98 PGV rumble when shifting into overdrive.

I took the van to a mechanic and had the transmission filter and fluid changed at the first sign of trouble. The Mechanic said there was excessive metal shavings attached to the magnet. The van still rumbles when shifting. I have read through a lot of post regarding this issue and I have some questions.

This is my third transmission. I put the second one in about 5 years ago. Could my problems be related to a bad or out of date TCM?

If the TCM is bad and changing it stops the rumble, is this transmission on it's way out no matter what I do?

The Mechanic put ATF +4 fluid in but only about 6 quarts. Doesn't the transmission hold about twice that?

What would happen if there was already ATF +3 fluid in the transmission and ATF +4 is added?

If the transmission is on the way out ; how many more miles could I get? Basically should I park it?

6 qts. is right for a drop the pan change the filter. The total capacity is about double..but 6 qts is all you'll get out on a filter change. ATF-4 replaces ATF-3 4 is just supposed to have more of the additives than 3. I think you are fine on that regard. How often do you change the filter and fluid. I suggest 30k miles to avoid trouble.

Is there any chance that you are over heating? over heating the trans fluid is quickest way to cause problems with the trans on these vans. I assume that you don't have an add-on trans cooler..so it's the trans cooler in your radiator that cools the fluid. If you are experiencing any overheating on your engine temp gauge you're also having a problem with cooling your tran fluid.

my 97 has 181,000 miles on it and is going strong...but I have changed the fluid @ 30k intervals since 100k or so.

Spit

No i haven't done any regular maintenance other then checking the fluid off the stick. If it looked darker than usual I had the filter and fluid changed.

There are no signs of overheating that I can see. Temp gauge rises to the same spot it has for years. It happens when I leave work. It's only running for about 2 min before I'm up to point the van shifts to OD. I have noticed it a little on the lower gears and when it down shifts to first.

I don't think the van is worth another transmission. Its close to 190K and rust is starting to get the best of it. I was just hoping to nurse it til next summer. It's sounding like I'm not gonna make it to October!

OK I'm thinking I might try another TCM. Where is it located on the van?
What do I need to know when replacing it? Will just having the numbers off it be enough?

Just curious. When they changed the previous trannys did they also change the torque converters and flush the cooler especially if they saw metal shavings then? Not doing both is a sure fire recipe for short tranny life. Metal shavings get traped in the cooler and TC. Install the new tranny and those shavings are still there circulating in the system.

Before you "park it" give it a month or two and see if there are more shavings. If there is then at that point any further investment is questionable. It could last months or weeks. Much more than a year is questionable. In the mean time before changing the TCM you might want to verify the latest software update is installed and if there are any stored transmission specific codes. The TCM is on the passenger side fender wall under the hood just forward of the power steering reservoir. Just need the entire part number to get a new one.

Do I have to go to a dealer to have the TCM flashed and codes read?

I couldn't tell you what was done as I lost all my vans papers during a recent move. The transmission shop had a great reputation. I emphasize the word had. My experience was terrible. I had it back several times for leaks after the rebuild. Then it was finally fixed right or so I thought. Then just over two years later I had problems shifting and took it back and they said filter was plugged. They replaced it and all seemed well until the next day when I pulled out of work only to loose second gear...for good. Looking back I suspect they put the wrong fluid back in it. They told me the filter being plugged caused too much damage and I needed another rebuild. Rather than have it towed 50 miles back to town an to another garage I let them rebuild it again. No leaks this time and I thought it had been done right this time. Each rebuild cost me $1500 bucks. And like a fool I said to the wife"Well, at least we won't need to do this again". A few months ago I noticed my speedometer was off by 1 to 2 MPH over the exact speed. Hadn't been a problem so I left it. I have not gone back to that shop since and do not recommended them to anyone but when I drive by there's always a full lot of customers.

The transmission is still going but it has started to do something a little different.
Sometimes it doesn't try to shift into overdrive at all. If I let of the gas once I get up to speed it will eventually go back to shifting but rumble when doing so. This mostly happens when I leave for work in the AM or leave for home in the PM. Once it does shift it seems to go back to the rumble when shifting as before. Once in a while the van shifts normally. The questions I have are:
Is this a new problem or just the transmission getting worse?
Could this be a new symptom pointing to the TCM as the culprit for all my problems?