Would like to hear your opinions on changing A/T fluid on the lifetime filled auto transmissions. I've read the UK and US forums and the board is divided on this topic. I'd like to keep my car forever. Would changing the fluid at 130000 km cause it to die a premature death? General consensus is to change it at 60-80,000 km or not at all.
Changing A/T fluid
- Thread starter jon2367
- Start date
Re: Changing A/T fluid
hi,
My previous e46 ride before I sold off was like 225 000km and my tranny was still running fine without changing the ATF since day 1. I kept the car for 7+ years.
At around 150 000 km mark, I came to the same situation whereby should I changed the ATF BUT decided to stay-on after some experience mechanic advices.
hope this help.
hi,
My previous e46 ride before I sold off was like 225 000km and my tranny was still running fine without changing the ATF since day 1. I kept the car for 7+ years.
At around 150 000 km mark, I came to the same situation whereby should I changed the ATF BUT decided to stay-on after some experience mechanic advices.
hope this help.
martmode8850
Well-Known Member
Re: Changing A/T fluid
i take yours is a E36... these trannies are built to last... probably longer life than the E46s and E90s... but there is a life span still...
the two schools are equally divided... no hard evidence either way..
i take yours is a E36... these trannies are built to last... probably longer life than the E46s and E90s... but there is a life span still...
the two schools are equally divided... no hard evidence either way..
Re: Changing A/T fluid
Thanks guys for your responses. Sorry for late reply- didn't know there was an update to this thread. I've recently received a 3rd opinion. He says at this age it is still a good idea to change the fluid. But due to the age of the fluid in the transmission, which by now should have aged to a fine vintage, he recommended changing only half of it. That should renew some of the worn out stuff in the fluid and perhaps delay the ultimate demise of the transmission. He used changing aquarium water as an analogy.
BTW my e36 is a manual. The A/T is in my wife's e46.
Thanks guys for your responses. Sorry for late reply- didn't know there was an update to this thread. I've recently received a 3rd opinion. He says at this age it is still a good idea to change the fluid. But due to the age of the fluid in the transmission, which by now should have aged to a fine vintage, he recommended changing only half of it. That should renew some of the worn out stuff in the fluid and perhaps delay the ultimate demise of the transmission. He used changing aquarium water as an analogy.
BTW my e36 is a manual. The A/T is in my wife's e46.
IntegraTypeS
Well-Known Member
Re: Changing A/T fluid
just to hitch on, my E90 325i reaching 110000k, no ATF change since day 1, was also pondering whether or not to change ... car drives fine, but dun dare to push nowadays...
just to hitch on, my E90 325i reaching 110000k, no ATF change since day 1, was also pondering whether or not to change ... car drives fine, but dun dare to push nowadays...
Red_Bean_Bun
Well-Known Member
Re: Changing A/T fluid
I changed mine at R2D. Car feels good. Also, changed my differential fluid as well.
I changed mine at R2D. Car feels good. Also, changed my differential fluid as well.
martmode8850
Well-Known Member
Re: Changing A/T fluid
well... i normally will ask myself, to who's advantage is the recommendation to. Especially when the manfacturer's directive is life-time fill.
And changing half??? Not very technical.
Aquarium water, or cooking oil, not the same thing, technically not as well.
It really is your call. If you feel better just to change it, be it half or all, then go ahead.
jon2367;576331 said:
well... i normally will ask myself, to who's advantage is the recommendation to. Especially when the manfacturer's directive is life-time fill.
And changing half??? Not very technical.
Aquarium water, or cooking oil, not the same thing, technically not as well.
It really is your call. If you feel better just to change it, be it half or all, then go ahead.
martmode8850
Well-Known Member
Re: Changing A/T fluid
this is a very good call. both the tranny and rear differential works with similar mechanisms and if you change one, better to change the other.
