disco1 3.9 auto problem

[acid]

i have a 1994 disco 1 3.9 auto, can someone please tell why it wont change gear until the gear box oil is warm or i have done about 3mi at 15mph, after that it is perfect until it gets cold again, i have changed the oil but not the filter thanks Acid.

[micheal]

have you tried using the box as a manual change from 1 to 3 and then drive and see if that changes it is possible that the box could be knackered

[discool]

Not good news, this has been copied from Ashcroft's site.

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.

[acid]

thanks for the info, now iv got to find someone who nos how to clean a governor out, thanks again Acid