Hard Shifting 95' F-350 7.3 4x4 E4OD Help???
In process of getting 1995 Ford F-350 7.3 PSTurbo 4x4 E40D when trans hard shifting problems cropped up. So several shops have been involved in checking it out further.
Shop #1 - Was a gear shop and they found no transmission error codes , said it wasn't slipping, but shifting too hard, and thought it should be serviced, inside checked, etc.
Shop #2 - Indy shop, familiar with Ford diesel pick-ups did a complete truck check-over, and the engine and truck was overall solid at 300,000 miles, no rust, no accidents, everything works, lots of new parts, etc.
BUT, they reported at times in their road test, the trans shifted way too hard into 2nd gear especially, and less hard into the others, but still too hard.
Recommended, trans service, dropping pan, checking further, and they talked with their associates at a good transmission shop, who said the same thing, that they needed to look inside, and do further diagnostics, etc.
This shop picked up no transmission error codes, but they got 2 on the engine and they said these were as follows:
#1 PO 472 = exhaust sensor pressure low
#2 PO 107 = MAP/BP sensor back pressure low output
So they wanted it to go to transmission shop for further testing.
The only other points to add at this stage would be as follows:
1. Truck had been sitting for 1-2 months and batteries had to be charged to start it, etc., but since it's been driven and going in and out of shops, it's been starting OK, but battetries will still be tested for replacement under warranty on them, as they are only a year old, etc.
2. Supposedly transmission was rebuilt once before, but no idea of when, so let's guess at 200,000 + miles???
3. Also, a comment was made that if the truck was under acceleration like merging onto the interstate, it would shift a bit less hard than being driven normally around town, etc.
Shop #3 - Truck went to well-established transmission only shop with clean room, rebuild experts, etc. They were saying that something was causing the pressure to be too high, and the shifts were not getting cushioned, etc.
They confirmed that going into 2nd was really hard (maybe OK for a Mustang at the strip they joked), and the rest a little less hard.
So they dropped the pan to check it as much as possible, etc. In general, it was really clean inside they said, no debris, etc. They cleaned the valve body they thought could be gummed up, checked and cleaned the springs, etc., solenoid pack checked, did everthing they could on the inside, at this point, etc.
Said it had stock type springs in it, and not a shift kit, etc. Cleaned it all out, did new filter, gasket, fluid, and outside inline filter replaced too.
Owner/expert of the transmission shop feels that the transmission is is very good shape, and is being told to raise pressures and shift hard by the computer.
He further says that he thinks the computer is getting bad input from the engine and other sensors, to cause it to communicate to the transmission incorrectly.
He further said that the electronic pressure control was OK, the TPS was OK (giving a reading in the 4.6 something range), the vehicle speed sensor was OK reading the right MPH, the OD was OK, and the trans was not in the limp mode.
So he feels it could be a combination of the MAP sensor, the engine temp sensor, a barometric sensor, and then maybe the TPS.
His advice was to get it to a 7.3 diesel expert to figure out anything wrong with the engine and its sensors, etc.
Shop #4 - We are trying to decide on which shop to go to next, and here is some additional information that we have picked up from others we have asked about this:
1. Expert diesel shop I know said the 2 sensor error codes above weren't that serious, that they go out a lot, and shouldn't affect the transmission hard shifting too much. They were most concerned if the OD was blinking and the trans was in limp mode, etc. They said if the trans shop thought the trans was good inside, that they estimated they could put in the 2 sensors above for about $300 total P&L:, and then go from there.
2. Another Indy shop had an interesting take I thought. They said they are work a lot on Fords, but in this case with the engine and the error codes, and the trans diagnostics so far, they could take my money, but they didn't think they had the full capability to diagnose it. They said they had a Snap-On MODIS diagnostic system, but in some cases it didn't have the right hardware or software to fully do everything. and they felt to do this right they would need to have a "Star or SuperStar II" system - which they said they thought all Ford dealers had, and maybe some diesel only specialty shops. And they thought that most other Indys would be lacking maybe 10-15% of the right tools to figure this out also.
3. I ran that by the transmission shop, and they thought it was a possibility, and said they knew a good Ford dealer to try.
4. Meanwhile, it came out that the MAP sensor had been changed out last year, with a vacuum line, so that was still under a warranty, so NAPA exchanged the MAP part, but there was no difference, in fact they did not even road test it. It shifted hard into reverse still, so they just quit.
Comments were made that maybe the MAP sensore was not getting enough vacuum ot too much from off the turbo, or wherever it comes from (please forgive me, I'm new to this, but a fast learner).
5. I talked to a Ford dealer, and they said they had the Star system, and thought they could pinpoint the problem with a P&L estimate for $85.
They also said they had seen this before and it's usually related to 2 things:
a) the MAP sensor (and things that are related to it then)
b) a temp sensor inside the transmission (and changeable by dropping pan)
NEXT: ??? At this point, we are trying to figure out the next move:
A) Take it to a good Ford dealer for the diagnostics and estimate?
B) Take it to a good Indy diesel shop that says they have seen this before and supposedly have all the right stuff to diagnose?
C) Contact Powerstroke friends for similar experiences, etc.?
D) Open to suggestions?
OBJECTIVES: Are to be able to confidently bet on there not being a major transmission/engine problem that is costly to repair to set things right. And that if truck is driven 700 mostly highway miles to get back to our circle of shops - that it will not create firther damage or be a safety or broken down in the boonies in winter issue, etc.
Apologies for the lengthy question, but I thought it best to be as complete as possible first time out, so I don't waste anyone's time with a lot of back and forth on the typical sequence of questions, what about this, did they check, that, etc.
Thanks very much for your comments in advance!