Dying Tranny?

1995 Plymouth Voyager 3.0 Litre V6 with no overdrive or tachometer and 154K Miles.

I am quite over distraught over this, since the second transmission has preformed flawlessly since 2004 and just over 50K miles until now.

Shop that has serviced my family's vehicles for over 20 years changed the coolant and the tranny fluid as well as the filter. They added an additive to make the tranny fluid 7170 since this is what the tranny needs. They know this is the second tranny.

When I picked it up last night and drove home I noticed reluctance in shifting up from hearing higher revs (It was 20F). I also noticed the higher revs today and while driving about 20-30MPH there was a loud BANG! Pulled over, nothing underneath the van, and no road debris or any fluids anywhere. A lady in a nearby house came running out because she heard the loud noise. I limped it in first gear (which sounded fine) about 200 feet to a friend's house. Towed it back to the shop using proper methods. Totaly milage driven: about 7

Shops says; "Piece of varnish must have dislodged and clogged one of the holes."

Why would there be varnish inside the tranny?
I look forward to everyone's input on what is wrong with the tranny and is the damage fatal?

Mechanics sometimes use the term 'varnish ' to describe the residue left over when a petroleum product evaporates, particularly gasoline.

In this case, 'varnish' was not the best word. "Debris" would be a better term.

I am a big believer in regular transmission fluid- and-filter changes. Doing so every 2 or 3 years is a great way to maintain a transmission in good working condition.

But, sometimes, if this maintenance is not done often enough, you can sometimes encounter trouble when it eventually is done. Transmission fluid has lots of detergents and additives in it that evaporate or wear-out over time. If you drive a lot with old fluid, normal wear-related debris can accumulate in the nooks and crannies inside the transmission.

When you eventually change the fluid and filter, the fresh, detergent-laden fluid hits the debris and dislodges it. The debris can make its way to the valve body (the device that actuates the gear shifts) and causes erratic gear shifts, including delayed shifting and excessive engine revs. .

As for the bang.....valve bodies have devices called "accumulators" which smooth-out the shifts. When an accumulator becomes stuck from debris, a very harsh shift can result.... sometimes so hard, it shocks the driveline and feels like something mechanical has broken.

Most likely, the shop will have to remove the pan and disassemble the valve body, clean it up and blow it out with compressed air, then reinstall. If they do this, ask them to make sure there is a magnet placed inside the pan. Mechanics and rebuilders love to throw these magnets away, (pure laziness imo), but they are an important part of protecting the transmission, because they hang on to metallic debris and prevent it from getting to the rest of the transmission.

When this is done, your transmission should be fine. Just change the fluid and filter more often than 50,000 miles :)

Good explanation.

I am curious as to why an additive was used, and not straight ATF+4?

The tranny fluid was changed at regular intervals and the shop monitored the fluid to make sure it was not getting too bad. I think they said too brown.

3 more questions: How many miles does one go before the tranny fluid is supposed to be flushed and changed? Thanks for the year intervals. Also, how many miles/years between engine coolant changes and flushes? What is ATF+4 by the way?

Thanks for everything and I am gonna jot down the notes about what you have typed for when I go to the shop tomorrow to figure out what is up with Ol' Sandy.

ATF+4 is a special transmission fluid designed for all Chrysler transmissions made in approx. the last 20 years. Although it looks like regular fluid, it is made differently.
It is ESSENTIAL that such Chrysler transmissions use this stuff. The use of any other fluid, (ie, Dexron II or III, Type F, etc) will cause the Chrysler transmission to eventually fail.

The fluid and filter change interval depends on the use the transmission gets, and the design of the trans itself. Hot weather driving, lots of city driving, driving with a lot of people or cargo in the car, trailer towing etc all place more stress on the trans and increase the required maintenance. So it's hard to pin down a change interval, but every 2 years is fairly frequent. If the van gets relatively gentle use, you could extend this to 3 or 4 years, or so.

You mentioned a transmission "flush". Is this what your mechanic has been doing? Mechanics love to sell the flush idea because it is fast and profitable for them, but does little to clean up the filter or remove the debris in the pan. Dropping the pan, cleaning it and actually changing the filter are much more valuable than just a "flush".

As for engine coolant..... if you have an all-aluminum engine or aluminum heads, changing the coolant every 2 years is a good idea.... but you can extend it to 3 if the vehicle sees relatively little use. Cast-iron engines are not so sensitive, and a coolant change every 3 years is okay.
This is for the regular, green anti-freeze. There are some long-life anti-freezes out there that are orange. For those, follow the manufacturers specifications.

The transmission pan typically holds about 25% of the volume of fluid in a transmission, so I would not consider the pan/filter a thorough service unless done in conjunction with (after) a flush.

Question for you MagicRat that mom just brought up. I quoted part of a previous post.

"As for the bang.....valve bodies have devices called "accumulators" which smooth-out the shifts. When an accumulator becomes stuck from debris, a very harsh shift can result.... sometimes so hard, it shocks the driveline and feels like something mechanical has broken."

How damaging is this shock to the tranny or other parts of the van?


The filter was changed and the fluid looked pretty good, but I do not know if the pan was dropped and cleaned out as well.
Several website say to use ATF+4 on four speed trannies, but my van is a 3 speed (3 forward gears) with no overdrive and I cannot find what fluid I am supposed to use.

I printed out the posts, highlighted the nitty-gritty, and am going to be having (hopefully) a civilized conversation in a few hours.

Thanks.

All is good with the van and the tranny is now behaving fine. Nobody is exactly sure what happened. Both times they cleaned out the tranny pan, changed the filter, and kept the magnet in place. Since there are not many hills around here and brakes are cheaper I stopped downshifting when descending. Thank you for all the help.

Chrysler Transmissions. DO NOT use anything but Chrysler ATF+3 or ATF+4 fluid. the fastest way to destroy a Chrysler Transmission, is ATF + the additives. In the last 10 years my Dad & I have owned about 15 to 20 Dodge & Plymouth mini vans. I have rebuilt more transmissions than I care to ever again.

Rule of thumb (and your manual will back me up) every 5th oil change replace the fluid & Filter on your transmission, and the transmission will last longer than the Van.

My last Caravan was a 1994 with the 3.3L 4spd, and I finally donated it to a JY with over 500,000 kilometers on the odo. I rebuilt the transmission once when I first got it at 150,000 kilometers.

Thank you for all the information. The mechanic said he used ATF+4. I get things mixed up, but I heard there is another name for ATF+4 and it is either 7170 or 7176. I have the actual number written down somewhere. Same tranny fluid I am told just different names.

Good news, you're back on the road. FYI:

http://www.centerforqa.com/

Thanks for the link. Good to know that ATF+4 is really what should be used.

- I had this problem with my 99 Plymouth Breeze same motor too! It turned out to be corrosion on one of the transmission connectors, the one on the front bottom.
- Initially to fix it I had the transmission rebuilt and that only solved it for a week. I would then disconnect the battery to reset the transmission control module, and it would drive fine for the day and then back to the same problem until I would reset the TCM. One day I found the corroded connector and cleaned the contact on the switch and the ran a small drill bit in and out of the connector by HAND. After I cleaned it I've never had the problem again.