Changing ATF fluid
#1
02-11-2010, 12:30 AM
Changing ATF fluid
Hey guys, been reading the site for a little while. Just never registered until recently. Anyways, I got my G35 at 53k miles and it now has 61k on it.
I figured I should do some 60k maintenance on it now, which means changing fluids. I searched around and it seems there are different opinions on how to change your ATF fluid. It seems Nissan Matic J or S is the preferred fluid to use, and to just drain and refill rather than get a flush. But I recall reading that if your fluid is old, it can actually do damage to change it at that point. How can this be the case? If you have old fluid you shouldn't change it at all? I always thought it should be done every 15k miles or so.
I figured I should do some 60k maintenance on it now, which means changing fluids. I searched around and it seems there are different opinions on how to change your ATF fluid. It seems Nissan Matic J or S is the preferred fluid to use, and to just drain and refill rather than get a flush. But I recall reading that if your fluid is old, it can actually do damage to change it at that point. How can this be the case? If you have old fluid you shouldn't change it at all? I always thought it should be done every 15k miles or so.
#2
02-11-2010, 12:36 AM
#3
02-11-2010, 02:59 PM
The filter on our cars does not need to be changed. It is bad to completely flush your ATF fluid if the fluid is old. Over time the clutch material on the clutches inside the transmission will wear down and will be in the fluid. Since the clutch material is now in the fluid, the fluid is causing friction between the clutches, and removing this fluid will cause your transmission to slip.
#4
02-11-2010, 03:46 PM
The filter on our cars does not need to be changed. It is bad to completely flush your ATF fluid if the fluid is old. Over time the clutch material on the clutches inside the transmission will wear down and will be in the fluid. Since the clutch material is now in the fluid, the fluid is causing friction between the clutches, and removing this fluid will cause your transmission to slip.
#6
02-11-2010, 04:07 PM
#7
02-11-2010, 09:23 PM
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OK... it's a big mess... Here's the deal.
#1 A lot of what is "old" or not depends not only on the age, but also driving style. Someone who brake boosts and drag races is going to need to change their fluid way sooner then someone who drives it like a church-going grandma.
The main reason you need to be careful with older fluid is exactly what Canadian said. The transmission is "used" to the dirty fluid, it works well with it. If you are at this point.. it's not too late. Do a 1/3 or 1/2 change (yes that will be messy). You want to mix new and old fluid together, drive a couple thousand miles, and do the same thing again... this will be a bit more costly and a lot more time consuming, but will be cheaper then a new trans. You want to keep doing this 50% Matic S changes 3 - 4 times.
If you think you are boarder lined on the fluid, then do not flush it, just change it. You could even stop the draining when it looks to be getting low and then refill with new (like a 85-90% change).
If you have stuck with the schedule, and you know your fluid has been changed ever 30,000 miles, then go ahead and do a completely new change.
Personally... I would NEVER flush a trans... but that's just me. The 5AT is one place that doesn't need to be spotless to work correctly.
I have a VB, and am determined to never let my tranny fail with the stress I put on it... so I change my fluid every 15k... but I only have 30k miles too...
#1 A lot of what is "old" or not depends not only on the age, but also driving style. Someone who brake boosts and drag races is going to need to change their fluid way sooner then someone who drives it like a church-going grandma.
The main reason you need to be careful with older fluid is exactly what Canadian said. The transmission is "used" to the dirty fluid, it works well with it. If you are at this point.. it's not too late. Do a 1/3 or 1/2 change (yes that will be messy). You want to mix new and old fluid together, drive a couple thousand miles, and do the same thing again... this will be a bit more costly and a lot more time consuming, but will be cheaper then a new trans. You want to keep doing this 50% Matic S changes 3 - 4 times.
If you think you are boarder lined on the fluid, then do not flush it, just change it. You could even stop the draining when it looks to be getting low and then refill with new (like a 85-90% change).
If you have stuck with the schedule, and you know your fluid has been changed ever 30,000 miles, then go ahead and do a completely new change.
Personally... I would NEVER flush a trans... but that's just me. The 5AT is one place that doesn't need to be spotless to work correctly.
I have a VB, and am determined to never let my tranny fail with the stress I put on it... so I change my fluid every 15k... but I only have 30k miles too...
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#9
02-12-2010, 06:54 PM
I did a drain and fill and got out 4 qts (on ramps). I will do another drain and fill when I change my oil in about 3k miles so I am not introducing so much new fluid at once. From reading the service manual Nissan recommend replacing 30-50% (if I am reading right). 4 qts into 10.9 qts is about 36% so I am within the suggestion.
#10
02-12-2010, 07:31 PM
OK... it's a big mess... Here's the deal.
#1 A lot of what is "old" or not depends not only on the age, but also driving style. Someone who brake boosts and drag races is going to need to change their fluid way sooner then someone who drives it like a church-going grandma.
