Good day all,

Having some issues with the 4r100 in my 99 EB Expedition.
When cold the transmission shifts fine, once warmed up there is a light slip in 1st gear. takes about 1500 rpm to go. If i go 1st gear on the shifter it acts totally fine no slipping at all.

Any insight to why this is happening? fluid is at proper level, color good. is it possible flush and filter would help?
Servicing of fluids has always been kept up.

Thanks for any help!

edit to add: OD light is not flashing

 

Got it figured out. Transmission is toast. Dropped the pan, metal on the magnet, fluid going black, flush was done 10 k ago and it did not look like this. Time for a new trans, this one made it 375,000 km.

Thanks for the help.