Q: Transmission slipping even when I had the transmission replaced.

asked by on January 04, 2017

In November, I tried to drive my Jeep with the heater on and it caused the transmission to slip and not shift past 2nd. Keying it on and off would sometimes help. I had a mechanic put in another transmission and it worked fine for a week, but it is slipping and going into limp-in mode as well. The exact same behavior.

OBD2 is only throwing codes for both 02 sensors not working. There are no codes at this time for transmission sensors.

Notes: My battery is really old. I have to float charge it a lot and sometimes it won't work at all unless I really push on the brackets, which are totally clean. Neither of my O2 sensors work. Sometimes it shifts fine, then falls back to this problem. Sometimes adding slack to the TV cable lets it shift, but the shifts are too early and too smooth for safe driving.

I don't believe the transmission has any issues mechanically. It has been fully tested and maintenanced.

Can the bad 02 sensors cause this? Can the weak battery be causing this?

My car has 160000 miles.
My car has an automatic transmission.

Hi there. If the transmission was slipping and you had the transmission replaced and the transmission is still slipping, then there could be an issue with the shifter cable or downshift cable. Check the cables and see if they are adjusted properly. If you had adjusted the shifter cable a little tighter and the transmission begins to shift and not stay in second, then I recommend replacing the shifter and downshift cables and adjust them to the correct setting. If you need further assistance with your transmission not up-shifting, then seek out a professional, such as one from Your Mechanic, to help you.

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