Transmisssion i have a 94 850 my transmission up lite & mode switch will flash and the car feels like it"s driving in low gear,i was 50 miles from home i drove home. the next day i was going to take it to the shop nothing was flashing and driving normal.what"s up

Transmission may now be toast since you continued to drive it when maybe low on fluid or torque converter had failed. How long since last fluid and filter change? Ever?

The usual cause of this is a bad PNP switch or gear position sensor.
The "W" is flashing because the transmission control module is stuck in the Winter mode. If you are not familiar with sensor, I suggest you go and have the transmission codes read and reset to begin with and then post back the results.

Transmission is failing the reverse gear has proved it. This is why the reverse is second gear in a automatic transmission that why at times if it can get pass second it can accelerate and go fast if it cant get past second then it slips as you drive, your second gear in this transmission is failed if you need to prove to yourself that the transmission has failed look at the transmission fluid my friend it is blackish or black it is burnt, leave the turbo out of the picture there is nothing wrong with it. as for the injection pump a ck engine light will appear and the code will be a lean bank EGI failure. leave the pump out there is nothing wrong with it. you transmission look at the fluid it burnt transmisssion has failed and is slipping

if your lucky, its just a u-joint going out.

try replacing the u-joint which connects the driveshaft to the rear end(differrential), and if that does not solve it, then have your differrential checked out (a bad differential usually wont get all the power to the wheels that its supposed to) or just have it replaced, possibly with a junked differrential form a wrecked vehicle with low miles.

My 2000 ford expedition XLT 4.2 L V8 overdrive lite is flashing as well took it in they said I need a new transmission so I are they can't put in a new overdrive thing my trucks rpm go high ones I'm over 45 it starts flashing and rpm go up but no power almost like it puts itself in neutral anyway I have to put in in drive 2 then switch back to drive to have power again as long as I stay under 42 miles an hour it drives fine over that speed overdrive light flashes and rpm are wakey lol I don't know anyone have a idea I don't want to put in a new transmission please help it's the only car my family has thank you

I would suggest a service of the automatic transmission where the filter will be cleaned, bands tightened and new transmission fluid put in. the autotransmission is often forgotten about in our car servicing.
Good Luck

How many miles are on the transmission?? It sounds like there is low pressure going to the overdrive clutches or the electronic valve body controller in the transmisssion causing the flashing od light. Pretty typical. The fix would be have the transmission scanned, and it should narrow it down for you.

You need to have it checked out by a mechanic as soon as possible, I drive a 2000 cadillac catera and it began to have the same problems about 4 months ago but last month my sport mode button began to blink which means a transmission problem. So when i had it looked at they said my 3rd gear was almost completely burnt out and it cost $2,000 to fix. The cause was a broken piece of the transmission was failing and it had to be completely rebuilt. Good luck!!

Your trans is going into limp mode and that is why it is starting out in a higher gear.With the o/d light flashing there is a problem.Try this disconnect the battery for 5 min then start the car,before you do anything cycle the o/d button and see if it starts flashing.If it does then there is somekind of electrical problem.Could be bad wire or bad solenoid.If not drive it and start out with o/d off in low and shift manually through the gears and see if they are all there when you need to get in fourth hit the o/d button to shift and see if it does.They should also be able to get a code for the flashihg light to try to pin point.Hope this helps and thank for using fixya

well.. the output speed sensor is the output side of your transmission speed sensor... these are horrible on merc's... easily replaced... but a pain to get the correct one.. and this sensor could cause almost all the problems you list alone... but with such low miles it may be a warranty item? as it is on your transmission...