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Changing Automatic Transmission Fluid

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Changing Automatic Transmission Fluid

Voyager transmission fluid change and band adjustment

by Lane MacFarlane

I 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.

Water Plastic Plastic bottle Motor oil Fluid

I would like to encourage anyone with an A470/A413 (three speed for the four cylinder engines) 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 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 service manual 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

by James Bottger

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.

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

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).

Make sure that the parking brake is set and holding, chock the wheels, and start the engine. The transmission needs to be put into "Drive" so the torque converter fluid is changed as well. Most transmissions will only circulate fluid through the torque converter only in drive.

After around 4 to 5 quarts (obviously, if it's more than 4 quarts, you'll have to turn off 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.

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 quarts 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 hours. 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.

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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