I have a 2001 Discovery with 120,000 miles on it.When engine is cold my trans slips in and out of gear sometimes .Summer only for a minute or so but in winter it takes longer to work properly.After it warms up works just fine.This has been going on for 3 years.Had the truck for 7.It is noticeable if I am driving slowly around town but if I am driving fast right off not as bad. Changed fluid and dropped pan twice and all looked good;the last time was last year.The only transmission place anywhere near me has no way to check sensors.Any suggestions?

 

Transmission fluid expands when it gets warm. It sounds like your Transmission fluid may be low. It may be slipping when it's cold because the fluid is too low and then works better as the fluid gets hot and expands.

Are you filling the transmission fluid up with the engine off and then starting the engine to finish the fill up? Some people forget to fill the transmission while the truck is running.

The last few quarts need to be filled up as fast as possible before the fluid has time to get warm. If you let it get to hot while filling then it may look full but really be a quart or two low.

 

Do you have a service engine light on, if so what are the fault codes, when you changed the ATF, what color was the fluid that came our, how many quarts did you use when refilling it and was the motor running when you refilled it?

 

Trans fluid was filled on a lift with motor running and going through the gears.Fluid was clean as a whistle and pan and filter had no particles in it last time changed.Service Engine light goes on and off periodically but nothing comes up on scan.Put a new gas cap on and only comes on very seldom now (and goes out on its own)Dont remember how many quarts ,didnt pump it out just drained the pan.

 

You need to read the code the next time the light comes on, sound like you will probably find one of the 700 codes related to the tranny.

 

What can that mean Mike,or are there too many variations to venture a guess?

 

My transmission did this same thing yesterday.
DII had sat for three weeks.
Started it.
Went to drive - nothing.
Went to reverse.
Went to drive again - had power at wheels.
I bet the fluid drained out of the torque convertor.

 

Well the dirt hit the fan today .Trans shifting in and out .Mode lights and drive indicator on shifter flashing and thelittle yellow rover light going uo the hill with! and TC lights on HELP!

 

Pull the transmission codes with a Scanner.
Even my old scanner notices the transmission.

 

Were you towing stuff in the past?