Sudden, total loss of all gears.

[SoHK_alumni]

A bit out there, but I've a friend who was diving to work, 2006 F150 with a 4R75E transmission.

On the highway and experianced sudden engine redline. No warning, no unexpected noises, vibration, nothing.

Pulled to the side of the road, and has nothing. No drive, no reverse, -- oh, Park works perfectly but there is absolutely no attempt at movement. Fluid level is correct, fluid is still clean, clear and bright red.

Closest Ford dealer is saying total transmission failure, $5400 to repair.

Any ideas on what could fail and cause such a total, complete and instant failure?

 

[JK080]

To lose both forward and reverse at the same time leads me to believe that there is no line pressure, the main reason for that would be pump failure. Pump failure on this transmission is not all that common but it does happen.

To conform check the transmission fluid with the engine off, the fluid level should be high on the stick. Then check the fluid with the engine running, the level should drop to the full range. If no difference between engine running and engine off tell us that the pump is not pumping fluid and without fluid pressure nothing in the transmission will work.

You should be able to have that fixed for half of that cost at the dealer.

 

[SoHK_alumni]

Thank you for the ideas.

I'm getting the F150 tow across state so I should get hands on in the next day or so.

I'd known it nearly had to be total hydraulic pressure failure, but had never seen a pump simply give up like that. Then again, I've never seen any auto box fail this way.

My gut tells me I'll be pulling the transmission but if its as simple as the pump, that might make it a viable repair candidate rather than a "must rebuild/replace" candidate.

Shoot, I still have faint hopes that it's something as simple as a loose electical plug. I've such low expectations of the dealerships that I'd have no surprise if I were to find the solenoid pack has simply become disconnected from the PCM despite the formal diagnosis.

 

[imp]

Thank you for the ideas.

I'm getting the F150 tow across state so I should get hands on in the next day or so.

I'd known it nearly had to be total hydraulic pressure failure, but had never seen a pump simply give up like that. Then again, I've never seen any auto box fail this way.

My gut tells me I'll be pulling the transmission but if its as simple as the pump, that might make it a viable repair candidate rather than a "must rebuild/replace" candidate.

Shoot, I still have faint hopes that it's something as simple as a loose electical plug. I've such low expectations of the dealerships that I'd have no surprise if I were to find the solenoid pack has simply become disconnected from the PCM despite the formal diagnosis.

@SoHK_alumni
JK might disagree with me, but in the event there is no pump out, no pressure, bear in mind that a mechanical failure between the engine and the pump, would cause no pressure. Possibly a broken transmission input shaft, which drives the pump. imp

 

[JK080]

A bit out there, but I've a friend who was diving to work, 2006 F150 with a 4R75E transmission.

On the highway and experianced sudden engine redline. No warning, no unexpected noises, vibration, nothing.

Pulled to the side of the road, and has nothing. No drive, no reverse, -- oh, Park works perfectly but there is absolutely no attempt at movement. Fluid level is correct, fluid is still clean, clear and bright red.

Closest Ford dealer is saying total transmission failure, $5400 to repair.

Any ideas on what could fail and cause such a total, complete and instant failure?

This transmission will go into reverse and have a forward gear even with all electronics unplugged so you can rule out any electrical item causing this condition, do the test with the fluid level. If the pump has failed and there is little debris in the pan you could just replace pump and its relatively easy repair, also make sure you check the converter hub for damage due the damaged pump gear, it's probably damaged and you will need to replace the converter as well.

@SoHK_alumni
JK might disagree with me, but in the event there is no pump out, no pressure, bear in mind that a mechanical failure between the engine and the pump, would cause no pressure. Possibly a broken transmission input shaft, which drives the pump. imp

The only connection between the engine and pump is the flywheel and converter outer shell and the converter hub, if the input shaft was broken or stripped out the pump would still work but the vehicle wouldn't move. So when he does the fluid test that I suggested he will find out if the pump is broken or the input shaft is broken or stripped, either way its broke.


Here is how the pump gear fits on the converter hub.

Here is what a failed pump gear to hub looks like. you can see where the converter hub was driving the gear when it stripped.

This particular failure was due to a replacement converter was machined incorrectly and the overall height of the converter was too low and wasn't fully engaged into the gear like the first picture.

Correct height converter on the left.

 

[SoHK_alumni]

Well, the plot thickens:

Got the F150 dragged across the state and had some brief hands on with it.

Stone cold, fluid level seems high, not as "clean" as I'd been told. Fluid is well above the "Cold" level mark. Unlike on the side of the road when at temp, there is sluggish movement when in drive or reverse. Have not tried to drive it.

Seems to have a whine in the pump, similar to when a power steering pump is low on fluid and is cavitating.

Hoping to get the transmission drained tomorrow and the pan off to get a look at the "outsides" of the internals.

Looks like an over the counter rebuilt transmission is about $1200, a far more palitable cost than Ford's estimate, even after the couple hundred for the tow.

 

[imp]

This transmission will go into reverse and have a forward gear even with all electronics unplugged so you can rule out any electrical item causing this condition, do the test with the fluid level. If the pump has failed and there is little debris in the pan you could just replace pump and its relatively easy repair, also make sure you check the converter hub for damage due the damaged pump gear, it's probably damaged and you will need to replace the converter as well.




The only connection between the engine and pump is the flywheel and converter outer shell and the converter hub, if the input shaft was broken or stripped out the pump would still work but the vehicle wouldn't move. So when he does the fluid test that I suggested he will find out if the pump is broken or the input shaft is broken or stripped, either way its broke.

@JK080
Ahhh, I plum forgot about those "ears on the converter driving the pump. Stupid of me to imagine the input shaft driving the pump! Must have been "one of those days"!

Thanks for that excellent reply. Clear.
imp

 

[JK080]

Pump whine is common when the filter is clogged, a clogged filter can create a no movement in any gear.

I have seen gear train failure and converter failure with these which create a lot of debris and can clog the filter.

Drop the pan and see whats there.

 

[SoHK_alumni]

And the verdict is in:

165K miles, two transmission services and the friction plates wore enough to clog the filter.

Once pressures dropped, the frictions went bye bye in a hurry.

Odd thing, front drum ate the heck out of the stator so there was quite a bit going wrong in there.

Should have it back together and on the road for its trip home this weekend.

 

[JK080]

DId the snap ring come off the front drum? I would recommend a spiral ring to prevent the snap ring from coming off either way, its a common failure.