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02 Ford Taurus transmission quit

My daughter was driving 02 Taurus and transmission just quit. I checked fluid with car off and then started and went thru gears and rechecked, and fluid went down to operating range. So I assumed torque conv and pump were working. Towed it home and has been sitting for a month. Started it today and it moves in all gears. Anyone know what was/is wrong with it. I plan on changing trans filter and fluid. Any ideas of what else to do to it? Thanks

How many miles on the car?
How many miles has it been since the transmission fluid was changed (if ever)?

The AX4N/4F50N transmission is not known for being being particularly reliable. If the transmission fluid/filter has never been changed up to this point, then the odds are not great concerning the transmissions future viability. Even with changes every 50k miles, these transmissions don’t always make 150k miles, with less frequent changes, it’s reasonable to expect less.

135,000. Not sure if it’s ever been changed , I know it hasn’t in last 20,000 anyway. Is there anything else I can do besides change fluid and filter or is that pretty much it? Or just hope for the best

That’s all you can do

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At this point that’s all you can do. If it works, great. But if it doesn’t, be prepared to part with around $1.2k to $2k for a salvage or rebuilt transmission, or another car.

it Starts and runs but really shudders in any gear, and a little in park and neutral. A month ago when it quit moving the engine ran fine. What in the transmission would make it run like this? I already bought her a blazer to drive so I’m not putting much into the Taurus, off to the junkyard if I can’t get it running good enough.

Inside your automatic transmission there’s a pump that produces high pressures, and several planetary gear-sets. This type of gear set is programmable by fluid pressure. Each of them can be in neutral, reverse, or forward w/a particular gear ratio. When they are all put in the correct configuration via their fluid pressure inputs the transmission works as intended. There’s some valves and electrical solenoids to route the output of the pump pressure to where it needs to go for that speed and engine load, in order to program the gear sets. The shift itself is effected by applying high pressure to a combination of clutches and bands connected to the gear sets, which puts gear set into the correct mode. The common failure modes are

  • the pump doesn’t produce enough pressure, usually due to failing seals
  • the valves fail b/c they stick or b/c their seals fail
  • the clutches wear out and slip
  • the bands wear out and slip
  • one or more of the electrical solenoids fail

A common test a transmission shop uses is to measure the pump output pressure in each gear. The result is usually quite helpful towards the diagnosis. Measuring fluid pressures at other test points besides the main pump output is also a common diagnostic method.

In yoru case I’d guess either the pump output pressure is too low to effect and hold a shift, or the clutches and bands have worn out. There’s a slight chance of solenoid failures too. Cross yoru fingers it is the latter, as the solenoids are usually replaceable. Note I didn’t say they are inexpensive to replace, but less expensive than replacing or rebuilding the entire transmission. The reason folks here suggest to renew the trans fluid at routine intervals is b/c fresh trans fluid has chemicals in it that help keep the seals, pump, bands, and clutches working.

So it’s probably to late to change filter and fluid for it to do any good

You have replaced the vehicle so why not just list as is for a price that will have it gone quickly.

That’s prob what I’ll do

I’d guess less than a 50% chance replacing the fluid and filter would do much good. But that procedure doesn’t usually cost much, and there’s still some chance it might work.