Chrysler Repair: ATX vs.ETAX transmission in Caravan 2.4L, electronic control systems, caravan 2

Question
Hi, Can interchange transmission a604 dodge 2002 caravan 2.4l with the a413? And what am giving up; mileage, torque, and maybe general electronic or drive smoothness, wise?
thx,
Mark

Answer
Hi Mark,
The ID terminology of the two transmissions for '02 is 31TH or 41TH (formerly A-413 or A-604) so keep that in mind.  The final drive gear ratios are different (1.00 vs. 0.69), and for that reason the engine will turnover 30% more rapidly at a given mph using the 3-speed, so less gas mileage. You can 'experience' what it would be like to change to the 3- by not using the OD position on your ETAX while on the highway as that is like 3rd on the 3-speed, i.e. it is also 1.0 ratio,  Probably also would have better starting acceleration/torque with the 4 as compared to the 3 (lower ratio in 1st gear only). Ideally the 4-speed is more smooth if it is working properly given the electronic control systems. BUT, the reliability/miles before needing re-build is probably better for the 3- than for the 4-speed. If you are contemplating putting the 3- in a mininvan that now has the 4- I would be concerned that you may have some other considerations: pcm will probably need to be changed out due to different internal programming, the range switch plugs on the transmissions are not identical so that would have to changed/spliced, and there may be other subtle wiring issues that can't be anticipated. I would be inclined not to do it even though I prefer the 3- because it is less problemmatic repair-wise than the 4-.
Roland