BMW TRANSMISSION
 

Hi guys am Jorge from Chile,and i have Bmw 325i 2001,and the transmission have a problem,we made a scanner and says that stall speed (P0720) speed sensor ,need to repair. when the trans its cold there´s no problem at all,but it get hot few minutes later a yellow light comes of and the car bearly moves only in forward gears,the reverse its ok,.what shoul be the trouble?,where is located that sensor? any suggestions will be very apreciated.My best regards

It sounds like some of your gears inside the transmission may be ground down, once the transmission fluid heats up there isn't anything to hold the gears together. Do you know if you're leaking any fluid? May be time for a trans mission rebuild. Sadly a number of these early 2000's BMWs people neglect to flush the transmissions and when they finally do the transmission stops working because they got rid of the particles that were holding it together.

Hi and thanks for the quick one,but i forgot to mention that the scanner erase the code and the car was ok but after a few minutes later the issue and the light comes of.

To confirm, after the engine / transmission are hot, clearing the codes will resolve the issues for a few minutes?

So example.
Start Car. Drive Car. Light on. Transmission Stops. Car Stops. Clear Codes. Car go?

Exactly.

I used the site REALOEM.COM to put down a rough estimate of what your vehicle might have in it. If you look at the diagram below you can see the number 4 option being the locations for the speed sensors on the automatic transmission. I've learned that it's best to replace sensors in pairs. If you have the Automatic transmission these seem like they would be relatively easy to get to. These are the two speed sensors for the transmission. If you want to go to the site and look for your specific vehicle it could help out. Or if you want to punch in your VIN number on the site it could give a good baseline for figuring out what we are working with.

BAVAuto has the transmission speed sensors for both auto and 6 speed SMG manual.

https://www.bavauto.com/

https://www.realoem.com/bmw/enUS/sho...diagId=24_0997

At this point, I would recommend swapping the speed sensors, if your issue persist after the fact I would focus on having the transmission looked at internally. These can be swapped out without any real mechanical experience.

I do have some mechanical skills but i dont´know the location of the speed sensor,outside the trans or inside?.thanks again

Sorry ,now i took a look to the diagram great info and help,the question is, both speed sensor are the same?,if i order the sensor i have to ask for 02 units,right?

The trans is A5S325Z, ZF 5HP 19.