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Lane MacFarlane wrote:

I changed the fluid and filter, and adjusted the bands on our 85 Voyager (2.6L, A470 3-speed auto trans, 118K mi)...the fluid was no longer bright red, but sort of tired dark reddish brown. No burned smell, no flakes, no particles, so that's good! I suspect (being the second owner I have no way of knowing, but) this is the first trans fluid change it's ever had. It was time!

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 trans design, and if you can do a valve cover gasket on an OHC 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! 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 FSM 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 on the Veeger) for the filter screws. Note that the fastener sizes quoted are for the 85 A470, other years may be diferent.

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). Use that new high-quality black RTV for the pan gasket, not the cheapo stuff.

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 trans fluid out. I had a leak in the diff 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 the RTV seal better. 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 diff 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 RTV (especially on the diff cover). Above all else, keep the insides of the trans clean, no lint. Put in the recommended quantity of fluid (4 qts US for the 85 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

James Bottger wrote:

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.

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 may have to be put into "Neutral" or "Drive" in order to pump the fluid from the transmission. I usually put mine in "Neutral" to accomplish this step. While the transmission is pumping out fluid, you can monitor approximately how much fluid has been pumped out by looking at how much fluid has been pumped into the plastic milk jug. While fluid is being pumped out, slowly add new fluid to the transmission at about the same rate as its being pumped out. This keeps the fluid level at, or near the proper level. You can see the condition of the fluid through the clear tubing as its being pumped out.

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!

Additions

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.

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.