We have a 92 f350 7.3 4x4. 104k. Fluid full and clean. It was a cab/chassis if that matters when it was built. Flatbed now.

It starts flashing the OD light when it comes out of first w/ harsh shifts. FIPL has been replaced and currently 1.2 at idle and 4.0v at WOT. Speedo works. Vss ground cleaned. Vss Replaced. Tach works. Connector at solenoid pack checked and cleaned. All voltages seem to be present based off a post i saw with a similar issue. TCM/TECA connector checked and cleaned.

Odd thing is it will not display codes with either the OBD I code reader or using a test light. We have done it previously and it has always been very distinct about starting a clicking routine when it went into the test mode. It does not do that today. All fuses were checked as well.

I am leaning towards TECA bad but does anyone have another idea? This is a really super nice truck and this is the only glitch in it.

 

Sounds like a bad TECA. You can remove the computer from the truck and open the computer housing. Inside is the circuit board and some electrolytic capacitors. They have a habit of leaking after ~30 years. They're replaceable with a soldering iron.

 

Agree with bad computer. In my experience, replacing the caps doesnt help like it needs to be reprogrammed or something.

 

That is i was leaning towards but I knew some of you have a lot more experience with these. I was leaning towards a manual swap, but it works too good when it does work correctly. Ironically, on wet days, it usually works better than on dry days. It started doing it in the last couple months. We have not put many miles at all on it in the two years we have had it (7k) but even fewer since it started acting up in fear of the glitch hurting the transmission prematurely.

 

E4OD is a great transmission, but the electronics are 30 years old. Keep up with the small problems before they turn into big problems.

 

actually the stiffer shifts are better for your transmission because it doesn't slip the clutches as much. Ford designed it that way so if any of the number of things that break the signal path goes wrong it wont eat your transmission. Comfort is the only reason for smooth shifts. As long as it shifts when its supposed to, you're fine.

 

Update on this- WE did purchase a new teca and it did not change anything. Still erractic shifts and no codes being displayed even though OD light would flash. We took a break from it and did some research and this morning had an idea. We also have a 95 F250 that is a manual transmission. The research i had found showed the PSOM units to be the same. The 95 has 300k on it. Being a manual, we had no idea how the outputs to the teca may be since they are not used on the manual but we figured it should do something different and would only take a little bit of time to know.

Caveat- While the connectors are the same, the only difference between the two clusters is the tach module on the 95 has 4 connections on it and the 92 has 3 connections. In light of that, we installed just the psom module into the 92.

That fixed the shifting issues and allowed codes to be checked with the reader for the first time since this started. Both psom modules had the same CAL code for the tires as well. The 95 had never been programmed but the 92 looks to have been programmed at least 4 times.

So, the next step is either sending it off for rebuild or finding a used one. $139 for tested rebuild with correct mileage & 2 year warranty does not sound terrible so that is probably the route to go.

I will give a final final update once we get the end of it.

Things i learned in this is that a bad psom will prevent the teca from sending codes which is something i have not seen linked in any of the forum research i had done. This may help someone else one day.

 

That's a great find. Thx for reporting your progress.

 

So it has been longer than i thought since i made the last post, but here is the end of it all.

We received the rebuilt PSOM back and the truck worked great for a day. Started out great the second day and then went back to its ways. Same thing on the 3rd-great at first and back to its ways. Contacted the group that rebuilt the PSOM. They asked us to check a couple things (most being what we eliminated earlier before sending the PSOM off) and those things were ok. As a sign of good will to them, we again put the PSOM in the 92 from the 95 and it worked great for two days. On a side note, somewhere along the way, my son mixed up the two cluster bases during the PSOM swap and installed the 95 cluster into the 92. At the end of the 2nd day, it had a dead batteries when he stopped to get fuel. One of 3 differences in the clusters of the two years is how the exciter wire for the alternator runs through them. Neither truck was charging at this point but it only took about 30 minutes to figure out what happened but I digress. The transmission was working right the whole time.

We sent the rebuilt PSOM back to the rebuild company and asked them to double check it. When they returned it the second time, they included a note to say that when the PSOM got hot, the processor inside would shorten the square wave signal from the VSS and that was what causing the issue. No charge for the second look and they did a great job. Customer service is only by email, but they do respond when you send them one. PSOM has now been in the truck for 2 weeks and truck is doing great. It took a minute to get here. We made some mistakes, but that was the only part and some time troubleshooting. I intentionally put a code in the truck to see if it would display codes now, and it does that as well.

It is nice that it works correctly now. I find myself listening when he leaves the drive because i could hear the stutter shift it did going to second when the PSOM was defective.