Since you are the resident tranny guru can I pick your brain?

I have intrermittent problems with my 96 E-150 4.9 Quigley 4X4,
It has an E4OD (2wd version with adapor for transfer case) The truck has 212,000 miles but has had a Ford reman tranny installed at one time, I only know this because of the sticker. Now to the problem...

Please note I NEVER had a problem until... I serviced the trans (pan oil and filter only, no converter drain) Everthing in the pan looked normal, fluid was a little dark but no residue in the pan. I apparently underfilled the trans by 1.5 quarts I drove the truck 350 miles to my cabin towing my ATV on a small trailer with no problems. Whikle I was there running around the oD light started flashing and the trans started shifting hard, I pulled over and tuned the key off then restarted and no more problem. I drove the truck up there a few more days before returning home and all the way home (350 miles) with no other problem. The day after I get home I am driving and the trans starts shifting hard and seems to go into neutral at 50 MPH then slams into gear.
This is when I find that I am short 1.5 qts on fluid.

I add the fluid and the trans seems good for a few days. It then starts slamming into gear with the OD light blinking again. We scan the PCM and discover a code for the selector switch, upon investigation I discover that someone left the seal off the harness connector at the selector switch and the connector is all corroded. I replace the swtich and clean the harness terminals I also install a new seal at the connection.

All is fine for a few days then I start getting intermittent OD light flashing and hard shifting. It may go days or a week with no problem then have the problem once a day for a day or two then normal again. We have scanned for codes with nothing in the memory. I have been trying to get to the scanner whaile the light is flashing but buy time I get there it goes off and shifts normal again.

Sorry for the ramble, I tried to convey the problem as accurately as possible.

Do you think I did internal damage to the trans by running it low on fluid for 700- 1000 miles or is this just a coincidence and a control systems (computer) problem?

Thanks in advance for any help you may be able to offer.

 

I would think that if mechanical damage had been done, you'd have a constant problem, not intermittent. Only idea I can offer is to disconnect the battery for 15 minutes or so to reset the computer and see what happens. Let us know how it goes, and good luck!

 

Heat kills electronics. There are shift solenoids that may have gotten too hot. I'd check your fluid level again. It may be time for a flush. and a complete fluid change as the fluid dissipates the heat.

 

Sorry it took me a few days to get back to you. I was out of town all last week as the SCCA National Championships.

It is quite possible that you may have done some damage. Fluid level is critical and 1.5 quarts is a lot. Towing 750+ miles 1.5 quarts low and I would fear you are more than likely to have done some damage. That it didn't have a slip code, either a torque converter slip code or a gear ratio error (which is an individual gear slip code) is a good sign that you may be OK. However, I think this may be a different issue from the symptoms you are describing.

What you are describing I don't think of as a problem that would result from running it low on fluid. The MLP (manual lever position sensor) code would have nothing to do with the fluid level. The MLPs are a source of a lot of odd problems on Ford transmissions (Heck, I had a bad MLP on my Taurus that caused the radio not to play! Yeah, I know that's REALLY stupid, but there is a reason for it.) so this is probably just coincidence.

When you replaced the MLP and cleaned the connector, did you adjust the new one as per the service manual's instructions? Some of those have a hole that you stick a pin through to align it with the case. If not, I use the scanner in data mode to align the MLP in neutral and then verify all of the other positions (Park through manual Low). Its possible that the MLP is right on the edge of being out of adjustment and it might sometimes be reading wrong when you think the shifter is in Drive. This could set a "soft" code which may not remain in memory. The PCM may have to see the problem multiple times in a single key cycle or multiple key cycles to set a "hard" code and store it in memory and its just not getting there yet.

Another possibility is the connector could still have a high resistance connection that is causing an intermittant voltage drop which would give a false reading to the PCM and cause a soft code. If its not an adjustment issue I would replace the MLP connector. Then too, just because the MLP is new doesn't mean its good. I have seen brand new electronic components be bad right out of the box. I would be sure to eliminate the MLP, its adjustment and its connector before going any further.

