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Transmission fluid flush and front end rattling issues

Hello everyone!

I have a 2002 Kia Rio Cinco, (named Simple Jack) with about 150k miles on it, that I have been bringing back from the dead. I’ve replaced the shocks and struts, brakes, wheel hubs, wheel bearings, part of the brake line, the timing belt, motor mounts, fan, valve cover gasket (needs to be redone because my mechanic got sloppy), spark plugs & wires, windshield and wipers, and the radio. I sound proofed the interior, pulled the seats and carpet out and power washed them. I am also doing some body work on it. Normally, I am pretty good at troubleshooting the problems, but not-so-much doing the actual repairs. I tend to panic, and get paralyzed by the fear that I will break my car worse than it is. So I generally figure out what is wrong, order the parts, and pay someone to do the fix.

I have a couple of questions, that will probably be easy for someone with more experience than I have.

The first was about doing a transmission fluid flush. I got the filter and the transmission fluid and while my ex-mechanic was breaking my car the last time, I asked if he could do the flush. He said he would not do it because the transmission was too old and it would break the transmission if he did it. Since the fluid looked dirty and probably had not been changed for a while, his logic was that the parts had a layer of dirt on them that would be flushed away with the fluid change. This would interfere in the operation of the transmission because the parts would no longer be able to make contact with each other.

At the time, this made sense to me. However, after some less than stellar repair attempts, I have some doubts as to the validity of his claim. So I am asking you all if this makes sense.

The second question is a problem with rattling. I had purchased the tie rod ends, front stabilizer and bushings for the suspension. I asked my mechanic to change all the parts when he did the front shocks and again I asked when he did the front wheel hubs. He said that I didn’t need the crap. So my car has a weird rattling when I drive. It sounds like it comes from the top of the engine, but at speeds around 60mph, I have some vibration in the steering, too. I am concerned that something may be wrong with the steering or maybe it’s just the alignment. However, I think the rattling may be independent from the vibration. I have not been able to determine the cause of this and my plan was to just keep replacing parts until it is fixed. I figured I will have a new car by the time I am done. Do you have any idea of what I can check next? Should I do the tie rod ends? The bushings? The CV joints? I know I need a new mechanic.

First…a lot of mechanics believe in the fairy tale about leaving a transmission alone because it has old fluid in it. New fluid is better than old fluid regardless of what the old wives tales say. I never recommend flushing an automatic transmission…never. Drop the pan, replace the filter and refill with the proper transmission fluid.

Second…take your vehicle in to a front end specialist or a good independent mechanic and see what they have to say after the front end is inspected.

Third…you are absolutely right…you do need a new mechanic.


I second everything that missileman stated.

Or you could just jack up the front end and shake the tires back and forth and see if they pull back and forth at all but it is probably most likely a bushing or wheel bearing

If you look at the right hand side of the post it will show the date posted . In this case Jul '13 means the last time this thread was posted to was July 2013 . 6 years ago so the person may not even have the vehicle anymore.


Here’s a question about ‘flushing’ the AT - is it an actual flush, or is it a fluid exchange (oil fluid replaced by new fluid)? If it’s an exchange, that further makes the ‘don’t flush an old AT’ more of a myth.

(edit) Yeah, just noticed @VOLVO_V70’s post about the date. Leaving this here anyway in case someone else is in a similar situation.

Good lord, from the sound of it you wouldn’t have broken it worse than it already was. :wink: You had a LOT of work done on that thing.

Glad he’s your ex-mechanic.

Here’s where that myth comes from. Someone goes an insane number of miles without ever replacing the transmission fluid, and this causes premature problems with the internals. Then they finally get it “flushed” and some time later, those prematurely-damaged internals finally die. Since the last thing that was done to the transmission was the flush, that gets blamed rather than owner neglect.

Presuming that the “flush” is done properly (i.e., using the right fluid), it’s not going to do any harm to the transmission. It will not fix harm that has already been done, but it won’t cause more.

You definitely need a new mechanic. I would also suggest that you think long and hard about whether or not you also need a new car. This is an old Kia, not a rare 1960’s Jaguar. Is it really worth putting this much time and money into? Unless your ex mechanic is very, very inexpensive it wouldn’t surprise me if you could have replaced the car with something less neglected with what you’ve spent.

It’s a fluid exchange.

You disconnect a cooler line from the transmission to the radiator. The machine is connected between the cooler line and the radiator. Now the machine is part of the loop.

You start the engine, and the pump within the transmission pumps the old fluid out while the machine pumps new fluid in. This is continued until the transmission fluid being pumped out of the transmission is the same color as the new transmission fluid being pumped in.

This replaces 100% of the transmission fluid.


Thanks, that’s what I thought. Folks hear ‘flush’, and they think ATF is being pumped around at high velocity, stirring everything up. Instead, it sounds like ‘business as usual’, just with new fluid replacing the old.