changing trans fluid a bad idea?

[USSEnterprise]

Hi,

I work at PepBoys, and they tell customers that changing trans fluid after having not changed it for a long time can do damage to the transmission. Is there any truth in this? My T4R has 100k miles and the fluid is very dirty.

Thanks
Joe

 

[THatfield]

change it. I just changed mine for the first time (that I know of) in 90k miles. Last recorded change was 10 years ago at 52k, I just did a drain and refill at 145k.

 

[gamefreakgc]

Yes and no.

Changing the fluid is necessary for the life and longevity of the transmission. Once the fluid is discolored it needs to be replaced. It's how you replace it is what can be bad.

A lot of shops have switched from using power flush machines because they will kick up metal fragments off the magnet and distribute them throughout the transmission. As you could guess, this will end the usable life of your transmission pretty quick.

A drain and fill though poses no risk to the transmission and is improves fluid quality. That's what I would suggest doing.

 

[T4R2014]

Some will say yes and others will say no. IMO, you are only at 100k. Change it.

 

[USSEnterprise]

Is it safe to flush it completely via the cooler line method?

 

[mar5168]

Change it. Talk to any Toyota tech and they will tell you that even though its not listed in the owners manual and its technically a "sealed transmission" the fluid should be changed at 100k. NOT FLUSHED. A drain and fill and then check the fluid level when the trans is at operational temp.

P.S. I was a honda master tech for 7 years, never flush, always follow factory service procedures, and never believe a "sealed transmission" doesn't need some form of service.

Also, its not the distribution of metal that causes the transmission failure after not being serviced and then having a service. It's the removal of the fluid which acts as its own friction modifier. Think of it this way; your trans is essentially a bunch of gears linked with a couple wet clutches. The clutch material in the trans fluid as a colloidal mix gets removed and thus reduces the static friction of the clutches.

 

[Kanger328]

Is it safe to flush it completely via the cooler line method?

I did this 30K miles ago. Running well with no problems. Just be advised that when you start the engine, fluid comes out FAST from the cooler line. I used 3-5 second intervals.

 

[ukrunner]

At 180K miles I had the milkshake issue. I removed the transmission the next day, took out everything I could reach from the front and bathed it in clean fluid and put it all back together and refilled it. I cycled about 60 quarts of fluid through it and saved the transmission. I bought drums of fluid from Napa. Its done about 25K miles since and the fluid still looks as clean as the day I did it. I realize I was extremely lucky but the point is, after all that crap in there and all new fluid, for you, changing dark fluid shouldn't be any problem at all if you drain and refill then drain and refill again soon after.

 

[frank_socal]

my buddy owns a transmission shop and he says the same thing. That if you change the transmission fluid after having not changed it for a long time, over the recommended interval, that it can do damage to the transmission. Something about transmission fluids having detergents and doing more damage to the clutch discs.

 

[ben550]

Is it safe to flush it completely via the cooler line method?

I have used that method two times on two different vehicles without any problems. The one was on a 2004 4runner with 135k miles. I plan on doing my 06 shortly... It has 160k...

Using the cooler lines is a good bet. I would not use the power machines.

 

[gamefreakgc]

my buddy owns a transmission shop and he says the same thing. That if you change the transmission fluid after having not changed it for a long time, over the recommended interval, that it can do damage to the transmission. Something about transmission fluids having detergents and doing more damage to the clutch discs.

Yeah, this is why the drain and fill is a good method. It only replaces about 4 quarts of fluid and doesn't shock the system with new detergents and such.