Red_Bean_Bun;576525 said:
this is a very good call. both the tranny and rear differential works with similar mechanisms and if you change one, better to change the other.
martmode8850
Well-Known Member
Re: Changing A/T fluid
you are right. manufacturers like GM and ZF have said life time fill. The newer trannies are built (with a life span) for low maintenance.
Redplanet;576636 said:
you are right. manufacturers like GM and ZF have said life time fill. The newer trannies are built (with a life span) for low maintenance.
R2D
Well-Known Member
Re: Changing A/T fluid
It not bits of metal in the oil. Those metal filings ground up by the gears get attracted by the magnets within the oil sump. Why half by half is to prevent oil shock caused by increased oil pressures. As ATF oil is used, it gets progressively thinner and when new oil comes in, the change in viscosity may shock the seals and cause oil leakage aground the main seal around the torque converter. It is best to just drain the oil pan the first time you change ATF. Subsequently after 40k KM of driving, you can drop the pan and change more oil. Typically, just draining the pan gets out 50% of the oil, if you drop the pan and sieve, its about 75-80% of the oil. There is no way to drain 100% of the oil.
BTW, the filter is actually a sieve cos the metal bits are already attracted by the magnets. It is the small pieces of friction linings that need to be trapped in case they fall off. These bits may end up in the valve body and jamming the solenoids.
It not bits of metal in the oil. Those metal filings ground up by the gears get attracted by the magnets within the oil sump. Why half by half is to prevent oil shock caused by increased oil pressures. As ATF oil is used, it gets progressively thinner and when new oil comes in, the change in viscosity may shock the seals and cause oil leakage aground the main seal around the torque converter. It is best to just drain the oil pan the first time you change ATF. Subsequently after 40k KM of driving, you can drop the pan and change more oil. Typically, just draining the pan gets out 50% of the oil, if you drop the pan and sieve, its about 75-80% of the oil. There is no way to drain 100% of the oil.
BTW, the filter is actually a sieve cos the metal bits are already attracted by the magnets. It is the small pieces of friction linings that need to be trapped in case they fall off. These bits may end up in the valve body and jamming the solenoids.
martmode8850
Well-Known Member
Re: Changing A/T fluid
good technical write-up Rod... certainly not found anywhere in the US/UK sites... need to patent this as no other expert had written in this kind of detail.
the seals are rubber? if they are, they will fail over time anyway. metal seals are the most reliable but expensive. what do you mean by shocking the seals?
also, i question renewing ATF as the manufacturers had not. Consiracy for us to change tranny earlier, maybe, but it must be calculated at a cost/benefit. Trannies nowadays are built for low maintanence, as shown by how difficult it is to renew ATF. Thus the data I am looking for is by renewing ATF, how much more mileage can I get out of the tranny before it eventually fails on me.
good technical write-up Rod... certainly not found anywhere in the US/UK sites... need to patent this as no other expert had written in this kind of detail.
the seals are rubber? if they are, they will fail over time anyway. metal seals are the most reliable but expensive. what do you mean by shocking the seals?
also, i question renewing ATF as the manufacturers had not. Consiracy for us to change tranny earlier, maybe, but it must be calculated at a cost/benefit. Trannies nowadays are built for low maintanence, as shown by how difficult it is to renew ATF. Thus the data I am looking for is by renewing ATF, how much more mileage can I get out of the tranny before it eventually fails on me.
R2D
Well-Known Member
Re: Changing A/T fluid
There is a nitrile rubber seal around the torque converter. This seal keeps the oil flowing back from the torque converter within the gearbox. ATF enters the torque converter through the center stator shaft under high pressure and there are 2 metal seals there. Once it runs through the torque converter, it exits in a ring around the stator shaft. So when the oil is older, its viscosity goes down and the ATF flows with less "resistance" on its way back to the sump. The biggest fear with changing ATF in older trannies is the possibility of busting this seal. With age, the seal starts to sag and as the oil does have the same flow pressures caused by thinning, it does not leak. When new oil is introduced, the viscosity suddenly goes up.
