Because of the design, the computer changes the shift "personality" as the clutch plates wear over time. That results in a nice crisp shift until the day comes when it can't update any more. That's when it goes into "limp-in"mode and stays in second gear. You don't have any warning that is about to happen like we did many years ago. Those older hydraulically-controlled transmission would slip a little between shifts and those shifts would feel mushy for a year or more, so you had lots or warning unless there was some catastrophic failure. That can happen with yours too but sensor problems and clutch plate wear are the more common failures. There is one way an experienced transmission mechanic can tell about how much life is left on the clutch plates. By using the Chrysler scanner, it can read out the "clutch volume index", (CVI). That is a set of four numbers corresponding to the four clutch packs. It is the number of ccs of fluid volume it takes to apply each clutch. As the fiber plates wear down, it takes more fluid volume to fill in behind the pistons until they're fully applied. The computer constantly updates those numbers and uses them to calculate shift timing. As an example, after many miles and wear, it will apply third gear a little sooner to give it time to lock up before it releases second gear. That's what keeps the shifts feeling like when it was new but it also removes the sensation that wear is occurring. Keep in mind that even when you know that, it's only an indication of about how much wear has occurred so far. Parts could break unexpectedly or a sensor could fail. Those same things could happen with a replacement transmission. If you're concerned with the dollars, you're better off sticking $2000.00 in a savings account and just keep driving until the need arises. If you do a lot of highway driving where not much shifting is taking place, those clutch plates could last a long time. No sense inviting trouble by installing a different transmission that is "an unknown quantity". It could have more trouble than your old one.
Thursday, March 10th, 2011 AT 11:19 PM