2006 F150 4x4. (4R75E) Recently acquired. Drove home 1.5 hours away just fine, at least as far as the transmission is concerned. Been working thru multiple issues and test drive after each fix. Most recently:
-only 1st and 2nd in D. When it shifts up to 3rd, engine just revs as nothing is engaged. Shifts just fine between 1 & 2
-Click off O/D and I get 3rd back with the press of a button. But never get 4th back. Shift from 1-3 is smooth as it should be.
-Runs fine in 1, 2, can shift to D at appropriate speed for 3rd from 2 but unless O/D is clicked off, still just revs.
-Doesn't try to move in neutral, so nothing grabbing that shouldn't.

New here but have found many answers on this forum for other issues the thing had when I got it, so hoping for the best. I've found really similar posts but no one ever mentions that 3rd works with O/D clicked off. So either no one has tried that, or this is completely different. I have no qualms about tearing anything apart, just really don't want to remove the tranny to find out it was something in the valve body or some sensor somewhere.

 

Likely this:

https://www.f150online.com/forums/tr...roke-pics.html

 

I was beginning to suspect that due to finding another video of a 4R70W having a similar issue and the snap ring broke off and jammed in front of a valve. What am I looking at here? Obviously pull the pan to get the valve body, but am I pulling the whole transmission for that solenoid? Is there something up inside of there it's attached to where I need access from another side or can I do everything from below?


EDIT: I just glanced at that thread earlier and didn't realize it was as detailed as it is. Sounds like it's all done from underneath, just keep track of what went where. so not bad. It's stupid hot out and this is a backup vehicle so it may be a bit before I get this fixed, but will report in when I do. The local shop is booked out for a month and a rebuilt tranny is about what I just paid for this truck, so... (it was, as a friend would say: Ridden hard and put up wet)

Cannot thank you enough for the quick response.

 

I've tried a lot of things. started with no reverse, overhauled unit and found broken reverse band. Replaced EPC solenoid and plastic wiring assembly . Back in truck, no 3rd or 4th. Turn OD off and now has 3rd gear. In drive with OD on and 1/2 throttle it will have 3rd gear but no over drive. Changed valve body and solenoids, same problem. Scanner showing to be applied each gear, input and out put sensors showing to be working, no fault codes, also reset the adapts. I would love to know what you found on your transmission. I started rebuilding transmissions in 1972 and I'm an older guy; this one has got me

 

This just took me a full day and an absurd amount of time to log in to this forum to respond to this. No idea why it needs to be THAT secure for something like this. Someone wants to hack my account, be my guest. That is to all say that I felt the need to respond because this issue kicked my *** for a LONG time. I replaced the entire valve body at one point.

When you lose 3rd and 4th but can get 3rd back with OD off there are 2 things that can cause it: there's an e-clip on a plunger in the valve body that engages the overdrive band that breaks. You need to clean out the valve body/fix that plunger OR: the overdrive band is shot. Valve body was easy. I pulled it 3 damn times. I found the busted e-clip and cleaned out the body, but that wasn't my only issue as it turned out. The overdrive band is also shot. And that requires pulling the whole transmission. So at that point I gave up. It's a 20 year old truck that I drove a total of 1,000 miles last year. It can burn a little gas. The thing was a guzzler brand new anyway.

There's a few videos I found of rebuilding/cleaning the valve body. I cleaned it twice thinking I hadn't found the issue the first time. Then I bought a refurbished one off ebay before I finally admitted it's the band. If you drive with a trailer a lot the band can go. I bought this as a beater from a guy who was clearly drunk every time he backed the truck directly into the trailer and dented the bumper, so I wasn't surprised the band went.

Good luck. It wasn't worth it to me. Really if you're going to get all the way in to the band, may as well just replace the transmission with a junkyard one at that point. At least that would be guaranteed to work. Hate to go to the work to replace the band and it still doesn't fix it 2 days later. I also had a transmission shop tell me that if the band blew then it destroyed something else and you can't just replace the band. I have a full machine shop at my disposal so I didn't care about that and he seemed fairly full of it, just trying to get $3k out of me for a full swap on a $2k truck.

I will say when you start messing with the valve body, make DAMN sure you have that OD band engaged on the piston before you close it back up or you'll be pissed.