I know you said that you didn't have any problem until you changed the fluid but I really don't think they are related. The coincidence is actually quite common. The most common time to service a transmission is before an long trip or heavy use (like towing) because people get worried and think that its a good idea. It actually is but then you drive the vehicle for long distances under heavy load and that itself is likely to cause any potential problem to surface. The trigger was the long hard drive, not changing the fluid.

Any more questions, let me know. Hope this helps and hopefully, this is the problem and its an easy fix.

Steve
'95 Clubwagon XLT

 

Thanks for the replies guys.

Clubwagon,
The MLP reads correct gear positions according to the Scanners. I've had both the old Snap=On scanner and a MODIS on the van several times.
Since my last post I did come up with a VSS code and changed it, for $16.00 I figured change it. It's not worth the diagnostic to check it.
The problem still persists. VSS code came back and sometimes I can feel a strange downshift immediatelt followed by hard upshifting that will disappear and normal shifting resumes almost immediately. Only once since the selector switch change have I experienced the problem of seemingly being in neutural for a second then slamming in gear. The past few days the tranny has performed just about flawlessly... makes no sense.
When I was in the biz I used to be pretty good at these imtermittent problems but since I've been out of the loop (Haven't wrenched for a living since '95) I haven't kept up on things and I'm more than a little rusty.

I have begun following wires and disconnecting/cleaning harness plugs just to be sure someone didn't leave a seal out of a connection somewhere and the wire got corroded. BTW I should mention this is a Quigley 4X4 conversion, do you know/think if maybe they tapped into the harness somewhere? I was told at one time that a 4X4 truck has a connection to tghe computer to change the shift program for 4X4 low range?

 

Can't imagine that there would be a different shift stratedgy for low range. The only thing I can think of is TCC operation.

What was the VSS code? I have seen plenty of VSS and MLP problems that were wiring issues. Did you ohm out the harness?

Steve
'95 Clubwagon XLT

 

Actually, I think it would have one... In low range, the computer would need to shift differently to keep the engine in the peak torque range. Low range is usually used for towing large items, or pulling a severly stuck vehicle out.

 

The transmission shifts based on vehicle speed. When in low range there is a 2.7:1 ratio in the transfer case, so if the shift strategy isn't changed the truck won't go fast enough to upshift.

For example if the 1-2 shift normally happened at 20 MPH you would have to go 54 MPH when in low range to make the 1-2 shift. That's not going to happen!

 

Yes, but only if the VSS in mounted in the diff housing. Most of the Quigly 4x4s have them mounted in the extension housing in front of the transfer case so the VSS never sees the change in transfer case gear ratio.

Steve
'95 Clubwagon XLT

 

Mine is in the differental... Or maybe there is another???

Clubwagon,
The code is VSS circuit and no I have not ohmed the harness, the only wiring diagrams I have at the moment are on Shopkey and they are a pain to read. If I get a chance to print them they will be easier to read on a 'puter screen they suck. I'll do that at the next operatunity.
Oh, By the way... Two straight days with not even a hint of a problem.

 

If you have a VSS in the Diff, then there won't be one on the transmission. There may be a hole in the extension housing just ahead of the transfer case where one _could_ be mounted but there won't be two.

VSS circuit codes are pretty common and typically mean the sensor is good and you have a problem somewhere else. This can be the harness or sometimes the PSOM or its connectors. The PSOM (Programmable Speedometer/Odometer Module) is mounted on the back of the speedometer. The VSS signal goes from the sender to the PSOM and then to the PCM. I have seen the PSOMs go bad and cause intermittent VSS issues. This is often a heat related problem.

You said its been a few days with no trouble, is the weather cooler now?

Steve
'95 Clubwagon XLT

 

No, weather is about the same. I didn't think there would be two speed sensors. I'll check the harness connectors if the problem sufaces again. I know it will... just a matter of time. The PSOM is directly on the back of the speedo head? I see the wire (pigtail) that is used to reprogram it I can just follow it.

 

Yes, but you will have to pull the instrument cluster to see it.

Steve
'95 Clubwagon XLT

 

Thanks


BTW Another day... no problem. The tranny is probably getting ready to grenade.