My 1995 F-150 has a 351w and a 4x4 E4OD trans. 204,000 miles.

It has been suffering from rough shifting 1-2 and 2-3. It seems to shift at the right points, but it knocks my head back when it happens. Often I can hear "Clunk" when it happens. Shifts seem less rough when I am really getting on the throttle--they are the worst when the engine is fully warmed up and I am driving normal-light.

Also, when the truck is warm, putting the truck in drive from park, or reverse from park, or drive to reverse, or vise versa, There is often a loud clunk, and a lurch as the gear engages.

I at first suspected speed sensor or other electrical problem, but the speedo and cruise control are working completely normally. I still thought that perhaps something electrical had happened that put the truck in "Limp Mode," but when I check the codes I did not find any electrical, or speed sensor related codes... What I did find was a stored 628 code: Clutch slippage. I pulled the negative battery terminal for a bit, and after reconnecting it, I drove about 20 miles. There was still plenty of lurching and clunking upon shifting. Then I did a running code check and found only current 111 codes, and a stored 628 code.

Today I took the truck out to a flat highway, got it up to 60 and simultaneously pressed the break and the gas pedal, maintaining 60mph. The RPM and tach rose a bit. After I had the truck completely warmed up, I tried it again: the engine revved a bit but not as much as the first test. I think this confirms a failing, or at least wearing TC, right?

So here is my question(s):

I think it is safe to say that the TC is probably going bad, but is it necessarily causing the rough shifting? Could it be that the tranny is going bad too, and that I should replace them together? Or is the tranny likely still good, and I need to replace the TC asap to prevent it from sending broken turbine bits through my tranny?

I figure I can buy a remanufactured TC for ~$99, but I also have a line on a newly remanufactured transmission, transfer case, and torque converter combo for $1,500. Since I will have to drop the transfer case and transmission to get to the torque converter anyway, I want to know if I ought to just do them all at once?

 

Were you at exactly the same speed, and did you press the go pedal exactly the same amount? You need to be looking at the electrical output of the sensor to know if you pressed the pedal exactly the same amount. If you can't answer yes to these questions all it confirms is that the converter is unlocking as it should.

A code 628 will cause rough shifting. Most likely your converter is bad. I say this because E4OD converters of that vintage were prone to cracks in the torque converter clutch apply piston. This leaks pressure and allows a little bit of converter slip. The PCM can detect this slip, and when it does you get a code 628.

There are no turbine bits that are going to go through your transmission. I have NEVER seen the turbine blades come apart into little bits. I've seen them dislodge, distort, and just plain fail, but never have I seen them turn into little bits.

You also are unlikely to have failing turbine blades at all.

I recommend replacing the converter and the trans together. At the mileage you have the trans doesn't have a lot of miles left in it.

 

Thanks Mark!

I took the truck to a local transmission guy. He test drove and checked the codes and said the truck is in limp mode. He saw the 628 code and told to me that the 628 code typically only appears when the transmission is in limp mode, and that TC slip is commonly detected in limp mode whether the TC is actually bad or not. He believes that the truck was put into limp mode by something else, likely the PCM detected some deviance in what it considered normal engine to wheel speed ratios. He said if the truck is in limp mode, clearing the codes will temporarily remove the extreme hard shifting.

He suggested that I clear the codes and drive the truck with the OD off on a highway for at least 3 miles. He said rolling for some distance in 3rd gear will retrain the computer on the math between the engine speed and wheel speed.

So he cleared the codes for me, and I turned the OD off for a 4 mile trip back to my office. Clearing the codes resulted in the shifting becoming completely buttery smooth. The transmission remained smooth for the entire short drive.

Is this transmission guy right about limp mode? Could my TC actually be ok? Despite there being no speed sensor type codes, could that still be the issue that put my truck into limp mode?

 

He's making up most of that as he goes along.

