Question about transmission fluid

When I bought my truck I had a guy from yourmechanic come and do a pre purchase inspection and he told me to change the transmission fluid (it was brown) then drive it for 10,000 miles and change it again. It's only been about 6 weeks since I changed it but I checked the fluid today and it's black. Also he told me not to change the fluid in the torque converter or drive train and said don't replace the filter either. Doesn't make sense to me but he's the mechanic right?my question is should I just go ahead and change the fluid again plus the filter and fluid in the torque converter or what would you recommend? I don't want to drive around with black transmission fluid because I think it's going to mess up the transmission.

 

Please confirm some details about your truck. Year and model, engine size, and type of trans. Is it an auto?

Your referrence to a torque converter suggests it is an auto trans. What doesn't fit is the color of the fluid. Should be red or dark red if it is getting burn't.

When you checked it, are you certain it wasn't the motor oil you checked?

Post up a picture of the dipstick you checked.

 

2002 Tacoma 2.4l Auto trans. I'm sure it was the transmission fluid dipstick.

 

As to your question about the automatic transmission fluid. There are at least 2 opinions on changing discolored fluid and there will always be a debate over it. If the fluid is severely discolored that means that it has seen its service life and should be changed, and in my opinion, gradually, like your tech said. Discolored does not necessarily mean burnt, burnt smells burnt. If it is burnt you are living on borrowed time. The friction material inside an automatic transmission is essentially paper glued to steel. The passages inside the valve body, the mechanism that directs the pressurized fluid to where it needs to go are not tolerant to bits of debris and the spool valves will stick or not operate and now you have funny/no shifts. Auto-transmission fluid has detergents in it and a sudden change with all new fluid will clean “too well” and dislodge more debris, this happens from time to time. This is why he recommended to gradually change the fluid. Changing the filter in the pan… I dont know why he recommended against that, again, like I said, multiple opinions.

 

You have a nine quart system....and you've only changed 2 qts....

So 2 qts new plus 7 old and black......


And its very wise to slowly flush that out over time.....if you don't know its history.

But at 2 qts at a time...its going to take several cycles.


Everybody's big on oil changes....not so much on coolant, atf, brake, steer, differential fluids.

Its really ashamed, these are just as important as the oil changes.
Especially as more of these sub systems parts are discontinued...
.....left with rusty junk yard...



I'd do same on the differential....change it and then do it again a year later....

Remember old contaminated fluid becomes cutting fluid.....especially at high temps....