yet another E4od issue...trans shop stumped!

[DavidS]

Hey guys, I finally got the rebuilt motor into the truck and drove it for the first time! A fresh motor and a turbo make for a noticeable difference over the '88 NA! Thanks for everyone who helped me as I was getting through that project!

So....now I'm having trans issues, and haven't even gotten through break-in

Here's the breakdown:
Minor issue: 1-2 shift bangs when cold, then smooths out
Major issue: After the truck is good and warm, getting back into the accelerator after coasting at around town speeds (say after slowing slightly for the car ahead to make a turn) reaults in the engine free spooling in neutral, before slamming down into gear. Once it has done this once it does it every time until the truck is off and cooled down. The first time it happened a group of codes were thrown: VSS insufficient signal, FIPL sensor out of range, and an MPLS one I can't remember.

What's been done:
I replaced VSS. Removed part had very minor dusting of metal. Replaced with NAPA unit. Cleaned connector. No difference after test drive and VSS code returned.
Shop replaced MPLS with OEM unit. Same shop adjusted FIPL to provide correct readings. Those two codes did not return after test drive but shifts were now occuring way to late, so they adjusted the FIPL again and got shift points to return to "normal". I don't believe that code has returned yet. It doesn't make sense to my brain that the correct adjustment per volt meter would not yield correct shift points...

The last item the shop noticed is that when measuring the reference voltage at the FIPL which they said should be a steady 5v, they observed it fluctuating, but they can't determine the cause.

So now they arean't sure what to do next. Before I take it to another trans shop I thought I would see what you guys think.

Thanks as always!

 

[laserjock]

I’m no expert but that sounds like an internal issue not external electrical but that’s my very uneducated thoughts.

 

[trackspeeder]

Try another TPS. There should be no fluctuations what so ever. Any fluctuations will give a false signal to the TCM causing erratic shifts.

 

[gandalf]

You say the shop has set the FIPL at 5.0 volts? I see that as part of your problem. Their information is just plain wrong. It's getting harder and harder now to find a good shop which knows how to work on an IDI.

Read THIS article. It's in the Tech Articles which you will find at the beginning of this section of the forum, the section about 6.9 and 7.3 IDIs. Come to that, look through all the tech articles. There is a world of information there.

In actual fact it's almost impossible to set the upper figure, WOT number, for the FIPL. The way most of us do it is to set the idle number, and then check the WOT to be sure it is within range. Be aware that as the idle number increases your shift will become more harsh, more suitable for heavy loads. As the reading decreases the shift becomes softer. So, set it, tighten everything down, test it on the road, reset it more toward your liking, and so forth.

 

[david85]

When did this problem first start?

Based on what's been described so far, I have to second the internal issue.

Clutches and mechanical diodes don't usually cause problems like this, since oil viscosity drops as temperature goes up. I would expect slipping to get worse as the transmission warms up. The hard bang tells me that the load bearing parts of the transmission are still able to grab an hold torque. So the gears, clutches and mechanical diodes (sprags), are "probably" still working but the brains in the valve body are not. I've seen problems where heat would cause a spool valve to snag in the valve body as the transmission warmed up (not even overheat).

Having the engine go up to high RPM before the transmission grabs again sounds like a hydraulic snag somewhere in the valve body that eventually releases when enough RPM and line pressure are reached to force the valve. This allows the clutch to grab, with harsh results.

Now, it's possible that these symptoms could be brought on by an electrical fault too, but without digging deeper and verifying all the correct signals it's hard to be sure.

 

[DavidS]

@gandalf, just read the tech article you mentioned above, thanks for pointing me there. Definitely makes me want to go ahead and replace the FIPL. But aside from that the inconsistent voltage that the shop was seeing was on Wire A in the tech article, signal in to the FIPL, resulting in a garbage in garbage out scenario. The shop didn't want to start replacing things until they got that sorted out. Anyone have a schematic of where that voltage comes from and it's path?

@david85, the issues presented themselves almost immediately after the engine work was completed. Keep in mind I bought the truck not running, so I don't know know if they were present for the previous owner before the crank bearings ate themselves.

I guess what I'm trying to sort out is could the FIPL issue cause the trans to not engage a gear after coasting, or am I looking at two separate problems?

 

[Jefff27]

I had had a direct mirror to what is being described here. The solution was the connection to the solenoid packs on the passenger side. This would happen only when warm and not all the time and even sometimes when warm. Removed heat shield, cleaned connection with electrical cleaner and she shift like a dream again.

 

[Rick Dec]

I was going thru some of the same problems with trans shifting incorrectly. I ended up sending my dash out and be re done. All of my shift problems went away except lock up and cruise control. I ended up putting new brake bulb in stop light on back of cab. With those two things the truck shifts perfectly. If you lucky you may find a used dash in a junk yard for a diesel that would save you hundreds of dollors. Rick D. My truck is a 84 F350.

 

[DavidS]

Guys, I've been a ghost for a while, between a mostly DIY addition to our home, an infant somehow becoming a 2yo in the blink of an eye, and that corona thing, time just got away from me. Trying to jump back in a follow up on some threads that i had been part of.

While my trans is by far still not perfect, at least I have not had a trans error code/flashing OD light in a long time. After an instrument cluster rebuild the VSS code seemed to go away. Subsequently, the tach started dropping out occasionally which was fixed with a new tach sensor. This incidentally also smoothed out the shifting a bit. She still bangs some when cold, and the shop tells me a rebuild is not too far off for me but for now it's working. And as a side benefit all my cluster backlighting works!

 

[IDIBRONCO]

If your transmission seems pretty good other than the harder shifts when cold, I'd just drive it. It wouldn't hurt to be saving some money up for a rebuild just in case, but it may last you a long time yet.

 

[DavidS]

That's good to hear...certainly I want to do it right when the time comes so I will be saving up for sure. The only worry in my mind is the guys at my trans shop tell me don't wait until it completely fails, the rebuild will just cost more...Have to time it right I suppose.

 

[ISPKI]

Do you know what torque converter is in the transmission and what fluid they put in it? Also - what was the outcome of adjusting your FIPL?

 

[DavidS]

I do not know the answer to either unfortunately.

Back when the rebuilt engine was going back in, I had to make a call on the doing anything to the trans. The TC looked "newer" and the fluid looked good so I just put it back in since I was running low on funds.

The FIPL was adjusted until it seemed as good as it was going to get based on drivability rather than voltage. I did go ahead and replace it since I found a Ford one at a decent price. The replacement did seem to clean up some occasional hunting. To me the shift points are good when you're driving around town when it's just warmed up, but when everything is nice and hot i feel like it shift later than I would like and sometimes hangs for a second before it goes on to the next gear. No banged shift at that point, just late and slow (to me).

 

[ISPKI]

I gotcha. Are you able to feel the TQ lock? Where in the RPM range does it tend to shift at? There were several RPM ranges made for that TQ that will bolt right up and influence shift points. There is also a way to adjust line pressure to soften the shift engagement but I havent done that.

 

[DavidS]

Yes I can feel TC lockup. I think it occurs between 2 and 3. Unfortunately sometimes the TC lockup will go in and out at some around-town speeds so usually i drive with it off until I hit the highway.

When it's just warmed up, driving normally, it shifts around 2-2.5k. When things are hot i feel like it wants to wind out to 3k or better.