I have a 97 f-150 with the 4.6 and the 470w tranny. My truck has been having problems for the last 3 months. A intermittin missing problem and a real bad jerking problem right before it downshifts. Finally my engine light came on and i had a friend read it. I cant remember the code but it said it was the Transmission control switch. Does anyone have any info on this? Any help will be really appreciated Thanx.

 

The exact code would be very helpful here. The only reference to a "transmission control switch" in regards to the 4R70W, is the O/D On/Off switch at the end of the shift lever. In instances of the switch failing though, it would simply keep you from locking out overdrive. There shouldn't be any drivabilty problems with this switch failing.

 

I believe it is P1780.
I got this errorcode.
There was nothing wrong with the switch it self but definitely there was something wrong with the transmission.
I have the 4R70W.

 

That switch is there for 2 reasons: To lock out O/D and to indicate a transmission sensor failure, by flashing.

SENSOR
Transmission control switch.

SYMPTOMS
No overdrive cancel when switch is cycled.

DTC
P1780

ACTUATOR
Transmission Control Indicator Lamp (TCIL).

SYMPTOMS:


- Failed ON - overdrive cancel mode always indicated, no flashing for EPC circuit shorted, or monitored sensor failure.
- Failed OFF - overdrive cancel mode never indicated, no flashing for EPC circuit shorted, or monitored sensor failure.

Is the O/D switch blinking? Does the light turn on by itself and the make the transmission downshift to 3rd gear suddenly?

 

my overdrive light is working fine. It shifts in and out of overdrive at the touch of a button, like its suppossed to. Heres what happened. For the last couple of months ive noticed that sometimes when i approach a hill my truck will jerk , kinda feels like im running over slight speed bumps. As time went on it got worse and worse. Finally I it started doing it on flat surfaces as well. But as soon as it changed into a lower gear the jerking would go away. The last two weeks its been really bad . And last week i was going up a hill and it started jerking really bad. The most ever. I just kept going at a steady pace and let it do its thing, i didnt let off the gas or give it more gas or anything . It got so harsh that my dash popped open . And at the moment that it was the worst my engine light came on . Then the next day i went to a friends house who just bought a 3200 dollar computer and had it read. And i believe it was code 1780. Any way it said transmission control switch.

 

The 1780 code will only set if you don't press the OD switch while the self test is running. The switch will not set a code while you are driving.

 

explain ?? what do you mean self test? My overdrive light never flashed. But my engine light came on while i was driving, its the first time my check engine light has ever came on , it set a code 1780.

 

Tennessee; I had the same problem a month ago with it jerking and kicking in and out of OD...solution; new wires and plugs

 

TN,

I had the same symptoms with my 98' f150. It would studder and jerk when at about 35 to 40 mph in overdrive. When I would apply more gas it would stop or if I let off the gas it would stop. I occasionally saw the O/D light flash and when that happened the transmission would shift extemely hard and adrupt. I took it into the stealership to read codes and check it out and they found excessive slip in the transmission and a bad torque converter. They said the fix was a new transmission and torque convert ($2200). I had 134,000 miles on that truck and never serviced the transmission (I know...not too smart). If you dont have high milage on your truck....changing the fluid in the transmission and the torque converter plus a new filter may help. The trasmission place said not to change the fluid if the transmission had over 80K and had never been serviced however...something to do with a varnish build up on the internal parts...said it would make things worse.

Good luck.

 

Self test is whem the scan tool is connected to the truck to retrieve the codes. You need to press the overdrive cancel switch during the engine running test or you will get a code P1780.

Quote:

My overdrive light never flashed. But my engine light came on while i was driving, its the first time my check engine light has ever came on , it set a code 1780.

No, it did not. The P1780 code won't set when the truck is running. It set because whoever cecked the codes didn't run the test properly.

 

TN Hillybilly,

It may be that your friend doesn't quite understand how to use his new scanner.

The transmission has sensors in there to pick up on any alteration in performance from the stock parameters. From my experience with the 4R70W, these sensors are actually very, very sensitive and will cause a flashing TCIL (Transmission Control Indicator Lamp) at the slightest problem. When something is wrong with the transmission, that light at the end of the lever will blink, rather than setting a MIL for check engine.

The problem you're experienceing sounds like an ignition issue to me... Like an intermittent misfire. To back that up, I've recently had similar problems with my truck. On occasion, I would start the engine and everything would be fine till I put it in gear. Then it would begin to shake and want to stall. If I turned it off and restarted, everything would be fine. I'd also feel a sudden, hard jerk from time to time on the highway. I was thinking that the problem was the torque conveter or TCC solenoid.

Today, I checked the spark plug wires and when I got to cylinder #1, the boot fell off the plug when I touched it. The issue with my truck was an intermittent misfire.

Many owners report that the 4.6 engine can go through coils fairly quickly. I'd suggest that you look at all of your coils and plugs. If you are missing on one cylinder as you drive down the road, you can certainly expect that your truck will shake violently.

 

tennessee,

im having the exact same problem as you with my truck and i mean the EXACT same. it does the same thing yours does. jerks like when going up a hill in od but will quit when it gears down or when you apply more gas. i changed all my plugs wires and it didnt help. what i did do was change my fluid which only had 5000 miles on it and it didnt do it for a couple days but now is doing it again. i think that its the torque converter but it doesnt do it enough for the service dept to actually diagnose. your systoms are exactly to a t what mine are. i think its internal as i did change the fluid and it helped for 2 days now its doing it again just not as bad yet. can anyone help us with this? as i said i changed everything and the only thing that phased it was the fluid changed which was done 5000 miles before. SOMEONE PLEASE HELP US i have 300 miles left on my warrant

 

Thanx for all the info guys. I failed to mention that i actually thought it was the plug wires for a while to. Ivw had them changed three times now though, within the last four months. The first time i put new plugs and wires i used magstar wires. Then the problem was still there, so i took it to a local shop. They said that i bought wires that wouyldnt work right , like maybe the boots werent going on the wires good. So i ordered the msd wire set. Still the same problem, so i took it to a different place. They told me the msd wires wouldnt work or the must be bad, they said they couldnt tell anything else until i put original equipment wires on it. So again i went and purchased the original motorcraft wires at 140 dollars and had the shop put those on . And still the same problem , it didnt change anything at all, so i decided the wires werent the problem . If anyone needs any wires i got 2 extra sets. ive also changed both the coils, and ive had the egr valve and dpfe sensor or whatever its calle replaced. non of my plugs look like theyve been misfiring when i checked them. ive had the fuel pressure checked and the injectors checked and cleaned out as well. ive got around 800 dollars spent in finding this problem already, I just hope i can get it fixed long enought to trade it in. I appreciate all the information guys . Im always open for ideas . A couple of different people told me that it was my torque converter . I am supposed to take it to a shop in a nearby town next week . The problems gotten so bad now that i cant even drive my truck in overdrive , as soon as i push the button it starts jerking like crazy.

 

tn, please keep us updated as mine is doing the same thing

 

I have the same crappy problem as the other guys. My trans has about 130k on it. The previous owner didn't service the trans so I did. Brought it to a shop for a trannie power flush. Didn't help. Love the truck but the trans problem is driving me nuts.

Mike aka Pastaman