THE INFORMATION ABOVE IS TOTALLY INCORRECT
Dieselman wrote: ↑
Sun Mar 15, 2020 11:42 am
The correct ATF for the Zf-HP20 is any equivelant ofthe Total product listed below: Essensially Dexron 3 equivelant. PSA type 339 ATF.
Product line: Total FLUIDE G3
Manufacturer Release: 339 Typ V1,339 TypZ1, VT H55.633539 (G607), ZF TE-ML 04D, ZF TE-ML 14A, ZF TE-ML 17C, ZF TE-ML03D
Oil - manufacturer recommendation: Allison C-4, Dexron IIIG, Mercon, Volvo 97341
None of the above oils should ever go anywhere near a 4HP20 traansmission.
The only fluid for this transmission is ESSO/Mobil LT 71141
which is available from PSA under part number 9730.AE
The main reason reason that the 4HP20 is very sensitive to oil type is that it has a lock-up torque converter which (for smoothness) is often run with a 4% slippage. A Dextron fluid has the wrong friction coefficient and causes the lock-up clutch to wear, which eventually clogs the (effectively) non-replaceable oil filter to clog up, starving the transmission of fluid pressure, leading to a variety of secondary (often catastrophic) failures.
It is probably a good idea to change the transmission fluid (with LT 71141), but sadly this does not remove the particles which are already starting to block the filter, and the transmission will fail, usually somewhere between 150,000 and 300,000 km.
To change the transmission oil filter, the transmission must be removed from the car. On most models with this transmission, this requires also removing the engine, but I think (having removed and engine transmission from one of these) that there should be just enough clearance on an XM to split the transmission from the engine and lift it separately.
If you want an idea of what is inside the transmission, see CitroJims old site at: http://eastment.net/4hp20/4hp20_introduction.htm
(note the navigation is at the bottom right of the page).