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Changing Automatic Transmission Fluid

Voyager transmission fluid change and band adjustment

ATF+4 flushing kitI changed the fluid and filter, and adjusted the bands on our 1985 Voyager (2.6L, A470 3-speed, 118,000 miles). The fluid was no longer bright red, but tired dark reddish brown. No burned smell, no flakes, no particles, so that's good! I suspect (as the second owner) this is the first transmission fluid change it's ever had.

The purpose in posting this note is to encourage anyone with an A470/A413 (3 speed 2.6L or 2.2L) to change the fluid and filter if they think it's time. No need to pay someone else $35 to do a half-hearted job! It's a simple, uncrowded, easy to maintain design, and if you can do a valve cover gasket on an overhead-cam engine, you can do this (in my opinion).

Get that new ATF 3+ (Chrysler MS-7176, US$3.50 at my local CPJE emporium, get four or five quarts), get a real MoPar filter for US $7.95 and rubber gasket for US $1.70, and do it! [Editor’s note: in the years since this was posted, in the 1990s, Mopar moved to ATF+4, which is acceptable in the older transmissions.]

You'll need a decent torque wrench capable of reading down to 40 in-lbs for the band adjustment and up to 175 in-lb for the pan bolts, and a factory service manual or equivalent for the torque and backoff turns figures, but that's something most of us have anyway. Also, you'll need a Torx (TM) -type screwdriver (like the one used on the headlight housings) for the filter screws. The fastener sizes quoted are for the 1985 A470, other years may be different.

Watch out when you pull the pan, don't damage the sealing surface prying the pan off (do it gently and you'll be OK, it'll sort of jump loose all the sudden). Getting a premium gasket and sealing agent (if called for) is worthwhile.

One reader added: Automatic transmission gaskets should not be coated with RTV. It will cause the gasket to squeeze out from between the mating surfaces. The same applies to rocker box covers except at the point where the cylinder heads are split, and then that small area should be allowed to dry for a couple of hours before replacing the box covers which should have had the gaskets glued on with aviation type cement earlier, and dried in place by time to install. If the box cover gaskets are allowed to dry in place with the aviation type cement, a little RTV won't hurt, but it usually causes the gaskets to squeeze out from between the mating surfaces.

Always use a Fel Pro type gasket. They tend to expand as they absorb oil. There is an all rubber transmission gasket available that doesn't require any cement, but an extremely light coat of RTV or sewing thread to hold in in place.

Always, always re-torque the bolts a couple of times during the next month or so after installation.

Adjusting the low/reverse band is easy, you'll have to remove the parking sprag pushrod (e-clip) to gain access, then loosen the locknut with a 13mm open or box end or socket. The adjusting nut is a 6mm hex (I think that's what I used at least), torque it down carefully to the FSM spec then back it off the number of turns specified in the FSM. I painted two stripes 180 degrees apart on my 1/4" to 3/8" adapter to see when I'd gone 1/2 and one full turn.

Hold the adjusting hex when you tighten the locknut so it doesn't move. Don't forget to put the parking sprag pushrod and e-clip back in! Adjusting the kickdown band is also pretty easy, it's on top of the case under the throttle cable. It uses an 18mm locknut and an 8mm hex adjuster. Use an 18mm box end to loosen and tighten the locknut.

Clean the pan and case gasket surfaces thoroughly and gently so as not to gouge the aluminum of the case...a wire brush worked OK on the pan itself. Don't forget to put in the new filter and filter gasket! Clean the old residue out of the pan, and clean the magnetic residue off the ring magnet in the pan. Might as well do the differential cover gasket, too, since removing it drains the fluid out. I had a leak in the differential cover gasket anyway, so I had to do it. Watch out for the constant dripping from the case, try to keep the mating surfaces clean when you put the pan and cover back on, it'll help it seal better. If using RTV, use a 1/8" bead of RTV on the pan and cover, don't overdo it, ring the bolt holes, go slowly.

Watch out for the differential cover not being aligned with the case holes, just align the cover carefully and you'll be OK. Torque the pan and cover immediately upon putting it in, to keep the dripping fluid from messing up the seal (especially on the differential cover). Above all else, keep the insides of the transmission clean, no lint.

Put in the recommended quantity of fluid (4 qts US for the 1985 A470), and test it out! You'll be rewarded with a job as good as your capabilities allow, for much less money, and with high-quality parts and fluid. You'll also get a good look inside the tranny, to see what's up in there (any particles of old friction material in there, for example).

