I have an 89 F250, 5.8L with an E4OD. Bought

it recently. I had what felt like converter shudder. Added Lubeguard shudder stuff...nothing. A mechanic buddy with a lift helped me install a new O'Reilly converter. It shuddered about 5 min into the first test drive. Added more Lubeguard...nothing. Replaced the converter AGAIN today with a warranteed one from O'Reilly and it shuddered on the test drive. What gives? Truck has 115k actual miles. Shifting is OK.

I changed the fluid before doing the converter the first time. I did it again today at the same time the new converter went in. The old fluid (less than 200 mikes old) looked a little dark. Not so good. All new fluid the second time around.

I'm getting tired of pulling this beast of a transmission. Is it toast? What else could be causing this problem if not the converter? I'm just about ready to put a T18 in it. And maybe a 300. Not a fan of the 351 gas guzzler.

 

I’m not the E4OD tech but I’m sure someone can help you diagnose what is wrong if that is what you want to do. I see you have another thread asking about the T18 swap. There are electrical and hydraulic testes that you can do to figure it out.

IMO, you aren’t going to save any fuel by losing 51 cubic inches in a heavy 3/4T truck shaped like a brick. If you do admit defeat and go with the T18 you’d also be losing overdrive so that isn’t going to help either.

 

Converter shudder or a miss fire? Any codes?

New plugs, cap and rotor? Wires OK? EGR system working correctly?

Are the plug wires routed correctly? Maybe you have a cylinder cross fire issue.

 

PO did a lot of parts swapping tracking down what he said turned out to be a bad ECU which he replaced. I have the old one and the other old parts that are presumably still good. Gonna try swapping them out.

I got it with a blown head gasket. Plugs on the other side looked great, but I'm suspecting I have a head gasket on the other side too. Radiator won't stay full. Blows coolant into the jug. Doesn't run hot though.

When I put it all back together after the head gasket I left off the whole smog system. It was rusted out on the back pipes. No emissions here.

The EGR is still on it, but I have the valve unplugged at the vac port and the valve electronics plugged in since I don't have an EGR delete electronic plug thingy. The check engine light is NOT on, so I haven't looked for codes. All unused vac ports on the engine are plugged.

Could my EGR be causing this? Should I get the delete plug for the electrical connection? I think the correct vac port for it is now deleted with the smog. Connected to the manifold it runs like crap. Disconnected it idles pretty well.

It doesn't run bad, but I also have a 95 and 98 Chevy, both 350 with noticably more power than this 351W. And I had a strong 351W way back when. The more I work on this truck though there more I'm convinced that the mileage really is 115k though.

 

Mine was shuddering occasionally. There was no check engine light on, but there were stored codes. One of my codes was for the throttle positioning sensor. I replaced it and my shudder went away immediately and completely.

Check your codes.

 

You can the solenoids plugged in to fool the computer; Leaving the vacuum hoses disconnected. You can put a thin piece of metal between the EGR valve and the intake manifold to block off any flow. There is no need to buy the EGR delete electronic plug thingy.

As GoinBoarding said, eliminating the (engine) electrical, ignition and fuel systems as the cause of the driveline shudder is a good first step before condemning the transmission.

 

Offhand, I'd guess a burnt exhaust valve. The 390 in my 75 does the same thing, I initially thought it was something in the drivetrain.

 

Check codes. No CEL doesn't really mean much. Something like an Innova 3145 code reader makes this less error prone than counting flashes and would be money well spent.

I wouldn't swap anything until you read codes. Too often parts swapping confounds the issues by introducing additional variables. New parts doesn't mean they are good parts.

Check fuel pressure at the rail while it is shuddering. Low pressure under load could cause a miss and contribute to low power and low fuel economy. Might feel like converter shudder.

These flat tappet 351W engines had pretty lame camshafts, so even running correctly they probably are slow.

 

You might want to check fuel pressure, a dirty fuel filter could cause engine shutter.