4HP20 problem

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mpetrishin
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Joined: 09 Jun 2017, 10:29
Location: Saint-Petersburg
My Cars: '98 Xantia X2 1,8 8v
'98 Xantia X2 3,0 24v v6
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4HP20 problem

Post by mpetrishin »

Hello! What is the difference in mechanical parts between 4HP20 gearboxes: 20HZ05 (Xantia v6) and 20HZ26 (C5 v6)? I try to find gear ratios of both and it seems to same.
I have Xantia V6 with 4HP20. Previous owner change broken original gearbox with new one from C5. Gearbox is working, shifting all gears, but after 3000 engine rpm on any gear it gone to fault mode (3th gear). I check it with Lexia and error is "Consistency of gear engaged". Seems like new gearbox have another gear ratios and AT ECU catch too big difference between input and output speeds.
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xantia_v6
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Re: 4HP20 problem

Post by xantia_v6 »

The problem is almost certainly that the final drive differential ratio is wrong. I have had exactly the same problems when a later (probably Peugeot 406) transmission was used as a source of parts to rebuild my Xantia transmission.

There is nothing you can do but find a Xantia transmission, or at least a Xantia differential to fit.

And welcome to the forum. It is rare that we get a genuine member from Russia
mpetrishin
Posts: 3
Joined: 09 Jun 2017, 10:29
Location: Saint-Petersburg
My Cars: '98 Xantia X2 1,8 8v
'98 Xantia X2 3,0 24v v6
x 1

Re: 4HP20 problem

Post by mpetrishin »

Aha! Thanks a lot. Gear is the same but differential ratio is another. Previous owner still storing broken gearbox from this Xantia. Probably I will get it and change differentials after some search of defects. Disassembling of gearbox will needed... brrrrrr.
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xantia_v6
Forum Admin Team
Posts: 9053
Joined: 09 Nov 2005, 22:03
Location: France or NewZealand
Lexia Available: Yes
My Cars: -
1997 Citroen Xantia V6 (France)
1999 Citroen XM V6 ES9 (France)
2011 Peugeot 308 CC THP 155 (NZ)
1975 Jaguar XJ-S pre-HE (NZ)
x 825

Re: 4HP20 problem

Post by xantia_v6 »

Have you seen Jim's guide at http://www.eastment.net/4hp20/4HP20rebuild.htm ?
I think that is mostly my transmission in the pictures.
I am sure he will be here soon to give some advice.
mpetrishin
Posts: 3
Joined: 09 Jun 2017, 10:29
Location: Saint-Petersburg
My Cars: '98 Xantia X2 1,8 8v
'98 Xantia X2 3,0 24v v6
x 1

Re: 4HP20 problem

Post by mpetrishin »

Yes I saw it, thanks.
Looks like not the differential is another. Here is some 2 gearwheels before the diff named "step-down torque". That is the difference! 61x66 Xantia and 59x68 C5. That's it?
Image
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