VW Transmission Slipping

[REM]

I have a 2003 Passat GLS with the 1.8T engine and an A/T. Lately the A/T is acting up. When I slow to a stop, the engine stumbles and then catches itself. It's very similar to what happens when you have a manual trans and wait too long to let out the clutch when you're slowing to a stop. Also, I've observed some slipping in various situations such as downshifting or sudden acceleration. When it downshifts, it sometimes bangs into the lower gear. The car has only 74,000 miles and has had pretty gentle use.


Would it make sense to first try flushing and replacing the fluid and strainer. VW, I believe, says the fluid doesn't need to be changed. It's there for life, they say. I'm not sure I buy that.

What should it cost for a flush, filter replacement, and pan cleaning? I called the local VW dealer and asked them about this and they acted like there was something wrong with me for asking this.


Any other ideas? Thank you.

[Eric]

I have a 2003 Passat GLS with the 1.8T engine and an A/T. Lately the A/T is acting up. When I slow to a stop, the engine stumbles and then catches itself. It's very similar to what happens when you have a manual trans and wait too long to let out the clutch when you're slowing to a stop. Also, I've observed some slipping in various situations such as downshifting or sudden acceleration. When it downshifts, it sometimes bangs into the lower gear. The car has only 74,000 miles and has had pretty gentle use.


Would it make sense to first try flushing and replacing the fluid and strainer. VW, I believe, says the fluid doesn't need to be changed. It's there for life, they say. I'm not sure I buy that.

What should it cost for a flush, filter replacement, and pan cleaning? I called the local VW dealer and asked them about this and they acted like there was something wrong with me for asking this.


Any other ideas? Thank you.

Hi REM,

In most cars equipped with automatic transmissions, it's routine service to periodically drain the fluid and replace the filter - because filters do get clogged over time with the small particles that wear off internal friction clutches and so on - and because the fluid gets contaminated and/or its additive package loses potency, etc.

I'm surprised to learn that VW consider it unnecessary to ever change either the fluid or the filter - and that the dealer's treating you like you're crazy for asking about it. Maybe VW has developed a transmission that does not wear internally and thus its internal filters never get clogged? (In which case, why even have a filter at all?) And I have never heard of any oil or hydraulic fluid that never deteriorates.

Have you?

Given 70,000-plus miles without a change of either the fluid or the filter, I would not be surprised to find trouble such as you describe. Automatic transmissions (as you probably know) transmit engine power hydraulically, through a torque converter and valve body. The valve body has many small passages in it. Even a very small bit of debris lodged in one of these passages can affect the transmission's functions significantly. Varnishes can make internal valves/accumulators, etc. sticky - which results in weird shift quality and so on.

I hope it is not permanent damage and would recommend as a first step, that the old fluid and filter be changed.

Bottom line, changing out the fluid/filter is not going to hurt anything, is almost certainly necessary (given the mileage) and may just fix your problem. Be sure to use the exact type of fluid recommended by VW, though - and filter, too. Some brands of cars are very sensitive to the type of fluid used and use of the wrong type brand can lead to premature and very expensive failures. etc.

I would look at this as routine maintenance, no matter what VW or the dealer tells you.

Now, if the problem persists, there may be a bad sensor (modern automatics are electronically governed) or some other external issue. A good repair shop (not necessarily your VW dealer) ought to be able to track that down if necessary. But changing the transmission's fluid/filter is essential (in my opinion) at this mileage, regardless of other possible problems.


Hope this helps - and welcome to the site!