Code 628 is set when the PCM reads an RPM difference between engine speed and vehicle speed. It can only do this calculation in fourth gear with the torque converter locked. If it detects slip it can't tell WHERE the slip is, just that the engine RPM is too high. It then sets 628 and puts the trans in limp mode.

The calculation he is talking about takes much less than 3 miles. It will usually calculate this in the first mile, in any gear. Turning off overdrive will only prevent setting the slip code because it can only detect slip in fourth gear. No fourth gear, no code.

The only other possibility I can think of is a bad alternator. If you have a bad diode in the alternator that can put an AC component in the vehicle electrical system. The PCM can read this as RPM, and you get false speed readings on various sensors. I suppose it's possible this could set a slip code, but I've never seen that happen. I have seen error codes for sensors caused by a bad alternator. So that's possible, but your more likely to win the Powerball than have this happen.

If your torque converter is OK, then you have a slipping clutch in the transmission. Now you need to rebuild the trans and replace the torque converter. I don't think he's right, I think the problem is the torque converter. If I'm right I think you should rebuild the trans and replace the torque converter. So in the end it doesn't matter who's right.

 

I just drove home from work (about 20 miles). About halfway, the rough shift came back, and after I pulled into the driveway, I checked the codes. guess which code came on? 628.

I think you're right. Two questions:

Is driving the truck in limp mode harming anything but the transmission (and my neck)?

How difficult is replacing a transmission for a mechanically inclined person, who has a full set of shop tools, but who has not ever replaced a transmission?

 

One other question... Is there any way to disable the limp mode? If the limp mode is only there to preserve the transmission, and my solution is simply to replace the transmission and TC, I would at least like it if the truck could shift reasonably until I get a new tranny, no matter what harm driving out of limp mode inflicts on the condemned tranny. I'm not worried about gettin stranded either. I only drive the truck locally and I have family all over the county.

 

I had the exact same issues. Same code, limp mode,etc..

I decided I was going to replace the converter. While I was doing that someone else on here suggested checking the solonoid connector. The wiring was all frayed, and coated in grease/gunk. I replaced the connector while I had the Trans out.

I also put a transgo kit in while it was out.

Anyways, my issue has been taken care of. It's been a few thousand miles and it works great.

Check that connector first. This was mine:


Edit: I could keep mine from going into limp mode by keeping it out of overdrive on hills. It'd pull them in 3rd without setting the slippage code, but would reset it every time in OD.

Edit2: I made the decision to try just the converter due to a few things. One, my fluid was clean, just burnt. 2, there was no material in the pan when I dropped it. 3, when it wasn't in limp mode it worked perfect..

I bought a Trans jack from harbor freight and it made the job simple. It took 10 minutes to put the Trans back in the truck. I should have bought one years ago. The hard part is going to be if your exhaust is all rusted up. All of my parts simply came apart. No fighting, nothing broke. CA truck FTW.

Edit3:
https://www.ford-trucks.com/forums/1...-question.html

https://www.ford-trucks.com/forums/1...s-harness.html

 

There are two ways. First, you could write custom software that removes limp mode. Or second, you could keep overdrive turned off. As I explained above code 628 can only set in overdrive. If you don't run in overdrive it can't set that code.

 

I believe my TC locks in 3rd if I have the OD button keeping it from shifting into 4rth. As 3rd is the 1:1 gear, it would seem this would be the easiest condition to make the TC slipping calculation? But in 4rth is likely the gear the trans spends most of its time in, especially under a load.

Interesting read...

 

I think I'm going to take the route of replacing the tranny. I'm more worried about the time it will take to take the transmission down and reinstall it over and over again to figure out the issue than the cost of a new unit. Also, it does have 204,000 miles on it.

Another question, I know my transmission is a e40d, which I understand is less efficient than other light truck transmissions, but is necessary for heavy pulling. I don't do any heavy pulling, just a bit of junk in the bed, commuting, and a bit of offroading for weekend hunting trips. So my question is, is there another transmission that will directly fit, that is more suited for fuel economy and drivability?

