Hopefully the title was descriptive enough to catch those who are willing to lend some help in the way of sharing their insight or experience. I hope that in the interest of being thorough I am not adding to the ambiguity of the problem.

The Truck is a 1994 F-150 4.9L6 RWD w/ E4OD Trans. Approx 190k. PO Passed away, truck was given to me and his family believes early on in their ownership of the truck the transmission was "repaired" (around 2001). The current transmission has likely not had a happy life as it's primary utility was towing. Fast forward to the current situation and the truck has set without being run in over three years. In the time it has taken me to update other components, fluids, filters, etc the transmission has failed me. The truck was lightly inspected by a mechanic for any obvious problems, transmission fluid was still red and was planned on being changed shortly on principle.

I let a family member borrow the truck to move some stuff from a storage unit and later that evening I encountered my first problems with the transmission.

I pulled into a parking lot and from a complete stop I attempted to changed into reverse to back into the parking spot. The transmission acted as if it wasn't in a gear. I don't know if you would describe this as slipping out of gear or returning to neutral. Anyway, the truck wouldn't move, and it didn't matter if I tried D or R and it didn't matter if I went to P before I tried to engage either gear. Nothing happened, no jerking, no grinding, no whining, it simply felt like I wasn't sending a signal to the transmission. I turned the ignition off and back on with the selector in P and the transmission promptly went into reverse (when the selector was moved to R) and forward (when the selector was moved to D) and didn't give me any more trouble for the remainder of the day. I thought it seemed like an electrical problem or perhaps a vacuum problem but I understand this is an electrical transmission. I thought perhaps it was ghosts in the machine as there was no corresponding noise and this wasn't occurring while in gear and traveling down the road.

The next day I started the truck up and the outside temperature was around 40 degrees. The truck ran fine and the transmission shifted through all gears giving me no indications of malfunction up to my initial destination (about 3 miles away). After departing from initial destination to secondary destination the transmission begin losing it's ability to motivate. This would happen between gear changes and when coming to a stop. Again I don't know if I should describe this as "slipping out of gear" or "returning to neutral." At any rate, the truck would no longer motivate forward, so as I had previous tried while in the parking lot, I turned the ignition off and back on again and then moved the gear selector to D from P at a complete stop and the transmission then would shift accordingly and I would move. This procedure happened around 4-5 times on a 5 mile round trip and after each time it was performed the transmission would seem a tad more testy. After returning home the transmission developed a loud whine. I would describe this sound as the sound of a power steering pump about to explode.

This was 4 days ago and in the days since I drove the truck I have done a series of light tests as the outside temperatures haven't permitted much tinkering.

At first I performed a KOEO Diagnostic test and pulled the trouble codes:

636 - Transmission Oil Temp Sensor Out of Range
452 - Vehicle Speed Sensor Problem
628 - Excessive Torque Converter Clutch Slippage

Unfortunately at this time I didn't make a distinction between active and continuous codes. Based on the way I wrote them, 636 and 452 were active and continuous, and 628 was active. At this point I began to search out threads with similar symptoms. This led me to a lot of threads on this website and on Full Sized Bronco dealing with E4OD diagnosis.

I learned that both the MLPS and VSS could cause mis-communication with transmission and ECU controlling transmission operations. Given my available working conditions I was not able at the time to remove any sensor, but I did inspect and clean connections and found that they were all dirty, moisture ridden and corroded. The MLPS's connector clip was broken, ajar, and covered in an icicle. This connector is of the pre-95 style and MLPS unit will be replaced. Also from what I read, poor communication with solenoid controller could be suspect. I read a thread on here about transmission fluid making it's way into the solenoid body electrical connector and causing electrical malfunction. Anyway, I wasn't able to get to this connector as it is eclipsed behind the exhaust, and the connector's release is facing the transmission hull.



With these connectors cleaned I performed another KOEO diagnostic test after unhooking the battery to clear the memory for the test.

In the active codes section I got a 111 or all systems check ok. In the continuous codes I received another 636 or oil temp sensor out of range.

