I need help, i had my OD light flashing and was told it was a sensor so I changed both sensors on the transmission and the one on the diff, now before I changed these sensors I had no CEL. Now that I have changed the sensors I have a CEL and it doesn't shift gears like it should. I'm not sure what to do or where to start. Any help would be great thanks!

 

You need to have the codes read and tell us what the codes are depending on what type of scanner they have the auto parts stores loaner ones may not be able to read trans codes which is what the od light flashing means that there are transmission codes. Some say that no auto parts store scan tools can't read trans codes but I have used one that did and also could cycle the abs. Most of the chain repair shops like firestone at least here will read your codes for free too and they have better scan tools. Are your sure you got the sensors and put them in the right places and that the connections are clean and tight. With out the codes there's nothing anyone can do but guess a replace parts and hope you get lucky.

 

The code was p0720, it said it was the sensor in the tail end of the transmission. The OSS fault was coming up in the scanner, so i I replaced it again today and the check engine light has gone off for now! The OD light is still flashing so I need to get that code read asap to figure out what that can be. I'm learning all this as I go which is not easy at times but I must say I'm learning alot quickly!

 

Sorry I double posted

 

You have to learn that fault codes do NOT mean the part mentioned in the code is bad, the code means that computer has a problem with the signal from that sensor. There is a profound difference.

 

I understand there is a difference, but the sensor was bad so changed the bad sensor and the CEL has gone off and stayed off......now for the OD light I will need to dig a little deeper to see what is going on.

 

You need to find someone with a scanner that can read transmission codes, anything else will be guesswork otherwise.

 

The distinction is that the scanner must be able to read "manufacturer-specific" fault codes, check the specifications. A scanner that only reads "generic" codes will probably not be adequate.

 

And some of the transmission codes are defined as generic, though the vast majority are not generic codes.

 

... and there seems to have been a somewhat gradual movement of those codes from generic to mfr-specific early in the last decade as the operating system software evolved from, for example, non-CAN to CAN and, in the case of non-green state >8500 GVWR vehicles, from OBD-I to OBD-II calibrations (finally).

 

Most transmission shops should be able to read these code?

 

A good transmission shop should have that capability.

 

I will find a good one and have them read the codes, then take it from there! Thank you