93 Trans shifting problems

I have a 93 3.8 with the AXODE trans. The trans was rebuilt a few years ago and has very little mileage since the rebuild. The other day all of a sudden it started acting funny. It will shift from first to second but usually no 2-3 or 3-4. I say usually because the other day I drove it and it shifted fine all the way through. I pulled these codes 628, 646, 647, 648 which is excessive slippage and incorrect shifts on 2nd, 3rd, and 4th. I am thinking it might be an electrical problem, but am not sure. I really don't want to take it to a trans shop and have them just tell me it needs to be rebuilt without any diagnosis. Any insight would be appreciated.

Thanks

What was included in the rebuild? The problem you describe sounds like valve body or shift solenoid. Was there any warranty with the work that was done?

I'm not exactly sure what all was done in the rebuild. It has been too long since it was done for any warranty. It just hasn't had that many miles since the rebuild.

I dropped the pan today to rule out a clogged filter and to check the fluid. It looks as clean as the day it went in the trans. No discoloration or debris at all.

I'm trying to get my hands on a Rotunda Trans tester to check it out.

like irish said, it sounds like a valve broke on your car, or it might be the speed sensor. If the speedometer needle "sways" or "vibrates" between speeds, like moving from 45-47 when you are going 46, then it is the speed sensor, i am bringing mine in also, because of that problem (and it being off by 10 mph :naughty: [cops finally pulled me over and gave me a fix-it ticket :iceslolan ]) You might want to check the speed sensor first, it is cheaper of a fix.

Well I drove the car to work today as my truck is in the shop for body work and my wife is not too crazy about driving it to school, so she got the rental. It was fine both there and back with no missed shifts or delayed shifts. I am getting a Rotunda Trans Tester this weekend on loan and am going to hook it up to check everything out, but it sure seems like a electrical problem to me. And on the speed sensor note, the needle stays true all the time. No fluctuations at all.