The OEM E4OD torque converters are very weak, and not just from clutch slippage, get an aftermarket one with as many upgrades as you can afford, especially if you plan to increace the output of the engine later on at some point.

 

I tried to do the manual torque converter on my truck and got into some problems. My truck is a 90 f250 with E4od and 460 engine. I had previously installed a billet tc and Transgo shift kit about 7 years ago.
Truck was shifitng fine, but my tc started unlocking and locking at hwy speeds so I tried to install the manual tc lockup switch. Right away, the transmission acted strange. It was slipping badly, like I was starting in 2nd gear. I would not get any tc lockup so I removed the switch. Now it still acts like it is starting in second, and the OD button doesn't do anything. I also don't have od anymore. I would appreciate any advice on things to check. The fuse in the panel looks OK and the OD light is lit and never flashes.

 

If the OD light is lit but not blinking than that means the OD is OFF and by default (programming) your TC should not lock.

I am not sure what would happen if you install the switch and try to lock the TC with the switch while you have the OD button in OFF.

The OD and TC Lock-up are interrelated in that the TC will unlock automatically when OD is botton is turned off (i.e. light on)

Have you checked your TPS (Throttle Position Sensor) for any flat spots)? Is your Engine TACH cutting out sometimes?

Lastly Have you changed your VSS, they do go sometimes and on pre-92 models they were still located in the tailshaft housing of the transfer case.

You won't necessarily get any flashing OD light on an intermittent sensor problem that is triggered by the VSS, TPS, or Tach Sensor.

A code scan would help to identify your problems.

 

the converter doesn't lock until the trans shifts into 3rd gear.
the od cancel button does simply that.it doesn't alter the converters un/lock state at all.
if your getting an improper lockup condition,inspect the tps (for diesels.)
for incorrect gear starts,inspect the MLPS.

i bet Pete (back in '07) had a bad solenoid pack plug causing his issues.
fairly common that the plugs get dirty,loose because they were never snapped back in from previous removal,or even due to this plug failing completely perhaps because someone left the heat shield off etc,and the exhaust melts the wiring covers and then wires are all exposed and it causes all kinds of fun.
they sell a e40d solenoid pack repair plug to cure the issue.

of course if this only happened when he had his trailer plugged in,then i guess he likely found the issue there easy enough.

 

Thanks Hamberger for the advice. I will take a look at the sensors this weekend. I also will check out the MLPS as the gear indicator doesn't align on the column. I have replaced the VSS, TPS and shift solenoid body last year, but I shouldn't rule out anything. Do you think the EEC relay would be worth checking? I just want to get the transmission functioning normally before I try the Manual TC lockup swith again.

 

I got her working again. I replaced the MLPS but it didn't help. Then I replaced the solenoid body and the transmission is shifting properly and the OD cancel switch is working properly. I think that I shorted out something in the solenoid when I tried to install the manual TC lockup switch. I converted the wiring back to stock for now. Thanks to all for the advice.