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Discussion Starter · #1 ·
The original automatic transmission in the 156 2.5 v6 Q-system is only a 4-speed. It could really do with 6 speeds for such an engine. I appreciate that the original Aisin unit is very reliable and few faults have been reported. Methinks Alfa were over compensating!

Does anybody know of anyone doing an autobox upgrade? If so, what unit was used? Is it possible to use ANY auto box?
 

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unlikely I'd think. Perhaps the box & ecu from the 166 might, but personally I wouldn't a they ain't likely to last as well, not to mention the crazy cost of renewing the fluid...
 
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Discussion Starter · #3 ·
Really? A gearbox upgrade can't be that uncommon can it? Why would the gearbox oil be so expensive to change.
 

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Isn't the 166's box a 4 speed as well? Or did they do a 5 speed?

Only other box that'll "bolt right in there" is the 6 speed manual, but it'd be way cheaper and 1000 times easier to sell your car buy a 156 V6 manual.
 

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Isn't the 166's box a 4 speed as well?
The 166 V6 auto was also a 4-speed box, but a different 4-speed box, so no there is no point trying to use that!
 

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To be honest, a far simpler route would be to replace the very peaky 2.5v6 with the far more flexible 3.0v6.
 

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or just buy a different car with a better gearbox!
 
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Discussion Starter · #9 ·
The changing over won't be that difficult, there should be a box that would suit the area physically.
The major issue is getting it to work.
Drive shafts that the q-system use are unique to the car and torque converter... So you would need new shafts that actually fit the joints at best or hub of an alfa v6.
Major physical loom work to replace an ecu that is integrated with half the engine loom and abs ecu / sensors
Finally, you would need to get the new ecu to talk to your system to relay output information like speed, bear in mind, not every car just uses abs sensor input but also torque converter and final drive speeds... which of course will be totally different to the current car. So you would need a professional auto box ecu programmer to write a new eeprom to suit.

I don't even want to consider the cost of such a project but would guess it would be four times the value of the car.
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The closest thing I can think of is the 156 GTA selespeed system, clutchless manual that you would have the remotest chance of getting to work with the parts you have.
 

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just out of interest, was the JTD auto in the 166 4-speed..?
The Diesel 166 was never sold in the UK, but the info I read this morning says it is 5-speed.
 

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Really? A gearbox upgrade can't be that uncommon can it? Why would the gearbox oil be so expensive to change.
the box on the 166 was a ZF sealed-for-life type, 4HP20 IIRC, so yeah sorry it's a 4-speed too.

Fluid is horrendously expensive, correct fluid is around £450 for a full change and not a simple process. Of course the sealed for life bit omits mentioning the expected "life", other marques show failures around 68-120K miles. The smarts in the box may decide to drop you into limp mode if it thinks there's any issue with the fluid too. or hitting the 60K "service" interval etc., dealer reset unless there's ways to DIY now.

As Grahameo says, it won't be easy, and the other problem would be getting the ratio's set right for your engine which probably won't match up to any of the main marques you'd be sourcing a box complete from...
 
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Discussion Starter · #13 ·
There is that possibility.
It would involve trawling through European eBay sites to obtain a transmission drive train, ecu and shafts etc and the cost to get it all transported to the UK. But again.

Iirc the hubs and their respective spline holes are different between the 166 and 156 as is the length track of the shafts. The bottom wishbone ball joint position is different to so even if you could fit the hub carriers from a166, the geometry would make the car virtually undrivable.

In theory though and with precise cutting, balancing , sleeving and welding, you could use the 166 5 speed jtd auto box, inner drive shafts halves, joined to the 156 q system outer halves so using existing hubs, cv joints and existing suspension components.

The other complications are the ecu matching and loom with sensor patching.
You have to remember that the q system auto box ecu is integrated with throttle control, emission control and abs speed sensors and more importantly, to the engine ecu.

There is a world of difference between rev limitations between a V6 and a JTD. It's no good having rev limits, change up, change down response limits designed for a 5000 rpm limit and trying to use it in a 7000 rpm engine with a high power and torque band. So...

It would involve a custom ecu parameter set up assuming you can get the box and engine ecu to communicate initially together.

Tempting as it sounds to have an extra gear, the unforseen costs and issues would put me off right away from even contemplating it.

That's why I suggested the Gta selespeed system that is already matched to the engine characteristics, hub carriers etc., even better if you can buy a rear ended Gta selespeed and just swap all the front end engine, gearbox engine loom, subframe, suspension, brakes and then you can forget the hassle of the auto box ecu Integration.
 

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Common sense prevailed !... Still, its all educational.
 

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I always feel that six speeds in the manual V6 is generally over the top, its very rare that I ever use all of the gears - in the Uk at least 1st to 3rd and straight into sixth covers all but the most determinedly hooligan needs......what the car really should have is a much higher 6th, or a numerically lower final drive so that its cruising revs are dropped to a more economical level.

So the idea of having a six-speed auto baffles me ;)
 
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Discussion Starter · #17 ·
I agree mate.. the six speed manual I tend to hop gears... I never use 1st, or 6th.
But... If I really wanted to be lazy, a Q- system can do 0 to 145 mph in one gear (4th) in H mode.

The only other car I know that can do the same without stalling is an Aston Martin Vanquish V12:eek:
A bit if a party piece of the "Q" but I wouldn't recommend it on a regular basis or the torque converter won't be happy;)
 

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what the car really should have is a much higher 6th, or a numerically lower final drive so that its cruising revs are dropped to a more economical level.
I've got something to help with this, should hopefully be ready to fit in my GTA when the engine comes out for the upgrade manifolds.
 
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