Has anybody fitted a Toyota Supra auto box in a mk2 to replace a DG box? What’s involved? How easy or complicated is it?
Mike

 

That would be extremely complicated.
Converting from an automatic to a manual gearbox is simple particularly if it is all Jaguar parts. Been there; Done that
Converting from an auto to a Toyota Supra manual box is relatively simple as aftermarket manufactured bell housings and flywheels are available.
Dellow in Australia manufacture a wide range for that sort of conversion.
They also manufacture bell housings and instructions for auto-to-auto conversions, but their charts don't cover Jaguar to Toyota auto boxes.
Still, it could be worthwhile to ask them
Cheers

 

Sounds like trouble to me. An extremely unusual conversion. But anything is possible if you throw enough money at it. Are the ratios vaguely right vs your present Mk2 rear axle vs a Supra axle?

 

I'm not at all familiar with the Supra box, but in theory it's doable. You would need an adapter plate between the block and bellhousing, a spacer on the crankshaft to space the flexplate the same distance as the adapter plate, machine the adapter plate for a starter, make a rear transmission mount and adapter to the drive (prop) shaft.

The DG has a series of rods and bell cranks to the transmission from the column shift lever, you would probably need to adapt to a cable ( assuming that's what the Supra has). Is the Supra a hydraulic or electronically controlled transmission? Electronic adds a layer of complexity. You'll also need to consider a speedometer cable and adapt to the transmission - is the Supra a mechanical speedometer output or electronic?

Finally, you need to consider the body; relative to most automatics the DG is both narrow and short. Most automatics are significantly bigger, so you might have to do metalwork to the body to make the Supra fit in the tunnel.

 

Good comment JB ~ as I said anything is doable if you throw money at it.

My good Dallas friend with his 43 car garage has a Borgward Isabella Coupe that was 4 cyl ~ pretty car. He found a new 6 cylinder Borgward engine still in its crate in Mexico of all places (Borgward did some assembly in Mexico). A new tunnel is required to fit this & many other mods.

One of his hired in prime mechanics (Polish) took 3 years & plenty of dollars to achieve an immaculate conversion to a pristine car (restored about 10 years ago.) If you did not know Isabella Coupe's well you would not know that it was not original right down to the carpeting. (Borward never made a 6 cyl Coupe) Swing axle had to be changed to accommodate the greater torque. And that's another story for another day. Bonnet even has a joint in it that you can see zero sign of.

He has subsequently fitted 1" larger diameter, wider wheels to it with wider tyres. New trims manufactured by hand to suite.

Original in same colour from internet (his has a red interior).








Rear sidelights spayed over chrome in this pic ???

 

Presumably, the adaptor plates used for the swap to Supra manual boxes would also match the automatics of the same generation. I think that would be the Aisin-Warner A43DL or A43DE (in Toyota speak - Aisin had their own designations), a 4 speed with lock-up and overdrive top. The E version is electronic control which makes fitting more complicated. If the control electronics is external to the gearbox, you have a chance of setting something up. If it's internal (like ZF), it's getting very difficult. It's probably a big advance on an old DG, but it's still 1980s and automatic transmissions have advanced a long way since then.

Considering the effort and cost, I'd replace the DG with a Toyota manual box, another 5-speed or an old Jaguar manual box.

 

If you are going to change the gearbox why not change the engine at the same time and put the straight six in from the Supra. Save you a lot of time trying to match the gearbox to the XK. You could even use the Supra's front wings and bonnet on the Mk2 so you know the engine will fit under the hood but they would need some fettling.

Sorry not very helpful but I don't understand why someone wants to alter an original Mk2 to a ******* car made of bits from around the world.

 

I'm not against modifying a Mk2 or the rest of the compact saloon family, but the modif should be in the spirit of the car, worth the effort in terms of cost/benefit, offering some fun, and preferably Jaguar based. For gearboxes, I don't find the original manual with overdrive, Moss or all synch, all that bad. I don't see any of the reasonable swaps apart from Toyota W58 or R154 as significant improvements. For automatics, I'd swap to a manual transmission or, if I had mega money, a Ford 6R80. Otherwise, stick with OE and make it work at its best.

Following from Cass, the X300 and X308 Jaguar XJs are absolutely wonderful cars, available at bargain prices (less than the gearbox swap), have all the better features that arrived in the 1980s and 90s, are in the old Jag tradition, and if maintained drive better in terms of ride-handling than (almost?) any car, Jaguar or other, that's appeared since.

 

I certainly like my X300, but also enjoy my '76 XJ6 with its later 4.2 engine. The Daimler is my shows car and gets lots of attention! AlecG.

 

It all depends on how you want to use your car. The DG wasn't stellar example of an automatic transmission, and it's now 75 year old technology. Axle ratios were also fairly low back in the day, my S Type came with the DG and a 3.77 axle. That means 3500-4000 rpm highway cruise and doing that on a 1,100 km drive makes a lot of noise and heat and burns a lot of fuel unnecessarily. Having an overdrive makes the car much more useable and less of an ordeal to drive. If you're only pottering over to the next village for a pub lunch that's a totally different situation.

