Hello, I'm a novice garage mechanic who loves to learn new things, and I've been progressively doing more and more of my own vehicle maintenance and repair over the last few years. My knowledge is growing, but I have a LOT to learn.

I've only recently directed my attention to understanding drive-train systems as my daughter had Transmission issues and had someone replace hers with a used one... then of course hit a deer and smash the van to where it now rests at a junk yard.

I changed my wife's rear differential fluid on her 2011 Honda CRV last weekend, and it made me realize that in all the time I've owned my 2008 Dodge Grand Caravan 3.3L Flex fuel, which now has 220K miles on it, I've never changed the transmission fluid.

As that hit me, and I began prepping myself for changing the transmission fluid, I can't help but fear that after so long (at least 130K of those miles were mine) is it more of a risk to change it now? Will changing it now make the transmission fail sooner?

The reason I wonder is that many years ago as a youth of 19 I owned a 1989 Regency Olds 98, and I got a job at a car dealership as a Service Porter and one of the mechanics offered to do a transmission fluid change for me. I wasn't having any issues, but he was trying to get me into the mode of performing maintenance (it took many years before it actually sunk in). We changed the transmission fluid, and less than a week later... I had no reverse, then failure of first gear. Logically or not, the thought stuck in my head that maybe the sludge was what was keeping the gears from slipping the whole time. Flash forward 25 years, I start to experience shuttering in reverse in my van that I never experienced before.

It would always clunk when shifting from park to Reverse when parked at an incline, but never shuttering... until now.

I checked my Transmission fluid levels, and I was a little low but not awful. Granted the fluid looked black and not the red color it's supposed to look like, it wasn't too low. I topped it off, and now I plan on changing the Transmission fluid and filter on one of the upcoming weekends.

Is there any advice you can give me, things to look for while I'm changing the transmission fluid, tips to make it easier, what to do while I have it open already, etc?Am I supposed to change the fluid after a certain mileage? I assume if I have a dipstick it isn't a "sealed" system that is supposed to be maintenance free... but I just don't know. Any specific Transmission fluid that would be better for a car with this many miles on it?

I would greatly appreciate any input you have, as I have a great respect and fear of transmissions.

 

Will changing it now make the transmission fail sooner?
Whatever damage you've done by neglecting maintenance is already done. However, changing fluid on a neglected transmission can expose those problems as it dissolves oxidization deposits in the valves, servos and clutch packs. In this case, if it ain't broke, don't fix it.

 

I changed my transmission fluid and filter at 80k miles and noticed an improvement.

 

have heard the stories about the dangers of changing old trans fluid but its never happened to me. The theory is detergents in the trans fluid will loosen sludge and send it through the valve body or a fluid passage.

I've bought 4 high milers ranging from 175 to 250 000kilometers...changed the filter and performed a complete fluid exchange on each vehicle and have not had a problem. the trans service interval for most vehicles is 90 000km. I do not believe in filled for life fluid. Life for the engineers means; when the powertrain warranty expires.

 

Would you ignore an engine oil change if you knew it was long over due? So it doesn't make much sense to ignore transmission service either, does it?

There is some risk in changing the fluid after so long, but the fact that the fluid is black in color (and probably smells burnt) is a sign that the transmission fluid isn't doing it's job anyway. I agree that any damage that's been caused by this has been done, but that doesn't mean you should ignore it and drive on the hopes and dreams that nothing will ever go wrong either.

The advantage to changing it now is that you can look for signs of serious internal damage and keep yourself from getting stranded by pro-actively repairing/rebuilding/replacing the transmission while you still have time to plan for it.

Here's how I would do it, especially if I'm doing it myself instead of having a flush service performed:

1) Buy twice the ATF you're going to need, and I don't mean for a filter service - I mean twice the total system capacity. Most filter services require 6-7 quarts to refill, but most systems hold between 1.5 to 2 times as much fluid as is required for a filter service. You don't need anything fancy - whatever is currently recommended for your van that meets spec is fine. (I'm not a Dodge expert so I don't know exactly what you need - check your owners manual for type and capacity - a parts store can check if there's an updated spec on the fluid.)

2) Buy a filter kit and flush/cleaner chemical. We use the "high dollar" stuff at work, but any off the shelf trans cleaner will do.

3) Do an initial drain and fill of the pan - even if there's a drain plug, drop the pan. SLOWLY pour the fluid out of the pan (5 gallon buckets are very handy at this point) and look for large pieces of metal that are in the bottom of the pan - anything about the size of a splinter or bigger is cause for concern, and you should start planning for a trip to the transmission shop or junk yard. You can expect to see metal shavings with a consistency of sawdust as well as a black gritty material.

4) Thoroughly clean the bottom of the pan and magnet. Inspect the existing filter - if it's still in place, DO NOT remove it. If you can see any of the filter media without removing it, see if it's still in tact or falling apart. If it's still in tact, leave the filter in place for now. However, if it's falling apart, or if it has fallen into the pan, go ahead and replace it with the new one.

5) Reinstall pan and fill with new fluid. Without driving the van, run engine at idle (it's best if it's up to operating temperature), cycling through every manual gear you have 2-3 times and pausing in each gear for about 3 seconds (my preferred method is to go straight to the lowest gear and then work my way back to park).

6) Drain pan again (this is where it's great to have a drain plug, but most transmissions don't so you'll need to be patient while doing the fluid change this way).

7) Refill with new fluid and add flush chemical. Go on a drive, making sure to cycle through each manual gear as you take off from stops. Hit the highway and cruise for about 10 minutes, then return to the garage and cycle through the gears one more time.

8) Drain pan again and fill with new fluid. If you didn't previously install the new filter, now is the time to do it.

9) Repeat this process until you have exhausted all of the ATF you bought. Doing it this way, you are slowly introducing fresh fluid (and the detergents contained in it) to the system and are less likely to cause a "shock" to the transmission with a total flush and fluid service all at once. This will slow down the cleaning process and should prevent any large deposits from coming loose all at once, but it also helps clean the transmission more thoroughly as you cycle through the gears.

Again I want to stress that any splinter size or bigger metal particles in the pan is indicative of internal problems that will have to be addressed, so if you do find them, I wouldn't proceed beyond step 4 - just put the new filter in it, install the pan and start making plans for the repair or replacement because sooner or later it will have to be done.