Transmission Shift Problems

[swvoss]

2001 7.3L F250, rebuild on tranny a year ago, started shifting hard and flashing the O/D light, had some concerns about the ten year old batteries and was told that should be done first by the rebuild shop. Put two new 850 CCA Interstate batteries in after coughing up the $240. Getting the flashing OD light and hard shifts, went by the transmission shop and had the codes pulled. There were three mentioned, P0603 internal control KAM error, P0470 Exhaust pressure sensor fault, and P1746 pressure control solenoid circuit.

Shop had me leave the truck and trying to figure out what is going on. So far they have put a new solenoid pack on and looking for an external electrical problem of some kind. not much good happened so far. they seem confused as to what to do inorder to find the problem or looking for something external that they can say is not their fault or not covered by warranty. Not good. Any ideas or input?

[swvoss]

latest update is the shop has run through diagnostics and ran down every possibility they can think of. (supposedly) I'm being told its not in the transmission, and that its an electrical problem external. How can an electrical problem external to the transmission cause it to shift hard??? something sounds fishy to me. yesterday they claimed they disassembled the column to look for a short in the O/D button on the shift selector. After that got them nowhere i was told they are thinking they need to sub-let this out to a specialist to do further diagnostics.

Any ideas or suggestions from the forum? thanks

[partsguy84823]

1) Get it out of that shop and to someone who knows what they're doing. It seems like this shop is doing a lot of 'guessing'

2) As far as the codes go...
P0603 - From changing you batteries (normal)
P0470 - Has to do with your EBPV sensor. It can generally be cleared up by cleaning
the ebpv tube. Instructions
P1746 - This is real internet diagnostics, but I would be looking at the transmission
range sensor. Or I would climb under the truck and look at the wiring
harness that feeds the trans. Either one of these will cause this code
and harsh shifting.

[swvoss]

thanks for the info, I called the shop and talked to them about your input. I knew they had already tried a new wiring harness and they confirmed this was done so I asked about a potential of the range sensor like you mentioned. it sounded like they had not looked at that yet, at this time they are still trying to locate a wiring problem.

I think part of the problem is they got stumped, its warranty work, and they are busy so it has been easy to put their mechanics on other vehicles. Supposedly they have a guy working on it today.

For my own knowledge if they keep giving me the run around, what is the range sensor and where is it located so i can follow up and see if they checked that out.

[swvoss]

had an advanced diagnostician find a wiring problem in the bundle between the PCM and the transmission. I would not have believed it until i went to pick it up and it shifts like it should. repair included some shrink sleeving and solder, still cost $300 but appears to be well worth it.

[partsguy84823]

Good to hear. Like I said, P1746 tends to be some kind of a wiring issue. A while back, before we got married, my wife had a Taurus that threw that code and it was the range sensor.

Either way, I'm glad you got it fixed.