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42RLE's , no matter what year, should be reset with a scan tool after replacement.

Now to be realistic, many are replaced in home garages and they turn out fine, I have always reset any I have been involved with and recommend you to do the same.

There are two parts. One is a scan tool assisted "quick learn". You force the transmission to shift into all the gears to learn what the CVI's should be. CVI is the Clutch Volume Index. It is the required amount of time it takes to fill a clutch pack. If you don't do this it can shift pretty bad until the pcm learns it on its own. I really don't think this is a big deal as long as you drive it easy for the fist hundred miles or so.

The other part is to reset the torque convertor values. some times this gets done with a Quick learn and with some pcm's you need to do this separate. I feel this is more important because the torque convertor lock up clutch is not very durable. I feel that if you have a convertor that has failed and you put a new one in the shift that the pcm will perform would be a value from the worn part and could greatly reduce the life expectancy of the new part.

If you replace a PCM, Valve body, Transmission solenoid pack, or transmission assembly you should do this.

Now like I said transmissions are replaced all the time without this being done but for a small added cost after the repair is done take it somewhere and pay the $50 to do it right.
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