I've got an E4OD tranny in my E150 Conversion van with just over 200,000 miles on it.

My transmission started shifting hard (1-2, 2-3, and 3-4) and after clearing some codes it returned to shifting normally. As I recall, the only trans related code was 628 (excessive torque converter slip). I was using a borrowed Snap-On 2500 scan tool to test with. I kept it hooked up and took the van for a drive.

I drove it for about 15 miles watching the scan tool and waiting for the TCC to lock up. It did not try to lock up at all. I was watching a line that said something like CCC TCC command = NO. It never changed and I had the van going up to 60 mph in OD.

Now the OD off light is not flashing. It hard sometimes to get the van out of OD while driving. I will push the button on the end of the shifter and nothing happens. Usually if I put the van in neutral and then hit the switch it will light the light, but even sometimes that does not work.

I've have seen a few post about bad TCC's and something about solenoid units being bad. If I were to take out the solenoid pack, is there a source for a schematic with a pin out so I could test the solenoids myself, or do you need some special tester?

Do you think it is worth putting money in a van with 200,000 miles on it? It has been a good van, but I'm not sure how much of a savings I will get in fuel mileage if the TCC locks up?

thanks
Andy

 

Well if its a good van, put the money into it IMO. In the long run you will be saving money compared to a non-locking TC. As for testing the solenoids I wouldnt know, but I am sure Mark K. would be able to tell you on that one for testing the piece.

 

I'm not sure on the testing procedure either, but if the converter is not locking up you will cook the trans sooner or later. It's designed to lock up and if it doesn't, the slippage of the converter will heat up the fluid. Left unchecked long enough, it will eventually damage the converter and the trans and then you're looking at a rebuild.

I would avoid driving it until you get the lockup fixed.

 

Thanks for your replies. I will be working on it in the near future.

I think the first thing I am going to try is removing the electrical connector on the side of the tranny and checking for corrosion. I know the rest of it is pretty rusty down there. I live in Michigan and they really like to throw the salt around in the winter.

thanks again
Andy

 

When the computer sees a problem with the transmission it will go into a "limp mode or failsafe". What this means is the computer raises line pressure and inhibits lock up. That is why you dont have lock up, and explaines the hard shifts.
The code 628 is a killer for a E40D, it sets because of excessive converter slip. The computer uses engine rpm and road speed to guage converter slip, when it is out of range for 5 times the computer sets the code a goes to limp mode. In all the cases I have delt with a E4OD with a 628 the converter was bad and half of those, the pump or another part caused the converter to slip and fail.
Sorry it will most likely have to be rebuilt with a converter, and make sure they change the spring for the converter regulator valve that is located in the pump. A small shift kit would work well for this kind of problem with the E40D.

 

It's probably not the solenoid. The torque converter lockup clutch piston was prone to cracking. Once it cracks it doesn't hold enough pressure to maintain lockup and code 628 sets. The only cure is a new torque converter.

 

But the scan tool that was being used is showing that the converter is never being commanded to lock-up. A (possibly) sticky/faulty hazard light switch can cause that; something like that will keep the converter unlocked, causing the transmission to over heat and go into limp mode. This could be a possibility...no?

 

The converter wont be commanded on when the trans is in fail safe, you would have to clear the codes then watch for TCC command.