For help, advice and discussion about stuff not related to aviation. Play nice: no religion, no politics and no axe grinding please.
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By KingJames
#1565559
I saw the reliable in caps and took that as the single most important feature. Plus there might be recent evidence that the mpg and emissions of certain German cars is baloney, they know how to play the game not build solid cars IMO.
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By Paul_Sengupta
FLYER Club Member  FLYER Club Member
#1565564
Well...

I have two German ZF auto boxes, one attached to a BMW 740, the other to a Jaguar S type diesel.

The BMW one I've had problems with for years - on zero throttle slowing down between 50 and 40mph, it jerks and goes into limp mode, putting itself in 4th gear (it's a 5 speed). No one has ever figured out how to fix this on the gearbox itself, though I've found that upping the idle speed on the engine from about 400-500rpm to about 600rpm fixes it. The other problem is that this gearbox has plastic balls in the valve body which wear out. After 230k miles mine are wearing out. When the oil is hot, it takes about 2 seconds between putting the car in reverse and the gear actually engaging. I've bought a refurb kit for the valve body but you can just buy the balls on their own - it's the labour of fitting them that's the issue though! I'm not sure if the newer ones have different balls, I think they do.

The Jaguar is a 6 speed I think, and very smooth indeed. But...having done something like 140k miles, the car has a slight judder going up steep hills on a certain amount of throttle. On googling this, it seems to be a common problem, and is the torque converter steadily wearing out. The threads say a new torque converter isn't expensive - but again, the labour to fit one and new (expensive) gear box oil is the issue. I think I'll put up with the slight judder going up hills for a few years.
Last edited by Paul_Sengupta on Mon Oct 16, 2017 12:34 pm, edited 1 time in total.
By avtur3
FLYER Club Member  FLYER Club Member
#1565565
Quick question, but is there confusion here, or is just me, between Asian and Aisin ?

I thought that Aisin Seiki was a well regarded manfacturer of auto boxes, some of which were fitted in cars from Asia.
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By Ridders
FLYER Club Member  FLYER Club Member
#1565571
My jeep has a ZF 9 speed automatic. It’s certainly not as smooth or nice changing as the BMW auto I had previously.
It's interesting in how it actually works, it has a 'dog clutch' on it. 5th is 1:1 ratio. When driving it the shifts up 4-5 feel different and also on the power off rolling the downshift is interesting, almost like it disengages the gears for a while.
Detailed description here...


On the DSG systems I believe they are either wet clutch or dry clutch. Probably worth clarifying what system your experience is on, when describing it as they are different.
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By stevelup
FLYER Club Member  FLYER Club Member
#1565574
Ridders wrote:My jeep has a ZF 9 speed automatic. It’s certainly not as smooth or nice changing as the BMW auto I had previously.


A lot of this can be due to the software though. The Jag XF with identical ZF 8 speed box to the one BMW use does not shift anywhere near as nicely.
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By davey
#1565784
Thanks for the replies, I've seen mixed reports about the Dsg gearboxes, apparently they were subject to a recall a few years ago.

I hadn't thought about Volvo to be honest but looking around, some seem to have done almost intergalactic mileages, which I take to be a good sign....

Mercedes also seem to go on forever so worth a look.

Can't afford a Veyron....... :mrgreen: