Dumb Transmission question

[markl9999]

Pardon my ignorance, I really am backwards when it comes to cars but.... I was told by an oil change guy that if you had never had the transmission fluid changed and you're up to 100,000 miles then you shouldn't ever change it as it gets used to all the gunk. We have a matrix with about 98,000 and i don't know if the transmission fluid has ever been changed. I want to do it as we'll be towing a trailer in a week but don't know if the advice I got was good or not. Anyone have any ideas? The car has been fantastic up to now so don't want to upset the delicate balance.

[humanoid]

I would just do a drain and a refill at least 1x and not a powerflush. The flush may loosen things it wasn't supposed to loosen.

[Pete_05_Mat]

I have heard the same thing... My Matrix has 130K on it and I have never changed the tran fluid or tran filter.

I don't know if this is the best thing to do, but, at this point I don't think I am going to change it. If I had been on the ball and changed it every xx,000 miles as recommended, I probably would continue to change it.\\

[edbso]

I did a drain and refill over 100,000 miles and my XRS.
used synthetic Redline. Also on my automatic M3 at at over 100,000

Just do it

[Pete_05_Mat]

Hey Edbso

Do you think, with 125,000 miles, I can still just drain and refill the transmission fluid with out incident?

I have been wavering back and forth as to whether to do it or not

...thoughts????

[edbso]

Here is the OLD THEORY. As transmission fluid "gets tired" sludge and varnish builds up in the filter, on the case in the lines and essentially all over. The over blown fear is that "refreshing" of the fluids with their new additivie package will cause this sludge and varnish to break free, clogging the filter and turning the transmission to toast.

I think this is terribly over stated and without a moments hesitation would strongly recommend a drain and fill with fresh synthetic fluid.

The only transmission I would not drain and refill would be one with metal filings obviously visible in the fluid. At that stage the transmission is already toast and will be failing very soon.

I used to always add a transmission cooler when I did the drain and refills but with better synthetic fluids I no longer do that.

In summary, just do it!

[humanoid]

Drain and refill would be OK IMO. But don't do a powerflush, I think that would be a bad idea.

[Pete_05_Mat]

Hey Humanoid,

I appreciate the advice, it's just hard to read your post with that Laker's banner in the margin

[humanoid]

^ don't be jealous

[circuitsmith]

I posted this in another thread, but it applies here too:

The manufacturers have gone too far making their cars seem like they don't need much maintenance. Honda got burned telling customers to have the valve lash checked at 105k miles on an engine that really needed it at 30k.

Everyone I've met who sees the insides of an automatic transmission on a regular basis says the fluid should be replaced at least every 30k miles, regardless of what the manual says. The manual is set up to get the vehicle through the warranty period, not maximize life.

And the fluid should be changed the right way. No shortcut flushes that can stir up debris. No "universal" swill. Drop the pan and clean it. Change or clean (if applicable) the filter. Refill with the manufacturer's recommended fluid. Do a fluid exchange if the old fluid was in bad shape (not normally needed if done at 30k)

[shortlid]

Ya, just drain, drop the pan replace the filter/screen and refill with factory spec fluid. Don't tow a trailer during the summer without changing it. THAT would be asking for trouble, just like a power flush "bad idea at this point"