quantity.
 
WarrenL wrote,...
if I can rebuild one successfully without ever having opened up an auto transmission before I embarked on this project, then they're not exactly brain surgery
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The difference the way that I see it is in terms of how a transmission is rebuilt. Down the original as per factory spec or down the modified path. The latter requires additional skills and knowledge which I don't have. As I mentioned above, I don't like soft shifts, so knowing what needs to be done in order to correct that issue stems from experience I would say. The gent who rebuilt my Tx in 2009 was critical of who had rebuilt it previously, saying..."who ever built your Tx previously either didn't have access to a lathe, or couldn't be bothered to use one".

Ron.
 
You're right there, Ron. I simply put my ZF back together as per factory specs (not counting the different output shaft); modifying its behaviour would have been well beyond my capabilities. However, thanks to the baptism by fire caused by the LR valve body (which turns out to have been monkeyed with) I've started to gain a much better understanding of what goes on in that particular box of black magic.

Speaking generally, in my experience, the problems always begin when you hand your car over to so-called professionals who then go on to screw things up, or simply not quite do them properly. It has happened so often to me, and to people I know. You end up with a big bill and an indifferent outcome. That is why I've always done everything I possibly can, with my trusted friend John the only one engaged to carry out the tasks I can't manage. Even after 18 years, I'm still occasionally fixing things on Brown Rover that have been effed up by other people (the cross-threaded fuel pump inlet is a good recent example).
 
There are probably far more ZF enabled BMW's on NZ roads than Holdens by a long mile let alone the the rest of the ZF boxed Japanese imports and continental cars that abound in NZ, so its little wonder they are so cheap here though I am certain that there is a huge amount of price gouging when it comes to labour most esp with the ZF as they are as Warren has pointed out a bit of a doodle to overhaul regards to parts and labour time.

Graeme
 
Hi John,

That would be possible, but I imagine that the freight costs and charges wouldn't be cheap. Anyone who wanted to source one would I dare say be better off trying to locate one already here before going down the import path.

Ron.
 
I hate to think what the cost of freighting a gearbox to Oz would be. It would most likely be far more than the cost of the box itself. With the death of the Australian car industry a grey import trade might finally be allowed, but too late for you guys - we Kiwis have already got all the appropriate BMWs and Land Rovers. Maybe a grey import trade NZ-Aus? You can have all our old BMWs after our bogans have done with them.
 
I saw an advertisement in Unique Cars not long back...advertising the services of a company freighting automotive parts from N.Z to Aus...a complete motor was $500.
No price on a trans though.
 
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