Final drive ZF 4HP20 exchanged with 4.7 ratio

Abdi · Post by **Abdi** » 06 Jul 2016, 08:40

We have Peugeot 605 with 2.0L XU10J2 engine & manual gearbox, the only version available in Indonesia, with final drive ratio 4.4. But the traffic jam is horrible in Bogor & Jakarta surrounded which obsess me to exchange with automatic gearbox ZF 4HP20 ex 406 but the final drive ratio only 3.73.

Is there any workshop could make the final drive with ratio at least 4.7 to have more acceleration faster in low rpm, the final drive gears NO need superb material because the car not used for racing purpose, only daily basis purpose.

My WhatsApp/WA number is +6281310554153 to have more faster chat.

Thank you.

Abdi Siregar
Bogor - Jakarta, Indonesia

Post by **xantia_v6** » 06 Jul 2016, 09:11

I am not an expert on the Peaugoet models, but I don't think that the ZF 4HP20 was ever fitted to the 2.0 engine, only the 2.2 and V6. The 2.0 I think had the Siemens AL4 transmission.

The V6 version of the 4HP20 had a higher final drive ratio.

You need to be aware that the 4HP20 transmission ECU will detect a wrong final drive ratio and go into limp mode. I have seen that happen when the final drive from a 2.2 transmission was accidentally fitted into a V6.

Abdi · Post by **Abdi** » 06 Jul 2016, 09:52

In Indonesia, 406 2.0L XU10J4 engine used ZF 4HP20 auto gearbox not AL4, AL4 used in 307 SW/Estate with EW10 engine where there are also less than 20 unit of 406 with EW10 engine but still using ZF 4HP20.

The 2.2L in 406 is the Hdi engine?

Abdi · Post by **Abdi** » 06 Jul 2016, 10:03

Other simple alternative gearbox for the peugeot 605 with XU10J2 engine is ZF 4HP14 auto gearbox where also used in 306 and 405

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Post by **CitroJim** » 06 Jul 2016, 12:09

xantia_v6 wrote: You need to be aware that the 4HP20 transmission ECU will detect a wrong final drive ratio and go into limp mode. I have seen that happen when the final drive from a 2.2 transmission was accidentally fitted into a V6.

So have I.

I was the guilty party

We live and learn!

spider · Post by **spider** » 06 Jul 2016, 14:09

Its interesting to read the ECU is actually interested in the diff ratio.

4.7 is very low

expect quite quick acceleration though.

Post by **CitroJim** » 06 Jul 2016, 15:03

spider wrote:Its interesting to read the ECU is actually interested in the diff ratio.

Oh yes, it's quite a clever ECU Andy...

It can also detect excessive slippage in the brakes/clutches by knowing the exact ratios and calculating the speeds it should see as a result...

Abdi · Post by **Abdi** » 07 Jul 2016, 12:38

So, what is the main function the ECU of the ZF 4HP20? Is it only monitoring or furthermore send signal to engine ECU to do something, such as recorded of driver driving style and instruct the ECU engine to follow?

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Post by **CitroJim** » 07 Jul 2016, 13:10

Abdi wrote:So, what is the main function the ECU of the ZF 4HP20? Is it only monitoring or furthermore send signal to engine ECU to do something, such as recorded of driver driving style and instruct the ECU engine to follow?

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The ECU does far, far more than that. It controls the entire gearbox and controls too the power delivery from the engine..

It takes all the decisions as to what gear should be selected for the prevailing conditions and also learns how you drive and reacts accordingly. Finally it controls the sport mode and has protection should the gearbox become too hot.

Post by **xantia_v6** » 07 Jul 2016, 14:28

If you look about halfway down this page, there are links to some 4HP20 technical manuals that give an idea of how the transmission works and what the ECU does.

Abdi · Post by **Abdi** » 07 Jul 2016, 14:40

Is it possible to reprogram the gearbox ECU if we change the final drive gears or if its hardly to do, is better using 4HP14 which not conntrolled by ECU?

My objection is, whether used 4HP20 or 4HP14, the final drive should be exchange with higher ratio than 4.4, please inform where I could order the final drive by custom ratio in UK with economical cost, the material no need superb where will not used for racing purposes.

Thank you if someone could give their PIC names and email address, more than one workshop is better.

Post by **CitroJim** » 07 Jul 2016, 14:48

No, it is not possible to reprogram the ECU as far as I know.

The HP14 is certainly easier to make work in such a situation but you will loose a huge amount of the benefits of having the auto-adaptive HP20. Once you have driven with an HP20 the HP14 seems a very poor sort of gearbox...

The HP20 should 'learn' your needed driving style and make up for the lack of a very low final drive once it has learned...

Post by **white exec** » 07 Jul 2016, 17:51

Slightly smaller wheels?
No, no . . . I didn't just suggest that . . .

Post by **white exec** » 07 Jul 2016, 22:04

. . . Although lower profile tyres on the same rims might just achieve something - on decent roads, that is.

Abdi · Post by **Abdi** » 08 Jul 2016, 06:18

So, could anybody give references which workshops able to make final drive customized with our requirement with economic cost?

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Final drive ZF 4HP20 exchanged with 4.7 ratio

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