Transmission Fluid Change: Yes or No

[FrankAbagnale]

Long time listener, first time caller.......

I am here to profess my sins, but also to seek out the best solution. I own a 2003 VW Jetta 1.8T GLS with ~145,000 miles. I have never drained/flushed my transmission fluid. Bought the car around 40,000 miles, so it is possible it was done at that time, but let's assume it hasn’t changed since it rolled off the floor. The only positive, through no work of my own, is I haven't had any issues with the transmission as it is right now.

I recently began seeking out a transmission fluid change, but I am reading conflicting reports on whether it will be best to leave it as it is or get it flushed. I have called a handful of places, and each has cautioned me about changing the fluid, and they recommended leaving the fluid in my car (The emerging theme is the fluid replacement will disburse potential loose bodies within the transmission, therefore causing damage). On the other hand, one business told me I needed to seek out a place that will flush the fluid, as this will solve the problem listed above. I have also seen posts on this site and others questioning the validity of transmission fluid changes actually leading to future damage (The emerging theme here is that people seek out a fluid flush only after slippage has started).

What decision should I make - Should I change the fluid? Or leave it alone?

 

[Jimzz]

I would do a simple drain/fill with the correct fluid. This will also check the fluid level which is very important.

 

[Yuriman]

I can't imagine draining the transmission would loose more junk than driving.

I drain and fill mine every once in a while.

 

[skyking]

Take your question over to to vwvortex or tdiclub to get a good answer, IMO. I have mk4s but all are 5 speeds so I don't have any experience with the 01m transmission.

 

[JulesMaximus]

A VW with 145,000 miles on it?

My advice to you would be to get rid of it.

With the money you've made counterfeiting and now working for the FBI surely you could afford a better car.

 

[FrankAbagnale]

A VW with 145,000 miles on it?

My advice to you would be to get rid of it.

With the money you've made counterfeiting and now working for the FBI surely you could afford a better car.

Well played, sir

 

[996GT2]

The old way of thinking was that if your transmission fluid hadn't been changed in 100k miles or more, then there might be junk in there that could be dislodged by doing a fluid change, which in the end does more harm than good.

However, I have not really seen much evidence to back up the truth of this statement, so I would lean towards it being safe to change the fluid at your mileage.

Here's what I would recommend if you do decide to change it:

Do not do a transmission "flush". Most manufacturers recommend against flushing the transmission, and only recommend drain and refill of the fluid. If you want to get most of the old fluid out, simply do 3 drain and refills with a little driving in between each one.

 

[skyking]

^ that is the flush that I do on the hondas.

 

[Mide]

I always do a drain/fill. No problems yet.

 

[996GT2]

^ that is the flush that I do on the hondas.

IMO, this is the only acceptable way to change the transmission fluid on most modern cars.

If OP is concerned about new fluid possibly loosening up some old gunk and causing damage, what do you think doing a pressurized flush of your transmission is going to do?

 

[skyking]

no kidding.
Our pilot only gives up 4 quarts on a drain/fill, so if it is acting up I do a couple back-to-back after a few miles of driving.

 

[pauldun170]

Assuming this is an automatic

On some cars, the transmission is considered a "sealed unit" that does not require service, hence nothing in the service schedule for the car. the transmission is designed to last the "lifetime" of the car.
Depending on the car, a sealed unit can actually last the lifetime of the car where no service is required. Unfortunately, lifetime can be considered "length of expected ownership of vehicle\years vehicle would qualify as something able to be sold by a dealership used car lot.

For VAG products, I wouldn't go past 80K on a "sealed unit" and then perhaps go to 40K intervals from there. I think on certain configurations (Audi), 40K intervals from the start.

On our Mazda, we go with every 20K. On our previous Isuzu, never bothered and that was totaled at 140K with perfectly operating transmission.

As for your Jetta, feel free to change the fluid. Then sell the car while you still can.

 

[BlitzPuppet]

Be careful when changing transmission fluid on cars that are way past due for the service, you can easily run into problems.

 

[Vdubchaos]

I have never done any transmission fluid change on any of my cars. Which include VW Passat 1.8T (2 of them) with over 250k miles.

I never had any transmission problems.

Sealed units do come with Synchetic fluid...

VW folks do recommend doing so every 105k miles or so.....

 

[Excelsior]

On my 2001 VW, I didn't change the automatic transmission fluid and filter until about 130K. I'm glad I did it, but it was purely preventative. There was zero evidence it needed to be changed prior to dropping the pan and zero evidence once I examined the pan and the discarded fluid.

It was good for piece of mind though, and not terribly expensive. Vdub is right though, they come with synthetic fluid and IMO are very solid transmissions (at least the one on my Passat).

 

[BUTCH1]

The old way of thinking was that if your transmission fluid hadn't been changed in 100k miles or more, then there might be junk in there that could be dislodged by doing a fluid change, which in the end does more harm than good.

However, I have not really seen much evidence to back up the truth of this statement, so I would lean towards it being safe to change the fluid at your mileage.

Here's what I would recommend if you do decide to change it:

Do not do a transmission "flush". Most manufacturers recommend against flushing the transmission, and only recommend drain and refill of the fluid. If you want to get most of the old fluid out, simply do 3 drain and refills with a little driving in between each one.

