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Transmission Fluid - Flush or change

33K views 12 replies 8 participants last post by  styls255 
#1 ·
I took my 2006 Mazda3 with 31,000 miles to the dealership for an oilchange and they recommended a transmission fluid flush. Should I really be looking at a full transmission fluid flush, or would it be ok to just change the transmission fluid?

i've heard some horror stories when it comes to flushing components like this but then again I'm not very knowledgable with cars so I thought this would be the place to ask!

Thanks
 
#2 ·
(imo) if the old fluid is really bad, it's better to flush (a drain and fill only replaces some of the fluid, as much of it is in the torque converter and lines.)
As far as dangers of flushing, most if not all dealer "flushes" are low pressure operations.
The preferred method simply taps into one the the tranny fluid lines are replaces old fluid with new fluid as the car is running, using the engines own pressure. As the engine feeds old fluid into the machine, it fills a diaphram that forces the same amount of new fluid into the return line. It's not a high pressure or dangerous procedure. I let my dealership perform a flush and see no adverse affects.

having said all that, most stealerships charge up to twice as much for a tranny flush as independent shops...so you might want to check other places unless you only want the dealer to work on your car. I negotiated a better deal when having all my 30K maintence done.

If you are still concerned about potential damage from flushing, but your fluid is in very bad condition, you can also do 2 or more drain and fills...to replace as much of the old stuff as possible.
 
#4 ·
[quote author=Flyersguy172 link=topic=128903.msg2758274#msg2758274 date=1227199871]
I took my 2006 Mazda3 with 31,000 miles to the dealership for an oilchange and they recommended a transmission fluid flush. Should I really be looking at a full transmission fluid flush, or would it be ok to just change the transmission fluid?

i've heard some horror stories when it comes to flushing components like this but then again I'm not very knowledgable with cars so I thought this would be the place to ask!

Thanks
[/quote]

go ahead and get the flush done. you have nothing to worry about. like John said, they use the cars pressure to push fluid through the cooler lines. most places nowadays, however, will send a tube through the actual transmission dipstick tube, and run a machine that will take small amounts of old fluid out, and put new fluid back in. thats the machine we use at my shop anyways, and I'm pretty sure most other places do this too, because there is less chance of error and liability (since your not tapping anything)

as far as fluid colors, don't go by that. i always say change it out whenever your manufacturer recommends, or earlier (like Daniel), but not after it gets discolored and funky smelling.

wild guess says you drive an automatic, but just in case, a manual transmission is a gearbox that needs to be drained and filled. a flush cannot be performed, and isn't necessary.
 
#5 ·
My 06 hatchback has 34,000 miles on it, so I'm in a same boat. I just called the dealership today and they said refill is recommended rather than flush, so I'll do the drain and refill. I will need about 5qt of Merc 5, and part dept. sell it at $4 per 1qt. My question is all I need is just drain the fluid and refill? I have an access to that machine that sucks from the dip stick. If I do that, how much fluid would I need? Using the machine will make a big difference or not? If not, I'll just drain and refill at home.
 
#6 ·
[quote author=06_mazda3 link=topic=128903.msg2759613#msg2759613 date=1227233217]
My 06 hatchback has 34,000 miles on it, so I'm in a same boat. I just called the dealership today and they said refill is recommended rather than flush, so I'll do the drain and refill. I will need about 5qt of Merc 5, and part dept. sell it at $4 per 1qt. My question is all I need is just drain the fluid and refill? I have an access to that machine that sucks from the dip stick. If I do that, how much fluid would I need? Using the machine will make a big difference or not? If not, I'll just drain and refill at home.
[/quote]

check the auto stores to see if you can find it cheaper.

if your going to drain it out, just measure how much comes out and replace the same amount. you can't go wrong that way.
 
#7 ·
[quote author=PJ 3i07 link=topic=128903.msg2760084#msg2760084 date=1227245433]
if your going to drain it out, just measure how much comes out and replace the same amount. you can't go wrong that way.
[/quote]

I can do that if I just drain it out, but problem is if I use machine to suck out more from dip stick hole, it's hard to measure how much came out. You dknow what I mean? I think I'll just do drain and refill at home.
 
#9 ·
[quote author=06_mazda3 link=topic=128903.msg2760668#msg2760668 date=1227282498]
[quote author=PJ 3i07 link=topic=128903.msg2760084#msg2760084 date=1227245433]
if your going to drain it out, just measure how much comes out and replace the same amount. you can't go wrong that way.
[/quote]

I can do that if I just drain it out, but problem is if I use machine to suck out more from dip stick hole, it's hard to measure how much came out. You dknow what I mean? I think I'll just do drain and refill at home.

[/quote]

true. what kind of machine is this (j.c.). most machines will tell you how much comes out.

if you are using something homemade, such as a pump and bucket, just put qt marks on the side of it.

[quote author=buddy_lee link=topic=128903.msg2760989#msg2760989 date=1227292096]
i've always been told that its ok to just change if you continue to change it every 30,000. and that you can wait till 60,000 but then you need to have it flushed.
[/quote]

people may say that.. but the manufacturer recommends a complete fluid exchange every 30,000 miles. I've noticed people around here will do just the drain and refill, but at earlier intervals (i.e. 20k or sooner)... if your gonna do it at 30,000 miles I'd do a complete flush with the filter kit. then again i'm pretty obsessive when it comes to my maintenance habits.
 
#10 ·
i do think it depends on the condition of the fluid. if it's still pink and feels/looks good, then a drain and fill is probably fine. if it's worn and black, a drain and fill will still leave 40%? of that crap in the system (although it will be diluted with the new fluid). crap is crap.
 
#11 ·
I did my own flush using the 1qt a time method, it was a little messy but at the end a full flushed only costed me like 40bux.
I dropped my pan too, man the magnet looked like a black mush.
I did it when my car hit 36k
I did it just for a peice of mind, the car shifted fine and everything.
 
#12 ·
[quote author=John_in_the_LBC link=topic=128903.msg2761733#msg2761733 date=1227316765]
i do think it depends on the condition of the fluid. if it's still pink and feels/looks good, then a drain and fill is probably fine. if it's worn and black, a drain and fill will still leave 40%? of that crap in the system (although it will be diluted with the new fluid). crap is crap.
[/quote]

i suppose. although the fact is that you cant really tell the condition of your fluid by a small sample on the dipstick. you're still right nonetheless, if the fluid "looks" ok, then a drain and refill may be just fine.
 
#13 ·
do you change the tranny filter everytime you do the flush?? what did you guys do, because i got a filter and it looks the same as the one they sent but the one that came out of the car the nosle that sucks the oil up was longer then the one they sent for my car. We sent it back but they all come looking different then the one that came out of the car. But the part # was the same on both.
 
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