will not shift?

Okay, this sounds like either the valve body has sticking valves or there is a failure in the clutches inside the transmission itself.

https://www.2carpros.com/articles/automatic-transmission-problems

I would start by changing the fluid and filter and pay attention to the pan and see if there is any debris in the pan or on the magnet itself. If there is, there is a good chance there is an internal failure.

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

If there is not, good chance it is the valve body.

Please let me know if there are any codes set in the system.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Roy

4r70w stuck in second.

I was driving the truck down the road when it randomly got stuck in second. When I started from a stop it would not shift into first, I did not want to force it into first so I drove it home and parked it. When I scanned the computer, the codes were: P0750 shift solenoid A, P0755 shift solenoid B, P0743 torque converter clutch circuit electrical, and the overdrive light was flashing. I checked the fluid which was replaced at 100,000 by the last owner, and it was pink and full.

I've been searching desperately for answers as this is my daily driver, and I appreciate any help.

Thanks!
Conrad

Your description sounds like it is stuck in limp mode. That will make it operate in 2nd gear and not shift. The codes support that as they will cause limp mode. First thing you can try is to disconnect the battery and let it set for 5 minutes or so. Reconnect and see if it now shifts like it should. The cause is likely a bad connection at the transmission wiring connector, fairly common as the connector corrodes internally and the transmission doesn't know what to do. To check it is simple, go under the truck and unplug the connector and inspect it for corrosion or the harness for damage. If the connector is corroded spray some contact cleaner into both halves and plug it in out a couple times. Then apply a thin coat of dielectric grease and reconnect and see if you cured it.

Moves in and out of 1st gear then finally stays. Same with reverse Shifts fine once it stays in gear.

Good afternoon,

This sounds like you either have low fluid level or the filter is clogged.

https://www.2carpros.com/articles/automatic-transmission-problems

I would drop the pan and change the fluid and filter. In most cases, it is nothing more than a clogged filter.

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Roy

I put new filter and fluid in 35,000 miles ago. help

Does not matter at all.

I would drop the pan and change the fluid and filter.

Roy

Okay Roy,
I put new filter and fluid in.
Old fluid looked clean as did filter.
Didn’t take as long shift and stay in gear but keeps moving in and out of gear for first couple miles driving after that it locks in and shifts great.
Any ideas?
Thanks again.

Okay, then it sounds like the seals in the transmission. It could be the forward clutch piston seals. They may be hard and need time to soften up.

The transmission would have to be removed to gain access to these seals. It most likely will result in a rebuild or replacement of the transmission.

https://www.2carpros.com/articles/transmission-replacement-removal-manual


Roy

Oh man. Okay, thanks.

You are welcome.

Always glad to help.

Roy

When my engine is cold the shift from 2nd to 3rd is very rough and sometime my speed is as high as 40 mph before the shift. I have had my trans fluid sucked out but did not change the filter. I also have had 2 speed sensors installed at the local dealership. The longer my drive is the better the shifting gets. When I first drive in the morning the shift from 2nd to 3rd is very rough but smooths out after this. Any ideas before I go a transmission shop?

Sounds like a sticky valve/ shift solenoid or accumualtor.As it gets hot the fluid thins and all parts grow up (expand) and it works better.The will be able to scan the PCM and monitor pressures to see what it is.

Hey Roy,

I have a 2001 F150 Lariat 5.4 w/4wd .
Also have a 2002 same truck exactly.
Can i drop transmission and transfer case at same time using a trolley system for both with secure attachment for both transmission and transfer case on my jacks.
I have both totally exposed and ready to be removed.
Any info you have will be extremely appreciated.
Thanks Roy.

I can cut my cost for re-install by $400.00 if this is possible.

Yes, you can. I used to do it that way and I used 2 floor jacks to drop the unit all in one.

Roy

Thanks Roy.

Does transmission and transfer case use same fluid or are they different?
Thanks again.

Okay, I attached the fluid requirements for you below for both the transmission and the transfer case.

Let me know if you have any other questions.

Roy

Shifts from 1st to 2nd gears fine. When going into 3rd its like neutral end of any pulling period. Have 1st 2nd and reverse only. No 3rd and overdrive. Don't know about 4x4 portion of it have not tested it.
5.4 engine runs fine. When trouble appeared. On the way home driving 40 mph passed a car and hit passing gear not meaning to, but immediately afterwards it stopped pulling and I parked it and sat there until I got it towed 12 miles at 45 mph all wheels on ground in neutral. Blew front seal at some point leaked lots of fluid not sure when seal blew but was not leaking before this incident. I did slide trans back far enough to replace seal only bushing seemed okay somebody replaced it before I bought truck. Topped fluid off.
Thank you,
Bob

This sounds like an issue in the valve-body. The shift solenoid are inside the valve body that control each shift and a separate solenoid for overdrive.