Flushing the system: a more complete method

I just used the Transmission Flush recommendation by James Bottger and it worked perfectly. My 1993 Chrysler New Yorker tranny cooler exit line was at the top of the radiator. After about 6 quarts of old fluid coming out ot the return, we got nice, clean red fluid. With this complete flush, new ATF+4, and new Mopar filter, the shifting reurned to normal. — J. Bridges, February 2010

While it's much better for the transmission to change the fluid using the method in [the above] article than it is not to change the fluid at all, this method only replaces about half of the fluid in the transmission. The best thing to do is to change out ALL of the fluid, and this is also something a person can do themselves.

First, drain the fluid from the pan, just like you would using Mr. Macfairlane's procedure. Once you've replaced the filter, the pan gasket, and reinstalled the pan, you're ready for the next step.

Fill the transmission to the proper level using the proper type of transmission fluid. Then disconnect the return transmission line (the line in which transmission fluid flows from the transmission cooler back to the transmission), located near the bottom of the radiator. There's two transmission lines connected in this location, and the bottom line is usually the return line. Once the line has been disconnected, attach a clear piece of tubing to the transmission cooler, the same diameter as the transmission line, approximately 5-6 feet long, using the transmission line clamp to secure it.

Russ Jennings pointed out that there is conflicting information about the location of the lines to the radiator. It is possible that the lines were rerouted over the years, or routed differently for different engines or carlines. When you route your lines, follow the original factory path.

Place the unattached end of the clear tube in a plastic, one gallon milk container and place it where it can be seen (like not under the car).

For the next portion of the procedure, make sure that the parking brake is set prior to continuing. Start the engine. The transmission needs to be put into "Drive" so the torque converter fluid is changed as well. Some transmissions will only circulate fluid through the torque converter only in drive. This especially applies to the electronically controlled transmissions. [Craig Sherman noted that Drive is needed for most transmissions, based on technical manuals]

After approximately 4 to 5 quarts (obviously, if it's more than 4 quarts, you'll have to turn of the engine, and fetch another milk jug) of fluid have been pumped out, you should notice a change in the color of the fluid. It should go from a brownish red color, to a bright pinkish red color. When this happens, all of the old fluid has been replaced with new fluid.

Be careful not to overfill the tranny during this procedure.

When completed, reconnect the transmission return line to the transmission cooler. Check the fluid level as you normally would, and add fluid as required.

This fluid change method is twice as good for your transmission as the method of only changing out half of the fluid is. Happy shifting!

Another system for changing automatic transmission fluid

James Dement provided the following:

Here is a simple way to change the transmission fluid in your Chrysler that doesn't even require you to crawl under the vehicle.

I learned that I can use about 6 or 8 ft. of clear vinyl tubing - probably only 1/8" or 3/16" ID. The type of low cost tubing you can get at your local home improvement or hardware store. What I've been using is actually the leftover home oxygen supply line from my late Aunt who had to use oxygen in her last year. She left us an abundant supply of this tubing.

I stick the clean tubing all the way down into the dip stick opening until it clearly is on bottom. Then I start a siphon by sucking on the tubing. You can easily see the reddish colored fluid moving up the tubing and towards you. When the fluid gets a few inches from the end you simply place the end into your container and the siphon action will do the rest.

I've done this on my Grand Caravan (A604) twice now and a relative's Dodge Shadow. If you are a reader of this site you already know which fluid you should be using - so pay the extra $1 per quart and use it.

Last year I got 4 qrts. out before the fluid stopped flowing. This year I got out 6+ quarts of fluid in total. I think I could have gotten more if I'd wanted to. Of course this method doesn't address the filter inside the pan. Next time I will do the traditional change and replace the filter as well. But for those of us who have been through the rebuilding process once (or twice) and have started to change our fluid more often, this is a convenient way to change the fluid without getting under the vehicle.

It will take all night and maybe a full 24 hrs. It is sort of like watching grass grow so don't waste time watching just check on it a couple of times during the day to make sure it is still flowing. When it stops you can easily tell from looking at the clear tubing. If the siphon stops after 3 or 4 quarts, I've found if you reposition the tubing and start again you may get another quart or two. Also, don't let the container you're going into with the old fluid get too high or the siphon could slow.

Try this if you've been putting off changing that transmission fluid. It takes only a few dollars of tubing, little time to start and only a few minutes of clean up. Do take that old fluid to a recycle center for proper disposal.

How many fluid changes?