This, if one wanted to go the "flush" route it would have to be begun at a young age, like 30K, IMO once your past 50K don't even think about flushing, just a drain, replace filter, refill. Be sure to use the EXACT fluid you car manufacturer calls for, "universal" transmission fluid is a very bad idea in any car. If it has a dip-stick for checking fluid I used to do a "cheater-change" every 20K, I would snake a clean piece of aquarium tubing down the hole and siphon out 4 qts of fluid and re-fill, most cars have unfortunately done away with the dip-stick and it pisses me off.

 

[WT]

I had a full flush done on my Kia SUV at 40k miles, and replaced the ATF with a synthetic. It cleaned up a lot of the sloppy upshifting I was getting, especially when towing my trailer. The shop recommended again a drain/fill since nearly 15-20% of the old ATF would 'hang around' in the tranny and not be properly removed. Total cost was $271.

 

[996GT2]

This, if one wanted to go the "flush" route it would have to be begun at a young age, like 30K, IMO once your past 50K don't even think about flushing, just a drain, replace filter, refill. Be sure to use the EXACT fluid you car manufacturer calls for, "universal" transmission fluid is a very bad idea in any car. If it has a dip-stick for checking fluid I used to do a "cheater-change" every 20K, I would snake a clean piece of aquarium tubing down the hole and siphon out 4 qts of fluid and re-fill, most cars have unfortunately done away with the dip-stick and it pisses me off.

There are cars without a ATF dipstick? How do you check the fluid level?

The shop recommended against a drain/fill since nearly 15-20% of the old ATF would 'hang around' in the tranny and not be properly removed. Total cost was $271.

This is true, but only if you choose to do a single drain and refill.

If you only do a single drain and refill, there will be about 50% of the old fluid left in the torque converter. That fluid only gets cycled around if the transmission is actually moving. Thus, if you do the drain and refill process 3 times and do some driving in between, you can get >90% of the old fluid out.

 

[BUTCH1]

There are cars without a ATF dipstick? How do you check the fluid level?



This is true, but only if you choose to do a single drain and refill.

If you only do a single drain and refill, there will be about 50% of the old fluid left in the torque converter. That fluid only gets cycled around if the transmission is actually moving. Thus, if you do the drain and refill process 3 times and do some driving in between, you can get >90% of the old fluid out.

Yes, MANY without, GM started dropping them in '98 Ford a year later, my owners manual states " if you notice fluid leaking on your driveway, take it to a dealer"..nice, huh?. There is a bolt one has to remove on mine and with the temp just barely warm the fluid should be at the bottom of the bolt-hole. In order to check mine at home I would have to put the car on 4 jack-stands (and make sure it's level), from what I've heard Ford's is even worse PITA to check. I guess they were afraid people would add the wrong type of fluid so now we have a $4,000 part that will self-destruct if it gets to low on fluid and no means of checking it, God that pissed me off, I actually went online looking for an after-market add-on but found none.

 

[Blain]

Flush, refill and move on with your life.
A "flush & refill" is just too easy to bother with 3 drain & refills.

 

[Vdubchaos]

On my 2001 VW, I didn't change the automatic transmission fluid and filter until about 130K. I'm glad I did it, but it was purely preventative. There was zero evidence it needed to be changed prior to dropping the pan and zero evidence once I examined the pan and the discarded fluid.

It was good for piece of mind though, and not terribly expensive. Vdub is right though, they come with synthetic fluid and IMO are very solid transmissions (at least the one on my Passat).

Passat transmission and Jetta/MK4 transmissions are completely different beasts.

B5 Passat Transmission is probably one of the best 5 speed units that VW/Audi has ever build (IMO).

My car has almost double the horsepower and I have never replaced a clutch or had any transmission problems (again, 250k miles/15 years of ownership)

 

[Vdubchaos]

DO NOT FLUSH, EVER.

If you do so, you will kick up all of the metal shavings etc into the hears/mechanism of the transmission.

Quite opposite of what one is trying to accomplish with maintenance (creates new/more problems).

 

[mvbighead]

I've had flushes done in the past that didn't cause problems. I also had a flush done that really made a dramtic negative change to a truck that then required a 1400 dollar rebuild.

I kind of wonder, the dipstick tubing pump out 4 quarts method and replace method would seem to be the least impactful. You're simply swapping out old fluid with new. You're not disrupting anything. The new fluid would have more of the good qualities and should improve transmission performance with more lubrication and fresh additives.

Speaking of which, I should probably check my wife and my cars and see if a drain and fill should be done.

 

[Vdubchaos]

I've had flushes done in the past that didn't cause problems. I also had a flush done that really made a dramtic negative change to a truck that then required a 1400 dollar rebuild.

I kind of wonder, the dipstick tubing pump out 4 quarts method and replace method would seem to be the least impactful. You're simply swapping out old fluid with new. You're not disrupting anything. The new fluid would have more of the good qualities and should improve transmission performance with more lubrication and fresh additives.

Speaking of which, I should probably check my wife and my cars and see if a drain and fill should be done.

If you have an extractor to do it thru the dipstick, it's no different than draining it.

 

[Jimzz]

If you have an extractor to do it thru the dipstick, it's no different than draining it.

True but many do not have drain plugs. Of course some have drain plugs but no dipstick tube.

My last car was a Mercedes E350 and it had a drain plug, dipstick tube, but no dipstick. Had to buy a aftermarket one.

My current car a Cadillac CTS has a drain plug but no dipstick tube or dipstick. Have to put car on lift with it running to top/fill the fluid.