Engine Issue or Torque Converter issue?

Fredrickson

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Finally got around to taking the truck out after the last problematic run I posted about.
This time I was driving during the day, without rain, and with the bad injector replaced.

I googled the issue I am having, and some results point to the engine, others say torque converter.

VEHICLE: '94 7.3 IDI N/A, E4OD in an E350 ambulance, 245k miles, gvw 10,500
SYMPTOMS:
Starts fine, goes through the gears, but when it gets to overdrive, if on a hill/incline or has a load on the engine, it feels like there is a sputter/stutter and appears to lose some power. The truck shakes in time with the engine. (No extra/new noises when this happens)

If I hit the O/D switch on the gear shift to disable overdrive.. it downshifts, revs higher, and the issue goes away.
If I am on level ground or going down hill, O/D behaves and I can get up to highway speeds.
I didn't notice this "stutter" if I load up third gear.

I also noticed the volt meter (not the basic dash gauge...an aftermarket one) would bounce around.. drop into the 8-10 volt range and go back up, and the ammeter would dip in to the discharge range when the sputtering was happening, and go back to normal if I disengaged O/D.

The speedometer needle would wiggle a bit as well, even though the speed was fairly constant. 45mph-ish

I drove it 40 miles (mix of local and interstate) to drop it off at a shop yesterday to get my state inspection and have the timing checked while it was there.

I forgot to do the brake test to disengage the T/C before I left it.. so I am not sure if that would have shown me anything.

(The transmission has a deep pan on it, and the fluid/filter has maybe 5000 miles on it.)

Many of the google results describe the same problems, but are running gas engines, and blame spark plugs, wires, cap, rotor, or even a blocked catalytic converter.

Other results say the t/c and this happens with high mile EO4D's.

I do not know if this is the original trans, a rebuilt or a swap.

The O/D light does not flash or show any signs of problems.

Thoughts? Opinions? Things to check?



Thanks!
 

Black dawg

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torque converter shudder generally happens as the converter lockup shift takes place.

your description sounds like a cylinder contribution issue to me.
 

quickster

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Just a thought, but check the connections to the brake lights. Iirc if a brake light is out or has a bad connection the lockup will act up. Also check the switch on the brake pedal. Shudder can be heat related too. Pull off the inspection cover on the trans. If the TC has some blueing, it's been overheated .
 

Markminyard

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I could see it being a torque converter issue or shift solenoid shorted. That could be the cause of the major voltage drop you are seeing. I know that the wiring harness that plugs into the transmission is known on e4od transmissions for the installation coming off and the wires touch. This is normally right at the the plug. Sometimes even engaging two solenoids at the same time that isn't supposed to be engaged. Also the tachometer and speedometer should be smooth and working correctly or the transmission will not work properly. And a miss can cause transmission issues also but not the voltage drop you are speaking of. If you think it is the engine. You can loosen one injector line at a time and listen for a engine tone change. If no change that is the cylinder you need to look into. Possibly a injector , valve issue or rings. You would need to do a compression test. But imo I think it is electrical.
 

Fredrickson

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I really hope it is something like a worn wire somewhere.. rather than rings or valves..
I replaced the solenoid pack about a year ago.. and the injectors are were replaced very recently.


Would timing mess with overdrive performance?
 

quickster

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How fast are you traveling when it shifts to OD? Does it gear hunt between 3rd and OD, back and forth. The voltage at the FIPL might not be set correctly. Also make sure the plug on the trans, pass side behind the heat shield is spotless. Goes to the valve body iirc. Haven't had a E4OD in a bit.
 

Fredrickson

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It shifted at around 45 mph. pretty smoothly, no hunting.
I'll check all the connections, hit them with some electrical contact cleaner
 

trackspeeder

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Before going crazy with the tranny. Fix the electrical issue first. Any voltage drops will make the E4 go nuts. The TCM is not tolerant of fluctuating voltage. I would start with the alternator because the TCM or solenoid pack are not able to draw down that kind of power.
 

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