People on the EEK mailing list discussed the issue of how many fluid changes are needed. Mathematically or in practice, two changes - three at most - seem to be enough. On the other hand, one complete flush may be best.

Ultradrive (41TE) transmission fluid flush

by Ted Mittelstaedt

Today I flushed my A604/41TE Ultradrive transmission in my 95 Chrysler Town & Country. I followed the general idea that James Bottger outlined. I started with a case (12 quarts) of Valvoline ATF +3 and a transmission filter kit. This kit contained the filter and a new pan gasket. The fluid replaced from the pan itself was 4 quarts, and I flushed the rest of the case through the dipstick while the transmission was pumping the old fluid out the transmission return line. Total cost of the fluid and kit was about $45. The flushing process from start to finish including road testing took 3 hours.

Russ Jennings pointed out that there is conflicting information about the location of the lines to the radiator. It is possible that the lines were rerouted over the years, or routed differently for different engines or carlines. When you route your lines, follow the original factory path. Alternatively, and preferably, check the factory service manual.

There were a couple things I noticed. First, there's an O ring that comes with the new pan filter - make sure this is on the filter when you install it. Also when installing the new filter, it takes quite a firm push to get the filter snapped in.

Next, I disconnected the return line at the transmission itself, not the radiator. This gave me existing rubber lines to use so I didn't have to muck with plastic tubing. It also turned out to be a very good idea because in the process I discovered that the cooling lines were REVERSED!! This is absolutely terrible because if this is done the tranny fluid gets little additional cooling and the tranny will fail quite quickly. This is particularly critical with this tranny cooler because unlike a more traditional downflow radiator where the tranny cooler is horizontal at the bottom, (and thus gets better cooling) the radiator on my van is a crossflow and the tranny cooler is vertical. It's worth noting that the tranny cooler in the radiator in this design is already really bad to start with because of this. Frankly, if Chrysler had simply dispensed with the tranny cooler in the radiator and put an airflow tranny cooler in the front of the radiator, I am sure that two thirds of the Ultradrive complaints would never have happened. INSTALL AN AUXILIARY TRANNY COOLER IF YOU OWN ONE OF THESE VANS!

A Controversy

Actually, the cooler was hooked-up correctly as the author originally found it. The hot fluid leaving the transmission must enter the cooler at the bottom where the cooler is coolest and exit to return to the transmission at the top where the cooler is warmest.

This seems backwards but there is a reason for it. The transmission fluid must be cool but not too cool. If the fluid is too cool, transmission shift performance will suffer. You will notice this on a cold winter morning when the transmission seems to take forever to upshift. Having the fluid leave the cooler at the top ensures that it will be warm enough to allow the transmission to function properly. Also, when adding an auxiliary transmission cooler, the auxiliary cooler is placed in series with the regular cooler but before the regular cooler so that the regular cooler may warm up the fluid sufficiently before sending it immediatly back to the transmission. - Carl H., Rochester, MI

Ted replies: I very strongly object to this for the following reasons:

1) The 1995 Chrysler factory service manual for the Town & Country, Caravan, and Voyager on page 7 - 19 has a picture of the radiator. The oil nipple for the transmission cooler at the TOP of the radiator is labeled "INLET" The oil nipple for the transmission cooler at the BOTTOM of the radiator is labeled "RETURN" This is in conflict with Carl's claim that the "hot fluid leaving the transmission must enter the cooler at the bottom"

2) Carl's claim that: "when adding an auxiliary transmission cooler, the auxiliary cooler is placed in series with the regular cooler but before the regular cooler" is in direct conflict with page 7 - 22 of the already cited Factory Service Manual. I quote from the section marked "HEAVY DUTY TRAILER TOW"

"this style oil cooler is an external oil-to-air type mounted ahead of the radiator (Fig. 8). This style cooler uses rubber oil lines to feed oil from the internal cooler to the external and then to the automatic transmission."

3) Carl claims that: "Having the fluid leave the cooler at the top ensures that it will be warm enough to allow the transmission to function properly"

Let me point out that on a cold winter morning that the thermostat in the cooling system is CLOSED until the engine warms up. This can take some time in the winter, upwards of 5-10 minutes. During this time the water in the radiator is NOT circulating, thus it is cold, thus the radiator is not "making the trans fluid warm enough to allow the transmission to function properly" no matter which way the fluid lines are plugged in.

Carl does have a point that temperature affects the fluid characteristics, and this has an effect on the transmission. But Chrysler also knew about this. As a result the trans computer decides shift points based on a number of factors ONE OF WHICH is ENGINE COOLANT TEMPERATURE, NOT TRANSMISSION OIL TEMPERATURE. This is discussed on page 21-60 of the FSM.

