I have an E40D on my '94 with a 460 and 180k miles. Recently bought the machine, shifted fine for a thousand miles, and now I just replaced the leaky radiator and water pump (but hasn't been overheated, just increasing chance of cooling system failure if not addressed), rusty tranny cooling lines, and changed the ATF. The old stuff was on the brown and dirty side but not bad smelling or burnt. Changed 20 quarts using NAPA's ATF rated for transmissions needing Mercon type. Drove it a few miles, rechecked fluid level, all ok.

Today I drove 100 miles with no problems, parked a couple hours, then for the 100 miles back it's shifting hard with a solid clunk from 1st to 2nd, and also into reverse. I let it sit a few more hours at home after checking the fluid level again (in the middle of the hot indent on the stick so that's ok?), drove around a few miles and still doing it. Other shifts all smooth like normal, just 1-2 and into reverse.

Do I need to run a little higher on the fluid level, or is there some special lubey additive I should add, or something else I need to be doing? As far as I know it was conventional fluid before though it may have had some form of additive(s).

 

Is the OD OFF light flashing? Does the light come on when you press the button?

 

Actually the OD light won't do anything. Seems to be shifting in to OD but button won't let me lock off OD n light hasn't come on when push OD off button. Same as when I bought truck but may be the bigger problem?

 

The light not working is almost always a broken wire inside the steering column where the wires enter the shift handle. You can take the plastic cover off the column and either fix the wires or replace the shift handle for about $65.

You probably have codes stored in the PCM. When the light is working it will flash when codes are stored. You can buy a code reader that will work on your truck for about $25 and get the codes. Then I can help diagnose what's wrong.

 

Ok, I have a couple things going on and a couple codes.

565 canister purge solenoid but working that one out today.

212 loss of idm signal/spout shorted - So I didnt' do enough research here before replacing the TFI a couple weeks ago, and AutoZonedout gave me a grey instead of black, so I'm fixing that now.

The maybe big and scarry one I think... 628 converter slippage. Definitely feel more slip today than past days also. I don't have a tack on my dash, but I definitely have to give it more throttle for a given speed than a week ago. I'm hoping the ignition module will fix things but that's awfully hopeful thinking I think...

 

A bad engine speed signal will cause a 628 code. Fix that, clear the 628, and see if it comes back.