2007 Mazda 3 transmission was slipping so changed filter added Lucas stop slip now slips going into 3rd and stays longer before shifting into 4th?

 

I am not voting mainly because in this case I am not a DIY!
*In my world those 2 choices would never come up!

STOP.... adding band-aid fluid fixes.
FYI most of those transmission fluid conditioners will make a bad problem worse!!!

What you should have done when the transmission problem started was look at your service history on the transmission. See when the transmission was service (if ever) last.
Also when you start a thread about a concern having to do with problems, please provide service and vehicle information just like you would if you went to a dealer or independent service shop.

in this case MILES on the odometer? ...

So at this point you either go to a service shop and have them do a basic transmission filter and pan fluid service or you do it. With the pan is off you will be able to inspect both what is at the bottom of the pan , what is on the pan magnet (if there is one) and the condition of the valve body and any visual solenoids.


*ASE

 

I did take pan off and replaced filter plus 4 quarts of fluid the old fluid was dark didn't smell burnt there was some tiny metel shavings? On magnet I have only had car a few months no idea about service records but someone has taken pan off as it has no gasket just gasket maker

 

You didn't post the miles? My guess on your limited information is 150K(closer to) 200K+ thousand miles on the odometer?
However based on the limited information and that the fluid is as you described along with the slipping gears and you did not mention reverse but as one of the gears you mention uses the same clutches you have the beginning signs of your transmission is soon to fail either by not shifting in all the gears or complete no shift when you least expect it.

Either look for a *specialized transmission shop in your area and or start looking into low milage transmissions offered through out the USA that most come with a short warranty, or get and estimate to *rebuild yours . **Naturally this is based on the very basic and very limit information you posted but falls in line with a transmission failing.

**I would not recommend to do a complete fluid change at this point because it may kill the transmission?
You could send in a sample of your fluid to be analyzed but at this point I think we can be sure what will show is in the fluid for results of the sample.


ASE

 

Sorry over 200,000 reverse works and thanks I will get a used transmission

 

Try reverse when the engine and transmission are cold on a slight incline.

Don't wait to long to get a shop opinion (because they can physically test) and I would recommend to drive only in town close to home?