At this point I performed a KOER test and got trouble codes:

116 - Engine Coolant Temperature Sensor Out of Range
129 - No MAP change during Goose Test
225 - Knock Sensor Not Tested

IMO all of these codes are erroneous at this time.

A further KOEO test was performed with trouble codes:

636 - Transmission Oil Temp Sensor Out of Range in Active Codes
111 - In continuous codes

After completing the KOER test, and the final KOEO test the truck sounded better. I let the truck run at idle for approx ten mins to bring truck up to operating temp for diagnostic tests. I was going to try and drive the truck but the persistent whining sound which only breifly went away while performing the KOER tests has kept me from driving, in addition to the fear of being stranded in this cold spell.

Even if the sensor mis-comunication ( if present) is accounted for with the cleaning of the connectors, I am worried about the loud whining sound, and as this was the title of my thread.

I contacted a mechanic who performed service to the vehicle just prior to these transmission problems, and in the PO care. I described to him the problem and he sounded intrigued until I described to him the whining sound. At this point he seemed confident this was not or no longer an electrical or sensor issue and told me that the transmission would likely fail and that he could refer me to a respectable shop. He did elaborate on what he believed the problem was, output shaft, or output shaft bearing failing and causing this whine. I know that he doesn't have a crooked angle on this as the shop he spoke about is highly regarded in my town and is the shop I have used previously.

My question is this, does it sound from what I have described that this could have been an electrical issue, but has now manifested into a mechanical issue sure to cause catastrophic failure?

Are there any other causes of a really loud whine other than bearings failing? Is there a possibility the lines to the cooler are clogged and the pump is running dry? Or perhaps the filter is clogged or something dealing with fluid/fluid pressure that might explain the whine? It's a really loud worrisome whine, but isn't a grind or clanking, just a loud whine, like a failing powersteering pump whine.

I even read a hypothesis dealing with a very similar situation in which the person posting stated "Great sign of the transfercase being bad. Reason being is that your brakes hold the driveshaft from spinning. The driveshaft is connected to the transfercase. The transfercase is not holding your output shaft at a stop so your getting the grind from the park prowl because the output shaft is still turning. So basically your transfercase is seeing neutral."

This whine is occurring while idling and in park. Also it may be of interest to note that the sound does not manifest immediately on start-up but usually after running in excess of 5 mins.

I honestly don't know if I should worry about sensors and trouble codes and replacing this sensor or pulling that component if this whine is indicative of some greater failure.

Is this something likely I will be able to fix without dropping the transmission (sensors/fluids/filters/solneoids/etc)? or should I start looking into inevitable repair scenarios (reman, rebuilt, junkyard, manual swap, scrap the truck, etc.)



Any overall information or consideration is appreciated, but questions I am asking are highlighted in red.


Thanks for any and all help.

--James

 

Well, if it's whining when you're stopped then it sure ain't the output shaft.
Gonna be either the torque converter or the pump making the noise.
What happens if you stand on the brakes and give it some gas? We're not trying to do a burnout/powerbrake here, just seeing what the noise does.

And yes, if you have fluid flow problems you could be starving the pump and cavitating it, which would likely cause it to make noise. Might drop the pan and check the filter, it's only held in there by the o-ring seal. Any time I have the pan off a new-to-me auto trans, I safety wire or otherwise secure the filter "just in case".

As for not going into gear, you have a 94... in 95 the MLPS connector (and MLPS itself?) were changed to an updated style which is less prone to water ingress. How's your MLPS look? I know you said you just cleaned the connector. Perhaps test the MLPS itself. I can't tell you how without seeing a schematic (am at work right now) but it can't be difficult at all if you have a multimeter.

Now I don't know for sure that a bad MLPS would cause you to lose reverse, as I don't *think* there are any solenoids involved with engaging reverse... I want to say this is purely a hydraulic function but I could be wrong.

Someone with more E4OD expertise will likely drop by with more precise answers for you.

 

If I can get it through my head that the whine can be solved, and isn't indicative of total catastrophic failure I will change sensors or at least check and clean current sensors and such.

 

Have you found a cure yet? I am currently experiencing similar troubles. Read my recent thread if you want to compare.