The main reason you need to be careful with older fluid is exactly what Canadian said. The transmission is "used" to the dirty fluid, it works well with it. If you are at this point.. it's not too late. Do a 1/3 or 1/2 change (yes that will be messy). You want to mix new and old fluid together, drive a couple thousand miles, and do the same thing again... this will be a bit more costly and a lot more time consuming, but will be cheaper then a new trans. You want to keep doing this 50% Matic S changes 3 - 4 times.
If you think you are boarder lined on the fluid, then do not flush it, just change it. You could even stop the draining when it looks to be getting low and then refill with new (like a 85-90% change).
If you have stuck with the schedule, and you know your fluid has been changed ever 30,000 miles, then go ahead and do a completely new change.
Personally... I would NEVER flush a trans... but that's just me. The 5AT is one place that doesn't need to be spotless to work correctly.
I have a VB, and am determined to never let my tranny fail with the stress I put on it... so I change my fluid every 15k... but I only have 30k miles too...
#1 A lot of what is "old" or not depends not only on the age, but also driving style. Someone who brake boosts and drag races is going to need to change their fluid way sooner then someone who drives it like a church-going grandma.
The main reason you need to be careful with older fluid is exactly what Canadian said. The transmission is "used" to the dirty fluid, it works well with it. If you are at this point.. it's not too late. Do a 1/3 or 1/2 change (yes that will be messy). You want to mix new and old fluid together, drive a couple thousand miles, and do the same thing again... this will be a bit more costly and a lot more time consuming, but will be cheaper then a new trans. You want to keep doing this 50% Matic S changes 3 - 4 times.
If you think you are boarder lined on the fluid, then do not flush it, just change it. You could even stop the draining when it looks to be getting low and then refill with new (like a 85-90% change).
If you have stuck with the schedule, and you know your fluid has been changed ever 30,000 miles, then go ahead and do a completely new change.
Personally... I would NEVER flush a trans... but that's just me. The 5AT is one place that doesn't need to be spotless to work correctly.
I have a VB, and am determined to never let my tranny fail with the stress I put on it... so I change my fluid every 15k... but I only have 30k miles too...
I had my tranny rebuilt last year, and I think I want to do a fluid change (3 track days and daily driven) soon. How much do you normally get out if you do a change? Just drain it out and when it stops, should I start to fill it up again? I've only changed my fluid once, which is when I rebuilt the tranny. I have probably 9-12k miles on the rebuild.
#11
02-13-2010, 06:44 PM
I'm in a similar position right now, so I need some info. I have a 5AT 04, car has 61K on it. Infiniti wants to charge an arm & leg to do the service. As far as you guys know, do they flush it or drain and refill without changing the filter? From when I did Auto tech training, they said to always change the filter when you change the fluid, but you guys are saying not to change the filter. what makes the filter on these transmissions any different than any other AT out there? If it is just a simple drain and refill then I'll do the work myself, but I need more hard evidence that this route is OK other than a few people's opinions
#12
02-13-2010, 07:50 PM
If they are changing the filter they have to drop the pan. That will be pretty expensive. Ask them what they are doing and if you feel comfortable with the cost, go for it. You can do like BythaBay did in his video series and put a filter in the cooler line. This would make the filter change easier, but you better make sure you regularly change it (30k) or it can become clogged and starve the trans.
#13
02-15-2010, 05:40 PM
#14
02-15-2010, 06:20 PM
Here's what I'd recommend assuming you're fluid hasn't been changed ever or hasn't been changed in a long time (40K+ miles).
1) On a COLD* engine, drain the tranny. Measure the amount that came out to the nearest 100ml and replace with the same amount. Use empty oil containers with 100ml graduations to get a drain measurement. *Tranny fluid expands 15% when hot so replacing with cold fluid can skew fluid levels.
2) Drive 100 miles or so and do the same drain/fill procedure.
3) Repeat the drain/fill procedure one more time.
4) Once completed, perform a single drain/fill every 15K miles.
Remember, heat is the leading killer of transmissions and much of the heat can be related to old ATF.
Replace with Nissan S-matic only. J-matic is no longer available. Do not use any other brand. No exceptions and I won't debate this.
From what I've seen of JATCO 5AT, the filter is technically not serviceable.
1) On a COLD* engine, drain the tranny. Measure the amount that came out to the nearest 100ml and replace with the same amount. Use empty oil containers with 100ml graduations to get a drain measurement. *Tranny fluid expands 15% when hot so replacing with cold fluid can skew fluid levels.
2) Drive 100 miles or so and do the same drain/fill procedure.
3) Repeat the drain/fill procedure one more time.
4) Once completed, perform a single drain/fill every 15K miles.
Remember, heat is the leading killer of transmissions and much of the heat can be related to old ATF.
Replace with Nissan S-matic only. J-matic is no longer available. Do not use any other brand. No exceptions and I won't debate this.
From what I've seen of JATCO 5AT, the filter is technically not serviceable.