I hope someone can help me, I'm new to the forum so please bear with me. I have a 2004 e250 with a 4.6 that I was told had trans issues from a mechanic that had looked at it previous to me working on it. When I drove it, it had no reverse, first was fine, second was a hard engagement and was slipping. Apparently the last guy that looked at it pulled the trans pan and found debris in the bottom and said it needed a rebuild. This is when I got it. I had a 2002 e250 with a 5.4 also with a 4r70, But the body was in rough shape. I pulled the trans from the 02 and put it in the 04. The 04 is now running and driving again, but it won't grab 2nd gear until the engine almost hits the rev limiter. I can grab second manually and that's fine. reverse is working fine, also when it does grab second with the gear selector just in the drive position it slips it in and it makes squealing noise. i can't ever get it to grab 3rd. I changed the fluid, drained the torque converter when it was out, also changed the trans filter. It's filled to the proper level again with new merc V, checked in park with engine running. I had to add fluid multiple times obviously as the torque converter got filled again. I also should say that the speedo is not even close to accurate, it will read 20 km/h but it feels like I'm doin about 50 ish when in second. Also if I floor it in second then the speedo will just drop off all together. I already changed the vss in the diff. So my question is does anyone have any other suggestions?

 

What codes are you getting?

Vehicle speed is a critical input for accurate trans operation so I suspect your two problems are related. Given you just got the truck you could have one of many problems, it could be wiring or connector, a bad PSOM(speedo clster), or the PCM could be faulty or the wrong one for the vehicle. So pulling the codes should help narrow down the possibilities.

 

I only have a cheap $50 code reader and it can't find any codes. I know there has to be somthing, I guess I'll need to get it read and go from there. I know the pcm is original to the 04.

 

Sounds like something isn't compatible. Maybe @Mark Kovalsky can offer some better advice? Was anything left unplugged when you swapped the transmissions? Is the O/D Off light flashing?

If I remember right, some of these have speed sensors in the tailshaft.

 

I know that the method for reading vehicle speed with a 4R70W changed around that time frame. I don't know the details, I never worked on the 4R70W. Your symptoms are those of having the wrong vehicle speed, and I think it is due to the change I mentioned.

The short story is that if what I said is right, either that trans needs to be replaced or the trans needs to be rebuilt with the right hardware for your truck. And no, it was not a part you can just change. It is internal.

 

No dash lights at all on. trans was plug and play everything looked the same, the wiring from the pcm to the trans is the same in 02 as in 04, I compared the 2 schematics side by side. Got the codes read yesterday, all are cluster memory codes
u1123
u1059
u1027
u1041
u1262
this makes me think there is a communication issue between the pcm and cluster. Im thinkin the scp +or - communication wire from or to the pcm is broken or shorted. things like engine rpm and vehicle speed can be read on the scanner so the pcm knows whats goin on, the signal is able to get to the obd2 port but not to the cluster.

 

Does the vehicle speed read right or wrong? I remember there was a change to the number of holes in the drum that the output speed sensor reads. The connections would all be the same, but the speed would be way off if the drum doesn't have the number of holes that the PCM is expecting.

 

vehicle speed on the dash reads 20 km/h but the van is actually moving about 50 km/h

 

At some point the number of holes increased. It must have happened between 2002 and 2004. I think your problem is that the drum in your 2002 trans has four holes when the PCM is expecting a drum with more holes. This will cause the speedo to read very low, and also cause shift issues, along with other problems. The PCM uses the ratio of output speed to input speed to calculate gear ratio. It can't do this correctly with the wrong drum.