I attached the process on how to replace this. I would suggest taking the valve body apart and inspecting it but the solenoids are only around $20.00 so I would just replace that and then put the valve body back together.

The solenoids control where the fluid pressure goes to determine what shift will happen. If the solenoid has failed it will not shift. However, your vehicle has one solenoid with two coils inside. So you would need to test each separately but with this being such a common unit, the components are pretty cheap so I would just go ahead and replace it.

Please reach out with questions. Thanks

From full stop acts one of two ways it'll either start slipping until I let up on the throttle or the clutch pack engages late and grabs hard. It's also acting up when maintain higher speeds. Especially around the 40 to 50 mph. It feels like it is jumping back and forth from what I'm assuming is third and fourth gears. People told me to replace the park neutral safety switch. It did seem to subside the issues for a couple drives but it came back. It may have been coincidence or it may be that I don't think the transmission fluid I don't think got to temperature. Could this be a solenoid? If anyone can help I'd greatly appreciate it.

Good afternoon,

the park/neutral switch has nothing to do with it at all.

https://www.2carpros.com/articles/automatic-transmission-problems

I would start by dropping the pan and checking the fluid and filter. If the filter is clogged, it will cause this. Look for any metal or dirt in the pan.

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Roy

Hello, I have a 2000 F-150 4x4 108,000 miles auto trans. I was headed to work yesterday and when I got on the highway I pushed the OD button. As I was going I noticed it didnt shift into OD I didn't think much about it until I went to pass a car it kicked into passing gear and wouldn't shift back into drive. Then when I stopped and took off again it wouldnt shift out of first. I moved the shifter to second and it shifted but wouldn't go into drive when I shifted it to D it stayed in second. When I stopped and put it in park the RPM's redlined and I shut it off. When I started it back up everything was fine on the way home it seemed as if the throttle wasn't quite as responsive as it was before. It seems to take a while to idle down and when I turn on the defrost the idle jumps up about 400 rpm then comes back down. I am thinking it is the TPS but that doesn't explain the tranny problem. I am a weekend grease monkey just need some place to start Thanks P.S no check engine light

Hi Brandonflores3,

Thank you for the donation.

Some trouble codes do not trigger the CEL immediately but is stored in the PCM. We should start off by trying to retrieve for trouble codes. Get a free scan done at Autozone and let me know the exact trouble code if any.

Problem is intermittent and could be due to a loose connection somewhere. If any trouble codes are found, it would assist in going through the diagnostics.

I will go and see what they say and let you know. Thanks again

Went to Autozone and had a scan I believe the code was p1201? It came up TPS not consistent with MAF. I put a TPS on it and imediately noticed a difference. Thanks for your advice I didn't know that the computer would show a code even if the CEL does not come on. I will definately use you guys again and have recomended you to 3 people already. Have a great day. Brandon

You are welcomed and thank you for the compliments.

Great to know you have fixed the problem.

Have a great day.

i finally bought a vehicle i decided on a listed above. what i'm wondering is it shifts. not really hard.. i can feel it shift from 1-2 or 2-3.. feels like it pulls quick it's hard to explain. smooth shift after that. i can feel a bump into gear. fluid is right up there where it's supposed to be. not burnt at all but i have no records. looks clean. thinking about changing the fluid. something to worry about? i think it's the 4R70W transmission. no check light or codes. i just don't like that shift.. i've been really babying it.

I have owned a number of these trucks and noticed they are a little firm. Based on what you are describing I would not be concerned. However, if there is something wrong it will get worse. Since you recently purchased the truck, I would give it some time and see if it gets worse. If it does then the pressure needs to be checked. If not, then this is normal.

Hopefully this helps. Thanks

thank you. i think i will get the fluid changed and keep an eye on it. thanks for the advice sir. it's been a couple months how long before it get worse if it does? i suppose it's hard to say..

It is hard to say but I would think you would have noticed a change by now. However, it could take months. The thing to remember is it will not just heal itself so if it is not changing then you are probably fine. Changing the fluid is a good idea but if it is full and in good condition, you may not need to do it. Again, it won't hurt so if it gives you peace of mind, go ahead and change it.

it's been awhile since i posted this, but the problem was a broken spring.

i posted last November about kind of hard shift from 1 to 2. it was an easy fix (accumulator spring). now i have noticed a late shift a few times. i'm going 55 down the road and suddenly i feel the truck shift. not down shift but seems to be going into gear at 55? how do these trucks shift? 4R70W

Good morning,

The shifts are electronically controlled. The main sensor is the throttle position sensor. It sends a signal to the ECM of the throttle position and the shift solenoids are turn on and off based on road speed as well.

https://www.2carpros.com/articles/automatic-transmission-problems

I attached a flow chart for shifting issues for you to view.

Are there any codes in the system?

How long since you changed the fluid and filter?

Roy