Calling Dodge experts! I'm just about at my wits end with this truck trying to get this issue fixed. I've been working on my own vehicles my entire life and have never run into an issue I couldn't fix. I've scoured the internet for over 20 hours now looking for solutions and have come up empty.
I just bought a 2001 Ram 1500 5.2L auto, 4x4. 125k miles When I try to start from a stop this thing will hardly move. On flat ground I can floor it from a stop and it revs to about 1500 and slowly takes off like I'm towing a big trailer. If I stop on a hill it doesn't have the power to get moving again, it just revs to about 1600 and that's it, wont move. Once it's moving it seems to have no trouble. Seems to be under say 2500 rpm it just has no *****. It starts, runs, idles perfect no issues there. No rough running, bucking, surging, missing, pinging whatsoever at any rpm or speed. NO codes. Once I'm moving and rpms are about 2500 it really picks up and accelerates up to redline with tons of power, like push you in the seat power, so its not a plugged cat converter. It shifts through all the gears fine, I can manually move the shifter into 1,2,D and the trans shifts into first then second then third, no clunks, no unusual revving or bogging. OD on/off works, torque converter locks and unlocks on the highway properly. Fluid isn't burnt and at the proper level. I've owned a 96 ram with the 5.2 and a 95 Grand cherokee with the 5.2 so I know what this engine is capable of.

Things I have already tried: drop trans pan, replace fluid with new ATF+4. Replace governor solenoid, adjust bands.
Replace MAP sensor, IAC, coil, plugs, wires, cap, rotor, Plenum plate gasket, manifold gaskets. I tested the TPS with a multimeter, voltage is from .5v to 3.75v fully closed to fully open. Compression over 140 psi all cylinders. I've adjusted the kick down cable all over with no change. Trans cooler lines have the check valve removed. I had a mechanic friend come over with his shops fancy snap on scanner and he says all the sensors are good according to the scanner. O2 voltage sweeps up and down properly. Fuel pressure is good 48+PSI. Throttle body is clean as a whistle. The brakes are all new and aren't sticking.

The only thing left I can think of without randomly throwing more parts at it would be checking the timing chain, actually replace the TPS instead of testing it. Fuel sync? (wouldn't that cause rough running though?) Check the not adjustable timing? Crank sensor? Engine computer? Possible bad torque converter? Replace entire trans?? The engine computer does have the death flash (done in 2003) but I doubt it would cause this issue.
The nearest dodge dealer is over 2 hours away and I really can't afford the $100+ an hour for them to throw parts at it as well.
Since I bought the truck like this and I can't get a hold of the previous owner I have to assume any number of crazy things have been done to it.
Please help before I set fire to this truck!! Any and all suggestions welcome.

 

Logged catalytic converters?

 

well, you have done pretty much everything I can think of..... My first question would be, is it actually starting out in first gear? Even if it isn't, it should still have more ***** out of the hole than that. You should be able to at least chirp the tires, if not smoke them at will....

Try this test. Unplug the 8 pin connector on the trans, drivers side, about halfway back. This will disable the electronics in the trans, so, NO automatic function at all. None. Zero. TCC and O/D will also be non-functional. So, start in first gear, shift when you need to, (both up and down.) and see if things feel any different.

Also, make sure the rear brakes aren't adjusted too tight, and that the SHORT shoes in on the front...... Make sure the front calipers aren't hanging up.

Let us know what ya find.

 

Cant be the cats, the trucks revs up fine once moving, has lots of power on the highway.

 

Thanks HeyYou, I checked the trans, I only see a single 3 pin connector on the driver side of the trans. Then another 2 pin at the rear of the trans. Maybe the 3 pin?
Also I've had the truck up on jack stands with all 4 tires in the air and the brakes are definitely not sticking. One interesting thing I noticed though was the tires would still spin in neutral, though I could stop them with my hands.

 

The 3 pin is neutral safety switch. It's in top of the tans right behind gear selector level. It's on that flat part. It's black and is a cylinder looking plug.

 

Here is what the connector looks like

Here is where it's located

 

Found it, thank you. Hidden behind the shift cable.
So driving with the 8 pin connector disconnected, shifting the trans manually between 1 and 2 did nothing. shift between 2 and D works. Trans feels like its stuck in second even when shifting into 1. But with the 8 pin connector reconnected, I can shift between 1 and 2 just fine. Still the same sluggishness when in 1st. Also feels exactly the same sluggishness when in reverse, connector connected or not. Is this the expected result?

 

No. Unfortunately if it didn't shift from 1 to 2 without electronics, you have a mechanical problem (probably needs rebuilt). You probably think it's shifting from 1 to 2 but it's really not.

 

No. it isn't.

If you aren't getting a shift from 1-2 when you move the lever with the connector out, there is a mechanical problem in the trans. Something is stuck. You *might* be able to solve it by cleaning the valve body really well......

Did you also replace the governor pressure sensor while you were in there? What brand governor solenoid did you install?