1997 Dodge Ram torque converter code p0740

Hi
Need a scan tool to do diagnostics. What can do check fliud level good color red clear?PTU connection tight on side trans? Are tires larger than stock?
Let me know
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The transmission fluid looks red and clear, connections are tight, tires are stock 265 75 r16, But there is a problem with the torque converter locking up. I have a scanner and got code p0740. What next?

What you have is a code reader a scan tool interfaces with PCM and can diagnose failures in control circuits.also will need to have pressure tests done on trans to determine if pressure loss is causing problem.

I Have a code reader, it may be a scanner as well, I payed $100 for it. Also I am ready to do a pressure test. can you give me specifications. Thanks

Scan tool needed is like the one I use a Snap on MODIS and costs $9700.00. As for pressures check Drive /overdrive see figure to ID tap.

Remove overdrive clutch tap install 300psi gague. Have vehicle wheels off ground trans in drive increase engine speed untill 3-4 shift NOTE pressure 68-72 psi at closed throttle and 90-120 at 1/2 to 3/4 throttle MAX 130psi. If pressures not reached the internal fluid loss

I did a pressure test on the overdrive clutch tap, and when in drive, the pressure was around 50psi at closed throttle and at 85psi at ½ throttle, and pressure readings where the same going down the road. Do you think fluid is getting by a seal somewhere in the transmission?

Yes valve body or lockup clutch in torque convertor

Do you think I should replace the torque converter? Is there any thing else I can test or pressurize with the pan off? If there is, give me a diagram and spects and I will do it. Thanks!

With pan off check for clutch material, silver metal shavings. Also pull off TCC solenoid see if sealing ring is good and plug on shift valve is in and tight. Sending diagram but it is transfering small try and move to like a Microsoft works see if you can enlarge

#25 and #15

There is a little metalic sludge on the magnet in the pan, I see this on a lot of transmissions and seems normal. Solenoids look fine and operate with 12v applied. checked connections and wire harness and there are no opens. It could be the valve body or torque converter like you said, but which one? I think I will replace the torque converter soon.

with no other shift problems and there is a pressure increase that trys to 3-4 shift think fluid leak could be Teflon "O" rings on input shaft . When you pull Torque off inspect rings if cut or deformed that's problem. If lock up piston was faulty would see A LOT of metal in pan.

Ok, thanks I will look at the seals.

I am putting the valve body back together and I found a small steel ball in the pan I drained fluid in. I dint see it come out during disassembly. I don't see where it goes. I dint think that this transmission had check balls. Can you check and see? It is a 46RE, thanks

See diagram ues a dab of Vasoline to hold in position

I have the torque convertor off now, and I see the O ring in the bottom of the torque convertor looking down the hole. It doesn't look bad, but it is hard to see.

I might try too pressure test the torque converter to see if I can build up pressure on clutch piston just for fun. I think I will machine a piece to apply pressure. Is this something that is normally done to converters after taking them off?

I pulled the pump off to look at rings on imput shaft and one is steel and the other one is Teflon I am going to replace them both before mounting transmission.

Been working was off line but yes air checking torque is done everytime a trans comes apart. but takes anadapter to get to line input. You can see on top end of input.You could have a Trans shop check torque save you hassel and expense of pulling back or replacing.

I put two new seals on the imput shaft and blew back into the transmission, and a lot of air seem to be getting around them and coming right back in my face between the two splines, like the ones I took off. Is this normal?

NO not normal take converter to trans shop have it tested

A transmission tech looked at it, and pressurized it with adaptor and said it was within specs. So I mounted the trans back up with a new torque converter and imput shaft seals, and truck runs fine. RPMs drop like they should when converter locks up.

Every thing is fine except the "ABS and brake light" came on when performing test on day one. I had the rear tires off the ground and was spinning them at high speeds. What kind of reset tool do I need, or can I reset them another way?

GREAT NEWS glad to hear
Yes ABS set when revung wheel off ground. Either pull ECM/PCM fuse or diconnect BATT should clear

I disconnected the battery and the lights went out, thanks. I am having another problem with the cruise control, and shifting is erratic. I got a output shaft sensor code. Can I do a circuit check or should I replace the sensor?

What was code ? 0720? speedo accurate?

I had a spring backwards on a lever on the transmission that might have been causing problems with the output speed sensor. The check engine light has not come on for a while, but there is still a problem. Its hard to tell if its the transmission or engine performance. I have recently had plugs, plug wires, cap and rotor replaced. It feels like there is binding and releasing, There is a little bit of poping noise on acceleration, but motor is fine reving up in park. I had the transmission out a two weeks ago. What should I try next?