ATF change - how true is this?
Discussion
The chap asking about fluid change intervals reminded me of something I'd been meaning to ask on here...
When I was getting a quote from Lexus for some work, I asked about having the ATF changed. The response was "oh no, we don't recommend that as we've had a few people find their transmission develops faults soon afterwards".
That seemed a little odd to me. I've had ATF changes on previous cars and I know that this Lexus has had at least one ATF change before my ownership. I've never had a fault develop afterwards.
So thinking about the service manager's response I wondered if it might be one of two things:
1) People already have a faulty gearbox and try an ATF change as it is cheaper than a rebuild, then when it doesn't magically fix the problem (or it gets worse) they blame the fluid change
2) People have a trans with knackered clutches and bands, there is friction material in the fluid giving just enough bite to keep the gearbox borderline working, and when they have new ATF they lose this "bite" and everything starts clunking and slipping.
What do you think?
When I was getting a quote from Lexus for some work, I asked about having the ATF changed. The response was "oh no, we don't recommend that as we've had a few people find their transmission develops faults soon afterwards".
That seemed a little odd to me. I've had ATF changes on previous cars and I know that this Lexus has had at least one ATF change before my ownership. I've never had a fault develop afterwards.
So thinking about the service manager's response I wondered if it might be one of two things:
1) People already have a faulty gearbox and try an ATF change as it is cheaper than a rebuild, then when it doesn't magically fix the problem (or it gets worse) they blame the fluid change
2) People have a trans with knackered clutches and bands, there is friction material in the fluid giving just enough bite to keep the gearbox borderline working, and when they have new ATF they lose this "bite" and everything starts clunking and slipping.
What do you think?
I think people are either trying to save worn transmissions with new ATF and then the transmissions eventually do fail anyway despite new ATF, or else people are using the wrong type of ATF and knackering the clutches within the transmission. I can't see how a healthy transmission could be harmed by new fluid, especially if the pickup filter is replaced at the same time.
This applies to Toyota 4x4's but dare say the same applies to their car range.
Toyota used to have recommended auto transmission changes like all resposnible car makers, until around the mid noughties when they started using WS (world standard) synthetic oil in their transmissions, its really Dexron 6 full synth and on the better makes of Dexron 6 you will find Toyota WS is listed as compatible.
Those with WS oil don't have a specific change interval, instead its recommended the oil is checked periodically.
Most of us on the LC forums gave this suggestion a good ignoring and carried on as we've always done, changing the trans oil ourselves at sensible intervals.
Not as easy to either check the level or replace the oil now, the dipstick has vanished on later transmissions and its a case of removing the bottom level bung (without reading up you could easily remove the drain bung by mistake) with the trans at a certain temperature range, also instead of refilling via the dipstick tube as normal the oil filler is half way up the gearbox so you need some sort of pump to get the oil in, hence can be a messy job without workshop standard oil pumps...still DIYable though for the reasonably competent home mechanic.
Note those boxes requiring WS oil the filler cap has WS stamped on it.
Just out of intererest compare to my auto Forester which is 3 years newer, still has 3 dipsticks under the bonnet one of which serves as the level check and filler point for autobox, changing the autobox oil is actually easier and quicker than changing the engine oil, plus the transmission has its own spin on oil filter similar in appearance to the engine oil filter but works completely differently, straining only a small percentage of the oil continually where an engine filter strains all the oil passing through.
I've heard various warnings suggesting leaving very old oil in place, as above suggestions if the box has been left for 150k miles on its original oil maybe it isn't wise to disturb everything, not a quandry for me because never would i leave the oil in that long, trying to rescue a neglected transmission via a simple oil change strikes me as urinating in the wind.
Toyota used to have recommended auto transmission changes like all resposnible car makers, until around the mid noughties when they started using WS (world standard) synthetic oil in their transmissions, its really Dexron 6 full synth and on the better makes of Dexron 6 you will find Toyota WS is listed as compatible.
Those with WS oil don't have a specific change interval, instead its recommended the oil is checked periodically.
Most of us on the LC forums gave this suggestion a good ignoring and carried on as we've always done, changing the trans oil ourselves at sensible intervals.
Not as easy to either check the level or replace the oil now, the dipstick has vanished on later transmissions and its a case of removing the bottom level bung (without reading up you could easily remove the drain bung by mistake) with the trans at a certain temperature range, also instead of refilling via the dipstick tube as normal the oil filler is half way up the gearbox so you need some sort of pump to get the oil in, hence can be a messy job without workshop standard oil pumps...still DIYable though for the reasonably competent home mechanic.
Note those boxes requiring WS oil the filler cap has WS stamped on it.
Just out of intererest compare to my auto Forester which is 3 years newer, still has 3 dipsticks under the bonnet one of which serves as the level check and filler point for autobox, changing the autobox oil is actually easier and quicker than changing the engine oil, plus the transmission has its own spin on oil filter similar in appearance to the engine oil filter but works completely differently, straining only a small percentage of the oil continually where an engine filter strains all the oil passing through.
I've heard various warnings suggesting leaving very old oil in place, as above suggestions if the box has been left for 150k miles on its original oil maybe it isn't wise to disturb everything, not a quandry for me because never would i leave the oil in that long, trying to rescue a neglected transmission via a simple oil change strikes me as urinating in the wind.
From Ashcroft's website
"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."
https://ashcroft-transmissions.co.uk/product/zf4hp...
"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."
https://ashcroft-transmissions.co.uk/product/zf4hp...
paintman said:
From Ashcroft's website
"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."
https://ashcroft-transmissions.co.uk/product/zf4hp...
Hmmm, interesting. I've seen ATF change machines where the change is done with the engine running (and hence the fluid pumping), connected via the cooler lines. I wonder if an "engine on" ATF change, then a bit of a drive, then another one of those, then a bit of a drive and so-on would be the answer? Or if that would be no different to just replacing the filter? "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."
https://ashcroft-transmissions.co.uk/product/zf4hp...
donkmeister said:
Hmmm, interesting. I've seen ATF change machines where the change is done with the engine running (and hence the fluid pumping), connected via the cooler lines. I wonder if an "engine on" ATF change, then a bit of a drive, then another one of those, then a bit of a drive and so-on would be the answer? Or if that would be no different to just replacing the filter?
Did a bit of work on my own ZF4HP22 (Classic Range Rover) a few years ago to replace gaskets & seals as it was marking its territory just a bit too much.Under 100k on the box.
Stripped & checked the 'A' clutch for wear on the friction material on the multiple plates.
Little wear but what was apparent was the amount of very fine sludge deposits all over everything that I dismantled that I very carefully rinsed off with plenty of clutch & brake cleaner.
Also replaced the metal input shaft seals with the teflon ones as in this BMW link.
http://bmwe32.masscom.net/moswald/zf4hp22_rebuild/...
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