Rebuilt E4OD 800 miles ago now having problems

[Greenie]

Update... Installed a new Bosch alternator. Started truck and tested for AC voltage - zero AC. Drove truck 15 feet forward out of the garage and into the yard and let idle. 10 minutes later I check, belt tracking well and dash voltage gauge where it should be. Then I see the overdrive light flashing. I pull the fuel shutoff wire and the truck shuts down. I leave the ignition alone. I hookup the scanner to the two connectors under the hood, driver's side and trig the accelerator pedal as directed. Nothing. No marble rattling sound that these scanners usually cause.
I'm thinking that the TCM must be bad. I can get a replacement but the darned thing sounds like Ford built the truck around the TCM; hidden between the inner and outer fender.
Since the transmission faults sitting still I'm ruling out the speed sensor and the RPM sensor looks good. Since I've lost 2 replacement stereos (the last quit with a odor - not wires as much as a chip) I'm guessing the AC ripple may have damaged the TCM.
Thoughts ????

 

[Nero]

If I remember right, you don't hook up the singular wire when trying to read codes, grounding it out puts it in output test mode and won't list codes.

As another option, O'Reillys sells rebuilt control modules.
I found out when pressure washing the underside of my in laws truck, that the brake pressure switch on the brake line on the drivers side frame rail, has a constant hot wire. It's used to cancel the cruise, and apparently the switch had shorted out and took out my tcm. Ended up cutting the connector off and taping it off.
Took me 2 TCM's to figure that out...

 

[Greenie]

The always hot brake switch wire caused some fires and was the reason for Ford to issue a recall notice. I disconnected it years ago. How big of a job is it to replace the TCM? I can't even see where it is.

 

[Nero]

It's not that bad, just a little cramped around the wheel well. Best if you use a 1/4 ratchet socket.
I can't remember if it's a 8 or 10mm, that holds the harness to the tcm, then two bolts that hold it to the firewall. Just slides right out.

 

[trackspeeder]

Use a 10MM socket to remove the bulkhead connector under the hood.
To pull the TCM. Remove the driver side kick panel. When you take it out. Check for water damage.

 

[Greenie]

Thanks.

 

[Greenie]

Update... Replaced the TCM with a NAPA reconditioned TCM. When I first started the truck the overdrive light flashed but when the engine was shut down and restarted the light remained off. I took the truck for a short test drive - about 10 miles and the overdrive light remained off and the transmission shifted properly. The last time I drove the truck (with the original TCM) the light flashed repeatedly even after shutting the engine off and restarting so it's definitely better now. I am hopeful this fixes it for good.

 

[Greenie]

Drove the truck about 170 miles today and not a single hiccup. No flashing OD light, no slamming up shifts. Even aftermarket radio #2 - a Pioneer that shut down several times worked flawlessly today. I never would have known about AC ripples without the knowledge bank available here. Thanks for helping me keep this 30 year old truck running!

 

[Cant Write]

Thanks for this thread, neither would I have known about the AC ripple. Just measured it in a Fluke 117.

It would not read: just OL.mV. So one less thing to worry about!

My van does have a “Driveworks” remanufactured alternator out of Mexico.

 

[XOLATEM]

It would not read: just OL.mV.

Didja try some of the other AC volt ranges...?

Best I can figure ..OL means 'out of limit' or something thereabouts...

 

[Cant Write]

Didja try some of the other AC volt ranges...?

Best I can figure ..OL means 'out of limit' or something thereabouts...

I would have to read the manual, but it auto-ranges. I don’t think the Fluke 117 is an American made meter, but it’s a decent $100 meter.

someone with more experience than me can chime in, but OL in this case means it’s so negligible that it is none or basically zero AC ripple.

Prior to hooking the leads up I could watch it “hunt” in mV’s. As soon as I touched the negative lead to battery, it went OL. On a van I needed to be mighty careful my positive lead didn’t play with the serpentine belt.

 

[Reggie f250]

You should have some sort of reading. 20 mv is about average. I've never seen less than 10mv. 50 is supposed to be the upper limit. More than that usually messes with the electronics.
Or mabye you have really good diodes in your alternator.

 

[gnathv]

Download the manual. In mv it auto detects and reads ac or dc. Your OL means overload. Put the meter in ac volts not mv and see if it reads anything. AC scale will read down to 60mv.

 

[Cant Write]

@XOLATEM @Reggie f250 @gnathv

Thanks for prodding me further. When I put negative lead on body ground or battery negative lead it went OL.

When I put it on the alternator case or accessory bracket bolt it read 22.3mV.

Thanks again!!

 

[Greenie]

When I tested the alternator I did not set the engine speed to 1,500 but instead had it around 800 RPM with the high beams on. I'm not sure if the AC ripple varies with engine speed or if there are random spikes when the AC voltage increases even higher. I had my Fluke 323 amprobe set on 20 VAC. Regardless, with the replacement Bosch alternator AC is zero.