1998 3.9 disco atf fluid/filter change

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bart2181

New Member
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395
Location
birmingham
well times come for a major,major big service,apart from needing a new camshaft,sunroof seals,swivelpin seals etc it feels like the gearbox is slipping gears,so before i take out a second mortgage for a new box i thought i,d change the atf fluid/filter the only problem is althought being fairly mechanicly minded(having done a camshaft change etc)i have,nt a clue where to start?is there any threads anywhere pointing me in the right direction?how difficult is it?what can go wrong?any help much appreciated cheers craig p.s have a good cold weekend
 
feel free bring your vehicle round to mine over the weekend and i'll do it all for you

or were you just expecting us to do the searching and reading for you ?
 
:)well for a start i don,t expect anyone to do any searching or anything else for that matter for me,but this is a free thread so anyone who,s willing to donate any input into my mission feel free and like i said much appreciated cheers.and by the way where abouts are you based?if your not too far weekend sound s good
 
[FONT=Verdana, Arial, Helvetica]"One thing to note[/FONT][FONT=Verdana, Arial, Helvetica] is that you will only be able to drain around 4 - 5 Litres when changing the Filter screen (4-5 Litres remains in the Torque Converter). [/FONT] [FONT=Verdana, Arial, Helvetica]Hence we recommend you change the filter, refill with fluid and drive the vehicle for 500 miles or so. Following this, drain the sump once again but ONLY using the drain plug, don’t remove the sump.[/FONT]
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[FONT=Verdana, Arial, Helvetica]Then refill with another 4-5 Litres of new ATF and you will have renewed 75% of the fluid, which is as much as reasonably possible during servicing. You won’t need to renew the filter and fluid again for another 24,000 miles."[/FONT]



... is there a reason to do the filter before draining the sump again? Wouldn't it be better to change the atf a few times first, then do it so the filter is fitted will all fresh atf? ('cause thats what I was gonna do until I read this!)







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Another thing to note, see the at the bottom of this which has been copied from the Ashcrofts Transmission 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."
 
Yeah, I've heard that- some mechanics are v.reluctant to change atf in case they have a customer coming back shouting "you wrecked my gearbox!". I guess if theres debri in the box it must be on its last legs anyway

I'm still gonna do it but I think I'll do the filter first, that way I won't run the risk of crud in the sump being dislodged.
 
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