 

After price shopping, I ended up buying an already complete bench job with a shift kit+a remanufactured torque converter for $850. It came with a 1 year warranty.

So I dropped the old transmission, and installed the new one, but I have two concerns:

1. I believe I got the torque converter all the way on (this one has 4 studs welded on the outside of the torque converter, and after what seemed like 4 thunks in, I got the tips of the studs well into the bell housing. However, when I mounted the transmission, the studs had to poke 1/3rd of the way through the holes on the flex plate for the bell housing bolts to be able to go all the way in. when I put the nuts on the 4 torque converter studs, tightening the nuts pulled the torque converter body forward about 1/4 an inch to meet the flex plate. It seemed about right, since without the studs, the tc would have been able to spin freely, but I remember hearing somewhere that I should have been able to turn the tc freely with the transmission fully mounted... Or does that only apply to tc's with threaded holes instead of protruding studs? Anyway. I'm just looking for peace of mind before I fill it and fire it up.

2. The transmission I bought was so cheap because it was originally built for someone else's 1994 Bronco 5.8, and the customer never picked it up, so after a few months the shop was trying to get rid of it. It fits just right with one exception, the electrical connectors are just a bit different between the 94 and 95 solenoid packs. For the shift linkage sensor connector, I simply used the shift sensor from the original transmission in my truck, but the solenoid pack connector is another story. Right now I'm leaning toward just splicing a 94 style solenoid pack connector to my truck's wire harness, so it will fit the 94 style solenoid pack in the new transmission. The post pattern is the same, so I figure it won't be an issue. However, I wanted to ask, is there any reason why I should instead swap out the entire solenoid pack for one that has a 95 style plug?

 

1), the point that was supposed to be made is that the torque converter shouldn't be tight against the flex plate, after bolting up the transmission. You should be able to spin the converter back and forth within the confines of the holes in the flex plate. Not that the converter should be able to spin freely and not touch the flex plate.

However 1/4" back sounds excessive. I've never had one with that much clearance. I'm honestly not sure if that's a problem or not.

2)No idea, but a little searching on here can find the answers. I've seen it before.

 

Err... I would wait for a definite answer on that. If the connector changed then it ain't too hard to imagine that the components connected thru it also changed.

 

Sounds the transmission guy you talked to was pretty smart. There are different limp modes for different vehicles and different situations. In your case I suspect limp mode was triggered by the PCM detecting torque converter clutch slip. The band-aid strategy for that is the PCM commanding maximum line pressure. Hence the banging shifts and engagements. Commanding maximum pressure is a standard limp strategy in a lot of transmissions.
I'm willing to bet a new converter wouldn't have help much or for long. There are valves involved with controlling converter lockup which are prone to wear issues.
There are connector kits to allow you to use a later model solenoid block in an earlier truck but I don't think there are ones to go the other way. I don't know that for a fact though. If it were me I think I'd either swap in my old solenoid block or snag a wiring pigtail from an earlier truck. Either way should work. If you change plugs, go by the wire position in the plugs, not the colors. I'm thinking the colors changed around some between years. For no good reason at all.

 

I know this is an old thread, but I thought it would be best if I left a resolution (I hate it when threads end with out the solution/resolution!)

I ended up just putting in a 95+ style solenoid pack. I'm glad I did, because I could see that the diodes were quite a bit different between the two packs when you looked at them side-by-side!

After I put in the new solenoid pack and buttoned it up, I filled the tranny up (8, 12, 16, top-off method) and started driving. I stopped after 20 minutes to recheck the fluid level and check codes. Only code was 111-all clear! The bench job drives wonderfully, with one exception: the tech that rebuilt it put a transgo shift kit in it, so the shifts are a tiny bit firmer than I would have liked under heavy accelleration. But that's to be expected, and is fine with me. I have drived nearling 2,000 miles since the swap. Still driving great, and no codes.