I have 4L80E /6 litre currently in my 1989. I used the EZY TCU controller. No issues at all but most of the aftermarket controllers cannot be configured for 12 cylinder. Fortunately the Marelli ignition 2x6 cylinder layout allows a work around for this limitation.
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Thanks for all the comments. I have confirmed that an O/d can go on a BW12 with some mods. Of the alternative gearbox suggestions, it would seem a TH400R with a Johnscars fitting kit would be the simplest and cheapest option that still provides a great alternative particularly with a lockup torque converter.
Reconditioned boxes are not cheap and vary greatly in price but I now know this is a better option than the old BW12.
Thanks for the input.
Garry
Has anyone fitted the manual 6 speed T56 or a later variation to their V12 Series 2 XJ?
If so what were issues that had to be overcome in the process?
Garry
There are a few folks who have put the T56/6060/Magnum onto a V12, but I think most are XJ-S people rather than saloon drivers. It seems far less common than the T5 and I think thatâs due to many of those box variants having excessively tall overdrives (both 5th and 6th are OD gears), and to make the shorter-overdrive boxes manageable youâd need the 4.09 diff ratio.
Just tossing this out for the heck of it. This outfit has been around sinceâŚforever.
One consideration with an add-on OD is whether or not there is actually enough physical space under the car to install it
Cheers
DD
If it helps your decision, a Gear Vendors overdrive is $3000+
They are basically the olâ Laycock de Normanville youâd get on an MGB (with some variation since they are no longer made in UK by GKN)
Mike, I have heard of such a thing! Kirby mentions it in book. He also says it was so seriously considered for production that a light in already in the instrument cluster.
I ran Jag O/Drive box on my series 1 XJ12 for 20 years with no issues. Not the slickest change going but handled the job.
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I have a jag 4spd +o/d in my v12. All jag parts (e-type bellhousing, rest xj6)
Sensational- looks and feels just right
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Almost anything is better than those boat anchorsâŚ
Well yes but to be fair the BW12 was a great box for its time and was better than many of its competitors - it is easy to be a bit critical through modern eyes.
Here is Australia we had our own car industry making Aust versions of US cars which many had old 2 speed transmission or even newer 3 speed stuff - I can remember driving a car with a TriMatic GM 3 speed and while accelerating wondering whether is was ever going to change to a higher gear. I can also remember driving my V12 etype with the BW12 and getting a thrill driving at higher than the speed limit in 1st gear - also when driving just above the speed limit in 3rd and flooring it and waiting for the kick down and the associated acceleration and induction roar.
I agree it is easy to be critical but we now live in different times but I like to drive my cars and a manual would be nice in my slightly improved XJ5.3C.
Hi Mike, I have a very early 1975 manual XJS that came with a story of it being an ex development car for an overdrive system. I have not been able to confirm this and I read your post with interest. Do you have any further information or memories of this S2 XJ12? Thanks, Nate.
Hi John, I am looking into overdrive systems on V12s as mine came with a story that it was potentially a development car for an overdrive system. Ive downloaded Kirbyâs book but I have not been able to find the part where it mentions overdrive was considered for production and is in the light cluster. I assume it is the XJS experience in a book? Kind regards, Nate.
Hi- I gave it a good hard look and cannot find where I read that! Sorry I cannot give further confirmation, but I swear it was in his book at one time. The book has been abridged over the years⌠I used to be mentioned in it, 25 years ago, recommending blue tinted headlights that faked HIDs. I was a teenager then, so it was a good idea at the time to look cool. Eventually Kirby took me out. My uncle too, he was mentioned for something like fog light kits but his contribution is gone too.
Take out your gauge cluster and see if the space for the overdrive light in your car is wired! I donât know which space it is, but if you shine a flashlight from behind youâll see one with gears I think.
Since you say your is a development car⌠is your car the dark one with the black horizontal louvers on the hood/bonnet, near the front? I saw this car about 20 years ago parked behind the Westminster MG Museum in Vermont. Then a few years ago Jaguar Enthusiast Magazine teased it for a next-month article on that car and then it never was published. Never got to hear about why it had those louvers.
Thanks for this John, I appreciate it. It is not the car you mention, we are located outside the US.
Hello Nate,
The only additional info I can share is the photos from the ebay advert that I can attach below:-
I wonder where it is now ? Hopefully others will chime in with further information.
Cheers,
Mike Badger
1973 DDS S1
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The development was not of a transmission-mounted overdrive; according to Paul Skilleter, who published âJaguar XJ-S, A Collectorâs Guideâ around the time XJ-S production ceased, the concept was a 2-speed final drive unit. This was around the time the vehicle was introduced. The instrument cluster had a space for an indicator, but was left blank according to his book.
Mr. Skilleter interviewed many of the Jaguar design staff and would know.
Mike BadgerâŚ. Thatâs an awesome photo you saved. That really looks like a Laycock overdrive mounted to a Jaguar differential. The four bolt holes on top are a give away that this should fit an XJ rear subframe. But there is more to it, both the diff and the overdrive seem to be special castings. Very very cool picture. -John
The Jaguar IRS is already front heavy. Imagine the constant twisting force the cage mounts must be under if this additional weight is bolted to the front of the cage. I wonder whether itâd even fit into the transmission tunnel.
kind regards
Marek