Hello folks. I thought I would gather up and post all the information that I have regarding 3rd generation transmission swaps, as it seems to be a topic of frequent inquiry. I have done the 2004 Caravan 3.3L into a 1996 Voyager 3.3L, so I can vouch for these model years. I do not know if any of the newer 2005 and onwards will work.If anybody has anything to add, feel free.
General Information: Transmissions are interchangeable in these vans from 1996-2004 when dealing with the same engine to transmission combination within the same vehicle line (ex 2004 Caravan/Voyager/Town & Country 3.3L to 1996 Caravan/Voyager/Town & Country 3.3L). In mid 1998 a change from round pins to flat blades in the transmission range sensor connectors was made to increase the reliability of signals to the TCM. This necessitates an adapter or cutting off the old range sensor connector and soldering on the one from the salvage transmission when installing one of these newer transmissions in a 1996 to early 1998. If the transmission has already been pulled without it's connector, ask for it. Otherwise you will need to purchase an adapter from a transmission shop. Electrically, the connector pin outs are the same. Just the wire color coding and pin shape is different. Match the wire on the old connector pin to the same position pin on the new connector, then solder the new pin's wire to the wire on the vehicle harness with the color code that matches the old connector. It is also possible to swap the old transmission range sensor into the new transmission by dropping the oil pan and the valve body, negating the need for any soldering or an adapter BUT it will sit much lower in the transmission case. So much so that it will not seal properly as designed. I attempted this initially, but opted to switch back to the proper transmission range sensor and solder on the newer plug. Too much danger of water infiltration (very bad) into the transmission in my opinion.
Regarding physical installation, on the 1996-1997's the flexplate has one 'D' shaped hole. If you install a newer transmission in one of these years, this hole will need to be ground out to round like the other three or, you can get a newer flexplate. Either salvage or aftermarket will suffice. 3.0L transmission's have a custom bell housing that only mates with that engine. Watch out for dowel pins. Sometimes they fall out, other times they stick in the transmission. This is a problem when BOTH the transmission and engine have dowel pins in them! Pull the pins out of one or the other before installation, it doesn't matter which. Just be sure to only have one set of dowel pins to guide the engine and bell housing together. Fluid dipsticks usually need to be swapped out for the older ones when putting in a 2001 or newer transmission. Also, there is an extra bolt boss on the 2001 and newer transmissions. Just ignore it and use your old transmission mount. Now would be a good time to replace it if yours is deteriorated.
Internally, there are differences mainly between different carlines and engines(Stratus, Caravan, Intrepid, 3.3L vs 3.8L, etc) Mostly in the final drive ratios and things of that nature. Generally it is more work than it is worth, in my opinion, to change out with a different carline or engine. Your best bet is to stay with what you have. Not really a problem since the vans are popular and plentiful in salvage yards. But if you are really determined, knock yourself out!
Electrically, the only differences are in the TCM programming from year to year. Things like torque converter clutch modulation, shift points, etc. It is NOT necessary to reflash or replace the TCM module with the one from the salvage donor vehicle unless you want the transmission to shift with the same characteristics. In some cases, this could even cause problems. You can just leave the battery unplugged for a day or so to erase the old adaptive program for the previous transmission. All this means is that your newer transmission will be running an older shift program, with the attendant shift points and torque converter lockup clutch behavior as programmed in that model years' TCM. Yes, following installation you can Quick Learn the TCM Clutch Volume Indice's (CVI's)if you are so inclined and equipped (Chrysler DRB III, Chrysler Star Scan), but you don't have to do it. Otherwise, not Quick Learning means the transmission will shift oddly or a little rough for a while until the TCM is able to create a new adaptive profile for your driving style. Third generation TCM's are VERY adaptive, perhaps too much so, since Chrysler toned that down greatly in successive generations. But it WILL smooth out shortly, don't worry.