I converted my car to a Ford T5, and that made a huge difference to the car. It nearly doubled my highway fuel economy for example. Heat was much less too, prior to the conversion on the highway the interior of the car in the summer could be 60°C inside, even at 110 km/h and all the windows down. The heat is less with the T5, but the car still gets very hot inside on a long drive.

If I was to do it again, I'd probably use a Ford 4R70W, simply because they are easy for me to get, are compact for their power capacity, have overdrive, and are easy to build a controller for. For those in Europe, I'd probably use a ZF 4HP22 from the XJ40. While the Ford 6R80 is a nice transmission, the controller is a problem. It's far more complicated than a typical 4 speed with overdrive.

 

Jagboi, in the UK there are 2 automatic conversions available, ZF4HP and Ford 6R80. The first is expensive, the second extreeeemly expensive. So much that I'd not take either, though I know from my XK that the 6R80 (it's a reworked ZF6HP) is a very nice gearbox.

 

I wasn't aware of the 6R80 conversion for an XK engine. Seems like a bit of overkill actually, give the power it can handle. My dad has a 6R80 in his Ford F350 Super Duty, and it's rated to tow a 15,000lb trailer for a GCWR of 22,500 lbs. His is the 6.2 petrol engine, the 6.7 diesel is rated for 33,000 lbs. Shifts very well and would be a nice transmission to have, but also not small.

I have only seen stand alone controllers listed as "under development" by the USA based aftermarket controller companies. I did look at doing one recently in conjunction with a friend who is doing a restomod on a Lincoln, and we decided it was too complex to DIY( and he's an Electrical Engineer - we've both done the Megasquirt EFI route on cars, so no stranger to electronics).

 

https://www.motorlegends.co.uk/6-spe...ic-conversion/

I think the 6R80 is the choice because it's good, takes an external controller, and they can ultimately fit it to many different engines - they started with the V12. It's better not to look at the price. From what I've read (zero personal experience), the set-up and tuning of a gearbox controller is a a very slow process. I guess that's why the modern automatics, like the ZF6HP in the XK are so good. Until I bought that car, I never thought an automatic could be as good as a manual; in fact it's way better.

 

That is expensive for sure! Here, I can buy a low miles used 6R80 from an F150 for under £500. I realize you're paying for the labour and the controller too.

 

Thank you all for your comments. Further enquiries brought to light an error in the article I read about using a Toyota ‘auto box’ as it was a manual box that was used. I’m now looking at either a ZF4 or xj6 / xj40 box. Any experiences anyone?
Mike

 

You might want to talk to G Whitehouse in the West Midlands. They do a conversion using a newer ZF transmission. Not cheap, but they have an excellent reputation.
B62 9JE

 

Thanks JB, I spoke to Don, grahams son, last week and it is in my thoughts. I’m just looking for a more cost effective solution if possible, but it is a very nice conversion.
Mike

 

Good choice. Graham's not cheap, but he's highly competent - you'll not find better. I've had parts for the old GM box in my Daimler from him.

 

Latest update on my thoughts for an alternative box. In conversation with a classic breaker who supplied us with some parts for the handbrake and accelerator assemblies, he suggested I look at fitting a 4 speed o/d manual gearbox as fitted to an s type he was about to break. Benefits are all the parts are available from the one vehicle, including pedal cluster, flywheel, clutch, overdrive switch etc. so this is now in my thoughts as it’s more cost effective and increases it’s desirability forthwith. Any thoughts guys, and has anybody who’s done it recently encountered any major problems?
Mike

 

I've not done the swap as my car started out 4 speed and overdrive. There are two gearboxes: Moss without synchromesh on first and the later all synchromesh. They are both very strong. The Moss box will be the cheaper, but most people prefer the later all synch. The two boxes have their own overdrives: A type and compact A type respectively. The later gearbox was also used on the series 1 and 2 XJ6 cars and in consequence is available in larger numbers. However, I'd go for a Mk2 or S type box. Apart from originality, they have sportier ratios. Also, I think their flywheel may be lighter than that of the later cars giving a livelier feel. It's simpler, or for some parts even essential, to have a matched set: overdrive, gearbox, bell housing, flywheel, starter motor. If the clutch isn't a diaphragm spring, it's straightforward to swap. The diaphragm is less demanding on leg muscles. Numbers: the Moss with overdrive are prefixed GBN and the all synch are JCN and JBN, if I remember correctly.

At least some of the 2.4 cars, certainly the 240, had gearboxes with different ratios from the 3.4 and 3.8. Also, the overdrives used different springs and oil pressures depending on engine size.

I'm sure others will add to and correct what I've written. It's also worth looking at some of the standard books such as Skilleter's Jaguar Saloon Cars.