E40D Help!

[focker]

So my uncle has a 1993 or 1994 f350 with the e40d in it it was driving decent then it started not shifting right and shuddering! I told him it was a wiring problem but he had it rebuilt and put it back in and low and behold it is still doing the same thing! Any ideas on where to start looking at 1st?

 

[ISPKI]

Is the truck an IDI or a PSD?

Can you describe the issue in further detail? What was the truck doing right before it started shuddering and not shifting right? Did the O/D light come on and start flashing? Is it doing it all the time or only on hard pulls? When it shifts, does it "buck" really hard?

Right off the bat, I would check the harness plugs at the transmission and make sure they are tight and clean. Then I would check the FIPL(TPS) and make sure that is connected and operating within the correct voltage range. I would also suggest checking the VSS mounted on the rear axle and finally, check to make sure the dome light in the cabin works.

 

[trackspeeder]

Check for codes.

 

[gmtech68]

I'm curious what the significance of the dome light is. What circuit is it tied to

 

[ISPKI]

I'm curious what the significance of the dome light is. What circuit is it tied to

Supposedly the dome light shares a little 5a fuse with something that sends a signal to the transmission. Not sure if its year or model dependent, I have only looked into it for my 94 F-Superduty so that may not be the case on other models but I have read that if the dome light pops the fuse or has a shoddy connection, it can disrupt the signal to the transmission and cause it to slip into limp mode.

 

[gmtech68]

Anything is possible. Good to know.

 

[c_silva88]

Supposedly the dome light shares a little 5a fuse with something that sends a signal to the transmission. Not sure if its year or model dependent, I have only looked into it for my 94 F-Superduty so that may not be the case on other models but I have read that if the dome light pops the fuse or has a shoddy connection, it can disrupt the signal to the transmission and cause it to slip into limp mode.

I actually had an issue where screw for the positive on the done light made contact with the roof and grounding out and blowing the fuse putting my truck into limp mode took an hour on the side of road to figure it out

 

[ISPKI]

Well there ya go. Guess that dome light fuse could be low hanging fruit. I know mine has a loose fitting socket which causes it to flicker a bit when I leave the door open working on something. I should probably just unplug it before it burns out and causes more issues.

 

[aggiediesel01]

Also don't forget to check the brake light bulbs at the rear including the 3rd brake light if your year had one. An imbalance in the brake light circuit due to a bulb out can mess with an input to the TCM.

 

[Kimquattro]

Also check for broken pins on the shifter solenoid. Mine had broken pins and had some of the same problem as you describe