No forward or reverse

[ColoradoRanger]

1999 Ranger XLT 4WD Auto (5R55E assumed from year of Ranger). Engine died while driving. Coasted to shoulder. Engine restarted and runs fine but no forward or reverse. Manual manipulation of selector on tranny feels fine with detents where they are supposed to be. No leakage. Tranny fluid is good. Towed to shop, they commented on how good the fluid looks. No codes. They of course quoted a replacement tranny. When I asked they said that they did not check any pressures because that doesn't matter when you have no engagement at all, only when bad shifting or missing gears. They said since no codes it's a mechanical issue inside the tranny, not electrical or in the control system. They couldn't even tell me if the pump is working since they did no pressure checking. No clunking or noise from tranny. No RPM change when shifted into any gear. Truck can be rolled freely while in any gear but park does engage fine and locks transmission. Any help or advice on diagnosing this myself would be well appreciated. This is my son's first car and he loves it too much to let go of. I am using this car to teach him how to repair and maintain a vehicle. So far we have changed out the radiator, a heater mixture valve, brakes, the ignition coils, wires, and plugs. I am a very good mechanic but zero auto transmission repair experience.

 

[Transman304]

My first test would be to remove a cooler line at the radiator and start truck and see if you have any flow. If not, broken pump gears which is a high failure part. Let us know what you find.

 

[ColoradoRanger]

Will do Transman304. Thank you for the advice.

 

[AllanD]

While I am not an expert on auto transmissions

IT sounds to me like a dead one way clutch (This is a failure inside the torque converter)

 

[ColoradoRanger]

I disconnected both of the fluid cooler lines - no pressure, just a gravity trickle. I am assuming this result removes any need to perform pressure checks at any of the test ports? Is the next step to remove the tranny for further inspection?

 

[Transman304]

No further testing required. Remove trans. More than likely a broken pump. Get it out and if you want to take a look at it i can walk you through it. Let me know.

 

[ColoradoRanger]

While I have this tranny out this weekend,(assuming I find a bad pump right away) is there anything else I should do while it's out? It doesn't leak and has had zero shifting or other issues up until this pump problem. Again assuming it's a pump only problem - don't fix what's not broken? Or is there work that you REALLY "have" to do if you have the unit out anyway. Thanks.

 

[adsm08]

If you replace the pump you should replace the converter as well.

An easier, less mess, and more accurate test of pump action in an auto trans is to mark the fluid level (assuming it has a dipstick) with the engine off, and then start the engine and check the fluid level again. If the pump is working at all starting the engine will produce a significant drop in the level of the fluid shown on the dipstick.

While opening a cooler line should work fine on a 5R55E, on many more modern transmissions the cooler lines are blocked by a thermostat and won't flow without the trans at temp, and sometimes even in gear.

 

[RonD]

And just as a general heads up.

You need to install the torque converter on the trans and then rotate it while push in on it.
You will feel, and maybe hear, it click in and slide in a bit more, it should do this 2 or 3 times.
That is the torque converter locking into the front(main) pump gears/splines.

Many years ago on my first auto trans replacement I didn't know about this and so FUBARed my front pump, which I didn't find out about until I tried to put it in gear, lol, so after complete reassembly.

The test is that the trans bell housing should slide on flush to block, torque converter should NOT be in the way of a flush fit.
After bell housing is bolted in place torque converter will slide forward slightly to be bolted to flexplate

 

[ColoradoRanger]

OK...finally got the transmission uninstalled this weekend from the XLT with no forward or reverse. Fluid was in really good condition and no visible or magnetic particles in it. Before I go any farther on this thing I want to ask about my observations so far: The transmission input shaft (outter shaft) turns by hand smoothly turning the output shaft as it should when in gear. The inner shaft will not budge by hand. It slides out and the splines are all in visibly good condition. There is no play in the shaft rotationally. Should I be able to turn this shaft? Is my next step to delivery this to a specialist or to press on with some more troubleshooting? Thanks guys!

 

[Transman304]

The way you are explaining the movement is totally opposite of what it should be. The "outer shaft" is part of the stator and should NOT rotate.

 

[ColoradoRanger]

I've been edumacated....this site http://www.lerouxbrothers.com/Trannies101.html was tremendous for throwing some knowledge at a slush box ignoramous like me. So....the outside shaft is the stator shaft and should NOT turn, it's function is to anchor the entire convertor and stator. the inside shaft is the input shaft turned by the turbine in the converter, supplying power to the tranny. So with that being said, and the fact that the input shaft does what it's supposed to (when manually turned) does that mean the problem is most likely in the torque converter itself?

 

[ColoradoRanger]

Thanks Brad for the quick reply. You happened to reply while I was typing an updated entry after doing more research. Yes, the input shaft turns and provides movement to the output shaft thru the trans when manually turned.

 

[Transman304]

Not going to be converter. it will be pump problem. Look down in pump past front seal and you will see the inner gear which had two flats to correspond to the flats on converter hub. Take a slim screwdriver and reach in and see if you can move the gear. What does the converter hub look like, have any rough areas around the flats?

 

[ColoradoRanger]

OK, removed the bell housing and the pump. Got lucky, broken tooth jammed so tighte was no grinding. Also explains why the engine stopped when it broke. Only other wear or damage visible is the main brass bushing in the bell housing.
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