Other things to watch for include using ATF+4 or newer fluid ONLY. Change the old filter in the new transmission. Before installation is also a good time to change all the oil seals. Nothing like finding a leaking torque converter or CV shaft seal AFTER the transmission is installed. Oh what a feeling.
General Information: Transmissions are interchangeable in these vans from 1996-2004 when dealing with the same engine to transmission combination within the same vehicle line (ex 2004 Caravan/Voyager/Town & Country 3.3L to 1996 Caravan/Voyager/Town & Country 3.3L). In mid 1998 a change from round pins to flat blades in the transmission range sensor connectors was made to increase the reliability of signals to the TCM. This necessitates an adapter or cutting off the old range sensor connector and soldering on the one from the salvage transmission when installing one of these newer transmissions in a 1996 to early 1998. If the transmission has already been pulled without it's connector, ask for it. Otherwise you will need to purchase an adapter from a transmission shop. Electrically, the connector pin outs are the same. Just the wire color coding and pin shape is different. Match the wire on the old connector pin to the same position pin on the new connector, then solder the new pin's wire to the wire on the vehicle harness with the color code that matches the old connector. It is also possible to swap the old transmission range sensor into the new transmission by dropping the oil pan and the valve body, negating the need for any soldering or an adapter BUT it will sit much lower in the transmission case. So much so that it will not seal properly as designed. I attempted this initially, but opted to switch back to the proper transmission range sensor and solder on the newer plug. Too much danger of water infiltration (very bad) into the transmission in my opinion.
Regarding physical installation, on the 1996-1997's the flexplate has one 'D' shaped hole. If you install a newer transmission in one of these years, this hole will need to be ground out to round like the other three or, you can get a newer flexplate. Either salvage or aftermarket will suffice. 3.0L transmission's have a custom bell housing that only mates with that engine. Watch out for dowel pins. Sometimes they fall out, other times they stick in the transmission. This is a problem when BOTH the transmission and engine have dowel pins in them! Pull the pins out of one or the other before installation, it doesn't matter which. Just be sure to only have one set of dowel pins to guide the engine and bell housing together. Fluid dipsticks usually need to be swapped out for the older ones when putting in a 2001 or newer transmission. Also, there is an extra bolt boss on the 2001 and newer transmissions. Just ignore it and use your old transmission mount. Now would be a good time to replace it if yours is deteriorated.
Internally, there are differences mainly between different carlines and engines(Stratus, Caravan, Intrepid, 3.3L vs 3.8L, etc) Mostly in the final drive ratios and things of that nature. Generally it is more work than it is worth, in my opinion, to change out with a different carline or engine. Your best bet is to stay with what you have. Not really a problem since the vans are popular and plentiful in salvage yards. But if you are really determined, knock yourself out!
Electrically, the only differences are in the TCM programming from year to year. Things like torque converter clutch modulation, shift points, etc. It is NOT necessary to reflash or replace the TCM module with the one from the salvage donor vehicle unless you want the transmission to shift with the same characteristics. In some cases, this could even cause problems. You can just leave the battery unplugged for a day or so to erase the old adaptive program for the previous transmission. All this means is that your newer transmission will be running an older shift program, with the attendant shift points and torque converter lockup clutch behavior as programmed in that model years' TCM. Yes, following installation you can Quick Learn the TCM Clutch Volume Indice's (CVI's)if you are so inclined and equipped (Chrysler DRB III, Chrysler Star Scan), but you don't have to do it. Otherwise, not Quick Learning means the transmission will shift oddly or a little rough for a while until the TCM is able to create a new adaptive profile for your driving style. Third generation TCM's are VERY adaptive, perhaps too much so, since Chrysler toned that down greatly in successive generations. But it WILL smooth out shortly, don't worry.
Other things to watch for include using ATF+4 or newer fluid ONLY. Change the old filter in the new transmission. Before installation is also a good time to change all the oil seals. Nothing like finding a leaking torque converter or CV shaft seal AFTER the transmission is installed. Oh what a feeling.