The trans computer will not allow the trans to go into overdrive until the engine coolant temperature is high enough. That is why it takes forever to upshift on cold winter mornings.

The only thing that all this might indicate is that if your regularly driving in sub-zero temperatures you might think twice about adding an external transmission cooler.

I will go further and state that there is a myth that trans fluid must be 'hot.' My guess is the optimal range is just high enough so that any water that gets in the fluid rapidly evaporates, and that the trans housing is warmer than atmosphere, so that condensation does not form. But even 100 degrees is plenty hot enough for this. Trans fluid does not have combustion gasses passing through it, so there is no introduction of varnishes and other gook that will jam up valves and such, where that stuff will be boiled off if the fluid is up at 200 degrees so you have an advantage of it being hot.

When many materials espically aluminum are heated they get softer and weaker, and the shearing effect in the trans torque converter is a heat generator anyway.

Many people have said in many forums how when front wheel drive became popular that transmissions didn't have the lifespan they used to - I wonder considering that in a FWD car the trans is in the engine compartment, not hanging off behind, if some of this is due to an average increase in temperature of the transmissions.

In my 41TE, there are two cooling oil fittings on the side of the tranny facing forward, one is from the tranny and the fluid comes out there, (I'll call it the output) the other goes back to the pan and the fluid is returned there. (the input) The input is the port CLOSEST to the engine, the output is the FURTHEST from the engine.

On the radiator, there's a transmission cooler which is immersed in the vertical tank on the drivers side of the radiator - it also has an input and an output port. On this cooler the input is at the TOP and the output is at the BOTTOM. The reason for this is that the water in the radiator at the top is hotter - because the top radiator hose from the engine is the cooling water output on the engine. Water in the radiator flows from top to bottom, the water at the bottom is the coolest and so for maximum heat transfer you want the tranny fluid exiting the tranny cooler in the radiator where the radiator is coldest.

For stock setups, the output port on the tranny, furthest from the engine, is plumbed to the TOP of the radiator tranny cooler, and the BOTTOM of the radiator tranny cooler is plumbed to the tranny input line - closest to the engine.

Now, my T&C had the "factory towing" package on it (it's a dealer-added item) which consists of a Mopar trailer hitch, 2 leaf helper springs added to the rear springs, and an auxiliary transmission cooler. The cooler was plumbed in series with the radiator tranny cooler thusly - instead of the output line from the radiator tranny cooler at the bottom going straight back the the tranny, it went to the auxiliary tranny cooler then from there back to the tranny input. This is so that the fluid can be further cooled after exiting the radiator tranny cooler.

If these lines are reversed, as they were in my van, with the output line from the tranny connected to the auxiliary cooler and then to the bottom of the radiator, the tranny fluid exiting the top of the radiator tranny cooler with be much hotter, and in addition the cooling of the auxiliary tranny cooler could even be completely negated.

Two more pieces of advice. First, the speed at which the tranny pumps out fluid is very rapid, probably a quart every 10-15 seconds. Use a funnel that has a neck that is almost as wide as the dipstick - you're going to be dumping fluid in there as fast as it will pour out of the quart bottles.

Lastly, KEEP TRACK OF YOUR FLUID VOLUMES! What I did is I vented the old fluid into plastic oil pans. I used a milk jug and repeatedly filled it with water and emptied it into the plastic oil pans then used white paint to make gallon marks on the inside of the oil pans where the water level was. (obviously I then dumped the water out) This way when the tranny was in Neutral and idling and fluid was pouring out of the output line into the plastic pan, I could easily look down through the engine compartment and see the paint marks on the pan and get a idea as to how fast I needed to dump the new fluid into the dipstick.

Chrysler - Dodge - Plymouth automatic transmission adjustment

Jafscar wrote:

On the (three-speed) A413s, that there are 2 bands that all the books recommend be adjusted during fluid changes. One is easily accessible from outside the transaxle casing and in fact can really be adjusted at any time. The other one (low-reverse band) is much more problematic in adjusting since it requires removal of the transmission oil pan to access and MAY also require removal of the filter, parking rod e-clip and parking rod in order to gain sufficient clearance to adjust.

In addition to this it also requires the use of a precision torque wrench since that the books state the inner bolt has to be tightened to 41-inch lbs before backing it off the recommended number of turns and tightening the lock bolt down to its specified torque.

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