Gearbox problem

[dswatts]

Just back from a 7000km camping holiday towing the camper trailer.
Last 500ks the auto started playing up, holding first and not wanting to change up and clunking into 2nd when it finally does. Not consistent as sometimes it changes smoothly. Also seems to clunk into 3rd.
Gear box was reconditioned about 100k ago. Car has 250k.
Gearbox had the fluid changed just before the trip.
Any ideas?

Thanks

Dylan

[PhilipA]

First place to look would be the MAF.
I know it seems strange to look at an air metering device to affect the Auto, but there you go. It's a Land Rover.
I think the advice is to disconnect the MAF and see if the auto behaves differently.
Regards Philip A

[Milton477]

Check the wiring plug on the passenger side of the gearbox. This is where the signals from the ECU go into the gearbox. Mine recently went into limp mode & this was the cause.

[dswatts]

No difference with the MAF disconnected.
Reset the adaptive values and still no change:(:(

[Slunnie]

You may find this an interesting read.

Ashcroft Transmissions (http://www.ashcroft-transmissions.co.uk/frequently-asked-questions/4hp22-faq-s.html)


I have a 4 speed ZF Auto and it sticks in first gear in the morning or when cold and is reluctant to change up from 1st gear. Once the gearbox has warmed up it shifts normally. Why?

The governor valve is sticking, which can be caused by contamination. i.e. clutch plates or other parts disintegrating. The fine debris finds its way past the filter and tends to accumulate in the governor, causing it to stick. A temporary solution is to remove and clean the governor. The problem will often recur as debris from damaged parts continues to build up in the governor. If the problem continues after cleaning the governor then it may be necessary it replace your Autobox.

We have noticed many customers reporting this fault starting a few days after an oil and filter change and after researching this using our experience and the expertise of others in the trade we have come to the conclusion that as ATF oil is a detergent type oil, when the oil is changed this will dislodge and stir up settled debris in the autobox which in turn jams the governor valve. In light of this although it sounds controversial it is debateable if changing the oil and filter is a good idea, some say if the box it going to fail it will fail if the oil is good or bad and their advice is leave it alone. I am still undecided but the truth is I get a lot of calls from customers thinking they are looking after the autobox by servicing it and a few days later this fault occurs.

[discorevy]

You may find this an interesting read.

Ashcroft Transmissions (http://www.ashcroft-transmissions.co.uk/frequently-asked-questions/4hp22-faq-s.html)

think that may be disco 1 box , as zf 4 hp22 eh ( disco 2 ) AFAIK is governed electronically.
what does it do when changing manually through the gears?

[dswatts]

think that may be disco 1 box , as zf 4 hp22 eh ( disco 2 ) AFAIK is governed electronically.
what does it do when changing manually through the gears?

Makes no difference changing manually.
Thinking I'll change the fluid in the morning and see if that helps.

[discorevy]

Would be worthwhile dropping the pan to check for metal dust ,filter and o rings for blockage and cavitation

[Slunnie]

When mine did it, it was a rebuild job. The grit was from the auto running hot and then the internals started to break down and then the downhill spiral begins. This is made worse by hills and towing.

What I would recommend is getting to the ATF cooler, which is at the bottom of the radiator pack and in the middle where you cant access it and clean the fins out properly. If you 4WD it, then I would recommend an additional ATF cooler also which is not in the standard location. I highly recommend the one from Davis Performance Landys as it will also handle the high pressure from the ZF which many wont as it is strong and has multi-barbed high pressure fittings, not clamped hoses. I blew a few hoses off before the Davis Landys cooler and since fitting the cooler I've had no more transmission problems.