At the shop, with every ATF change, we pour in a bottle of Lubegard ATF protectant that has some seal conditioning chemials to keep the seals soft. This helps to prevent any failures in transmissions. There are also a shit load of large diameter O rings in the clutches within the tranny too but i have yet to see these fail as they predominantly work in oil and thus have super low wear rates.
As for oil change intervals, i practice 40k km between ATF changes. with this frequency, i just drain the sump and refresh the oil. I have seen cars run upwards of 250k km without failure so far. Its is hard to quantify the additional "mileage" new oil gives but personally a lot of it has to do with driving styles.
cheers
BTW, the ZF trannies are designed with a 100k KM service life and that is their MTBF. So all they ask of the oil is to last the same amount of time.
There is a nitrile rubber seal around the torque converter. This seal keeps the oil flowing back from the torque converter within the gearbox. ATF enters the torque converter through the center stator shaft under high pressure and there are 2 metal seals there. Once it runs through the torque converter, it exits in a ring around the stator shaft. So when the oil is older, its viscosity goes down and the ATF flows with less "resistance" on its way back to the sump. The biggest fear with changing ATF in older trannies is the possibility of busting this seal. With age, the seal starts to sag and as the oil does have the same flow pressures caused by thinning, it does not leak. When new oil is introduced, the viscosity suddenly goes up.
At the shop, with every ATF change, we pour in a bottle of Lubegard ATF protectant that has some seal conditioning chemials to keep the seals soft. This helps to prevent any failures in transmissions. There are also a shit load of large diameter O rings in the clutches within the tranny too but i have yet to see these fail as they predominantly work in oil and thus have super low wear rates.
As for oil change intervals, i practice 40k km between ATF changes. with this frequency, i just drain the sump and refresh the oil. I have seen cars run upwards of 250k km without failure so far. Its is hard to quantify the additional "mileage" new oil gives but personally a lot of it has to do with driving styles.
cheers
BTW, the ZF trannies are designed with a 100k KM service life and that is their MTBF. So all they ask of the oil is to last the same amount of time.
Thanks for the detailed explanation.
tsetse
Well-Known Member
Re: Changing A/T fluid
So you mean the ZF Gearboxes typically only last 100k km on average...thats pretty short life. So what do you recommend? I'm thinking of changing ATF once every 30k km as I just had my gearbox replaced a few months ago at a mileage of 82000km.
What do you recommend???
R2D;578176 said:
So you mean the ZF Gearboxes typically only last 100k km on average...thats pretty short life. So what do you recommend? I'm thinking of changing ATF once every 30k km as I just had my gearbox replaced a few months ago at a mileage of 82000km.
What do you recommend???
martmode8850
Well-Known Member
Re: Changing A/T fluid
ouch... about S$10k pain i believe if it is out of warranty.
btw, did you take the car since less than 50km? ie new from the showroom?
tsetse;579306 said:
ouch... about S$10k pain i believe if it is out of warranty.
btw, did you take the car since less than 50km? ie new from the showroom?
martmode8850
Well-Known Member
Re: Changing A/T fluid
good stuff and shows your technical competence. those sitting on the fence will want to change ATF.
let's go further.
the nitrile seal location. by the time Lubegard gets to it, we may effectively not cause a softening effect as we "hope" the mixture will get to it. With the protectent and ATF mixture, how are we so sure chemically it does not affect other components.
also, i believe newer trannies are filled with Dexron IV. the Lubegard site seems to have tested it with the older Dexron II or III.
R2D;578176 said:
good stuff and shows your technical competence. those sitting on the fence will want to change ATF.
let's go further.
the nitrile seal location. by the time Lubegard gets to it, we may effectively not cause a softening effect as we "hope" the mixture will get to it. With the protectent and ATF mixture, how are we so sure chemically it does not affect other components.
also, i believe newer trannies are filled with Dexron IV. the Lubegard site seems to have tested it with the older Dexron II or III.
