My 2000 F150 S-Cab (5.4L) has been exhibiting harsh upshifts during moderate to hard acceleration. Additionally, it has harsh downshifts when dropping out of overdrive and into the lower drives.

The transmission fluid (t/c as well) and filter was changed about 20K miles ago. I also noticed the 40 and 60 mph shimmy is back when coasting.

Trans fluid is still red and does not have a burned smell.

Any suggestions would be appreciated.

Jeff

 

BTW, I'm not a Certified Ford mechanic.

My guess is the electronic pressure control (EPC) solenoid is either faulty or some condition is causing the EEC to send a signal to the EPC to raise line pressure.

There are several sensors that communicate with the EEC so it can determine the proper signal to send to the EPC. If any one of the sensors sends bad info to the EEC, then the EEC could in turn compute a bad EPC signal to go to the tranny. Or, the sensors are reporting exactly what is really going on and the EEC is responding as programmed, ie normal.

I've had a similar experience with my truck and several weeks ago I installed a Transgo shift kit and now, after a recent 500 mile trip, my tranny is starting to shift hard too. I've attributed it to not actually getting the transmission up to normal operating temps for almost two weeks, I only work 3 mins from home. I drove up into a slightly higher elevation which affects several sensors sending info to the EEC and this may have attributed to the harsh shifts too, but I would like to think not.

Here's a short list of sensors that provide info for the EEC so that it can determine what signal the EPC has sent to it:

1. Mass Air Flow (MAF) Sensor
2. Intake Air Temperature (IAT) Sensor
3. Throttle Position (TP) Sensor, Mostly called the TPS
4. Output Shaft Speed (OSS) Sensor
5. Transmission Operating Temperature (TOT) Sensor
6. A/C clutch cycling pressure switch

In addition to any of these sensors either going bad or providing bad info to the EEC, the EPC solenoid could be faulty or something else within the EEC is causing the problem. All the things I've mentioned are electronic, there are other things withing the transmission itself that could cause harsh shifts but my bet is on the electronics. Also, some external condition causing one of the sensors to report outside weather conditions to the EEC is just performing it's intended function.

My 2 cents.

~DM~

 

Great News! I took my truck to a Ford service dept. last week. They "power flushed" the transmission and converter and added a conditioner to eliminate vibration. Additionally, they performed an flash update on the PCM for the harsh shifting.

So far, no vibration at 40 mph and no harsh, bucking shifts.

 

Well, the harsh 1st to 2nd and OD upshifts are back! I do not have the vibration that was exhibited before, but these harsh shifts have got to go. I will take back to the dealership that performed the flush a couple of months ago.

Jeff

 

Which transmission do you have, a 4R100 or 4R70W. The door code will tell you, E is 4R100, U is 4R70W

G

 

I have the 4R70W. Anything I can suggest to the dealership?

 

Factory Tech. . . Any suggestions on the 4R70W concerns?

Thanks, Jeff

 

I have similar problems.Tranny was flushed.
What exactely is a flash update on the PCM??

TIA

Waiting for a new tranny housing and bushing.
39,000 km

 

That is where new software is installed in the Powertrain Control Module (PCM.)

 

Hi Jeff
I guess i have the same problem as you with the bucking tranny. I posted the same problem before I read yours. I am going to another dealer today and see if they can come up with anything that might work like the Flash update. I will try anything before paying for remanufactured Tranny. Mine is out of warranty by years, not miles. I think the tranny is defective and should be replaced by Ford, but good luck doing that. I was told of something called a PO5 which allows Ford to replace parts like this that are out of warranty. I don't know anymore about it but it's something to check into. If you come up with anything that works, please post it.

1999 Ford F150 Lariat Stepside 4X4 5.4 engine

Thanks John

 

Thanks for the replies...I'll keep you posted.

Jeff

 

Regarding the harsh shifting, it has gotten worse. When I accelerate moderately to fast, the transmission shifts hard through 2nd and 3rd. When I am coasting at 55 to 60, then "punch into it", the transmission exhibits a 1 second delay and then abruptly down shifts. Secondly when slowing to around 20 to 25, then try to accelerate, it boggs down until I give it a slight bit more gas, then it abruptly down shifts and throws me back in my seat.

Friday, May 9, it is going to an independent transmission shop for diagnosis before my 75,000 mile ext. warranty expires.

I'll keep you all posted. I hope others have had their similar problems with the 4r70w fixed. Keep me posted as well.

Jeff

 

Transmission and TC in my 4R70W was drained and filter replaced. The independent tranny shop near my home stated that ford and chrysler dealers frequently send him their problem childs. What the mechanic indicated is that eventhough Ford states to add Mercon V he adds Dextron III.

So far I am very pleased with the results. I do not have the abrupt shifts nor do I have the nagging lag before shifting or shuddering. I'll keep you posted.

Jeff

 

OE812 it's a week later is the trans still performing right after the fluid change?
When was the previous change?
I am struggling with this harsh shift issue as well. I, from reading this and other posts was leaning toward replacing the EPC solenoid. If a flush might help I'll try it first. My last flush was about 25,0000 ago and filter was not changed. Fluid still looks and smells "Good".
BTW could anyone tell me how difficult an EPC change would be and what's required.

 

I would not recommend the flush. Have the filter and fluid changed in the TC and pan. The independent tranny shop does not perform flushes because they claim that contaminants will remain in the filter after a flush.

So far, the transmission is operating fine. It shifts much better without the abrupt shifting it exhibited before the trans service.

I'm not certain if the Ford Mechanics would agree, but the indep. trans. shop filled the pan with Dextron III; not Mercon V as stated on the dip stick and owners manual. He did this knowingly and without regrets.

I can not recommend this but this is what I have in the pan and so far...so good. I'll keep you posted.

Jeff