Dodge, Chrysler, and Plymouth Three-Speed Front-Drive Automatic Transmissions
Overview (by Ed Treijs)
The key advantage of the A413 automatic transmission is that it is reasonably light, simple, and durable (at least in the lower-powered applications).
The drawback is that we only have three gears, which is fine with bigger 6 and 8 cylinder engines, but not so hot with even the "big" 2.5.
You can make first geer deeper, but then the 1-2 gap becomes even more troublesome. Another thing is that durability is inverse of gear multiplicaton; so a 3.3:1 first gear requires stronger construction to last as well as a 2.7:1 first gear.
I changed from 205/50-15 to 195/70-14 on the Reliant. The change in diameter is about 7.3%, or about the difference between a 3.02:1 and a 3.24:1 final drive. With the short 15" tires the car felt pretty quick, especially in first from a 10 km/h roll. Lower overall gearing would help the feel of the cars, but then economy decreases, and the 2.5 isn't happy to be revving either—highway driving wasn't too much fun with the short tires.
I like the lockup feature very much. In fact I will sometimes go, umm, somewhat over the limit to engage it (at exactly 61 km/h indicated; in reality this is more like 71 km/h with the tall tires). The car needs less throttle pressure (at least as far as I can tell) to go down the road at 63 km/h with the converter engaged, than at 59 km/h with the converter unlocked. What I'd like to see is a looser, higher-stall converter combined with a more aggressive lock/unlock schedule.
As for shift quality, I wish someone made a shift kit for the lockup transmissions (the Mopar Performance unit is "not for lockup converter applications"). What's with the dying-moose lurch between gears? Sure you can get firmer shifts by adjusting the throttle control cable, but I suspect that works better on 2.2s than on 2.5s. I drove around with late upshifts for quite a while; you don't realise how annoying it is until you get proper shifts.
Repairs and maintenance
Band adjustment ("Jasfcar")
There are 2 bands that according to the manuals are supposed to be adjusted at the time of transmission fluid changes. One band is easily accessible from outside the casing. The other is the low-reverse band and requires (at least) removal of the transmission oil pan and filter (and probably also the parking rod and e-clip). Also, in order to adjust them, they require a precision torque wrench (that reads in inch-pounds, not foot-pounds).
If you don't want to tackle the complicated task yourself, have a trusted and knowledgeable mechanic do it for you (ideally at a Chrysler dealership).
You might want to try this. Pop the hood and with the engine idling (parking brake set and with foot firmly on the brake) shift it in reverse. If your motor pivots/jerks violently this very well could be your problem. (You should be able to see what the motor does through the crack under the hood.)
Adjusting shift points (Jeff Chojnacki)
You can adjust shift points by adjusting the spring and cable on the top of the trans. All you need is a small flat blade screwdriver. Confusing the first time you try to do it, very easy later.
Delayed shifting (Darryl)
[a] broken or missing return spring on the kickdown rod ... will hold off 1-2 for a long time, and when it finally occurs, you feel as though you were rear ended by a freight train.
Greg Perman: more on the effects of the missing return spring on the kickdown rod
This missing spring caused shift points to become too high for 1-2 and 2-3 upshifts on my 3.0L, 3 speed Caravan (1-2 upshift point went up to about 17 MPH, and 2-3 changed to 35 MPH and higher). Service manual says speeds should be 13-16 MPH for 1-2 and 17-21 MPH for 2-3 upshifts.
One end of this spring attaches (next to the PCV hose) to the metal clip bolted to the air intake plenum. The throttle/speed control bracket supports a 1/4" or so diameter u-shaped link, which in turn supports the kickdown rod. Attach the other end of the spring to this u-shaped link where it meets the kickdown rod (where it rides in between the u-shaped bend at the top of the kickdown rod, not the KR itself).
Greg Perman: “slipping, shuddering”
Our three speed automatic transmission sometimes seemed like it was slipping when starting off from 0 MPH- it was actually starting out in second gear-you can check with car stopped, foot on brake with Drive selected.... then, select first gear with column- if you feel your trans shift, it isn't ready to start off in first...also good to see if car upshifts from 1-2 and 2-3 at correct speeds during normal driving around.
I also had heard an occasional shudder, only under acceleration, around 40 MPH or so... Though the trans fluid was at normal level and looked pretty clean, a trans mechanic pulled the pan and found metal build-up around the magnet, dirty clogged filters etc. A change of trans fluid and filters completely eliminated slip and shudder symptoms. Two trans mechanics before this said I needed a rebuild. Might be good to get 3 opinions!
Fluid change notes (Ed Hennessy)
The older (RWD) Torqueflites [drained the transmission fluid out of the torque converter] as a matter of design, though it usually would take 3-5 days minimum to drain out. On those transmissions, the pump does not run when the transmission is in park, but it does in neutral. The trick on these, which I use on my '78 Volare with A904, is to start it up in neutral and let it run for 30 seconds to a minute. With it in neutral and by waiting, the pump circulates fluid and fills the converter. Then you put it in gear, and off you go. If it's drained and you start in park and drive right off, the transmission is sluggish.