robert78.5

2001 2500 Diesel auto transmission, transmission started shifting later and later, now on occasion it will not shift up from 1st to second without putting into neutral .higher shifts are ok. .. I brought to dealer and they diagnosed the governor pressure switch and changed it. It helped a little but on about 25 % of the time it does show up again. I moved the wire from altenator to another location, I pulled the fuse for altenator, I unplugged the 3 main pugs on firewall module and cleaned them and replugged. I set the throttle cable to where it should be. I unplugged the speed sensor and cleaned out plug and replugged it. I also exchanged the transmission relay with another relay. From a dead stop it feels sometimes like it is starting out in 2nd gear... not sure what to check next. any suggestions would help.

would the Edge mileage max be affecting this? I have had it on for quite a few years now.

AlpineRAM

Sounds like you did your homework, which is good.

Does your speedo work correctly? Meaning, it shows speed at 5 mph and does not jump from 0 to 15 or 20?
If you got the jumping speedo check the speed sensor wiring from the axle to the PCM and the sensor.
If all is good there get some pressure gauges and monitor the line pressure and the governor pressure. Governor pressure should be around 1 psi per 1 mph.

robert78.5

I will check speedo for slow test tonight, never really noticed.. I do know it is out by about 10% according to my gps. I have to have needle at 110 to be going 100 km per hour

AlpineRAM

The speedo being "optimistic" is normal, but the second gear starts point towards a limp mode situation. If your trans is built or has a shift kit you may need to put a resistor into the governor pressure sensor supply wire.
Anyways, if the trans is stuck in first and the speedo is showing zero, you can assume that there is something wrong with your vehicle speed sensor on the differential or the wiring for said sensor.

robert78.5

Truck is 2wd and the speed sensor i cleaned was on the tail of the transmission, i do not see one on differential.

AlpineRAM

There should be a sensor on top of the differential. 2 wires from the sensor to the left leaf spring, going to the left frame rail and forward.

robert78.5

Ok I will check differential in morning, I purchased a new speed sensor for tail of transmission, I will replace tomorrow... Is there any particular readings I should be checking on wire harness end for sensor?

AlpineRAM

I'd just check continuity between sensor plug and PCM and go from there.
A visual inspection of the wiring where visible reveals the majority of the problems. A continuity check of the harness makes you sure the problem is not there.
I do not remember the values for the sensor on the 01, but it should be a rectangular signal when you turn the rear diff.

robert78.5

Changed transmission speed sensor, the old one had a large bulb of filings stuck to it. I found the rear diff sensor and removed it. I can see the copper winding clearly, looks like the plastic that covers the winding is broken up.Could this be a problem? I also took an ohm reading on rear sensor from pin to pin and it looks like around 30 ohm. I took truck out and at first i thought it was better shifting but after about 5 minutes I slowed down to turn down a side road and the same thing, would not shift out of first gear.until i put into neutral than back into gear than it shifted up perfectly. I removed battery cables and will leave it sit overnight. Hoping maybe something will set reset itself.

AlpineRAM

Chips and fuzz on the trans speed sensor is bad news.

I'd suggest pulling it again and see if new stuff sticks to it, if so you will need to tear down the tranny and find what is getting ground up in there.

The vehicle speed sensor on the axle should work if you get a speed reading below 8 km/h.

robert78.5

Nothing really helped,, still won't shift out of first sometimes,,,,, now i went to set the shift cable again and i lost the little white clip that locks the cable into place. Will it do any damage if i use it this way until i get a new cable or clip?

robert78.5

Ok,, I made a 4 hour return trip home yesterday and truck seemed to shift better, I did not have to upshift manually as often. Does having the shifter cable clip missing and the outer cable moving with the inner cable keep the line pressure higher or lower?

AlpineRAM

The throttle valve pressure is much lower with the clip missing, and the line pressure too.
Especially if you are on the go pedal you do torture your transmission.

Did you re-check the speed sensor for fuzz?

robert78.5

No I never pulled speed sensor out again, will have to wait for weekend.

high bid

Might want to check and clean every ground wire you can find.
Like stated above...looks like you've done quite a bit of trouble shooting. I'd take it to a trans shop and have them run codes and test pressures. The clutches can and will wear out... didn't see it noted above but you might wanna drop the pan, look for material, change the filter and fluid and run it again.
Hope this helps!