transmission codes P7128 and P0760 any help?
 

I have a 2001Dodge Dakota sport with 45rfe Transmission 137k miles. recently went in to limp mode, hook up code reader and found codes P7128 and p0760. I replaced solenoid pack, both rpm sensors and pressure sensor.changed oil and both filters. After clearing codes it seems to shift perfect but eventually goes back into limp mode. any thoughts on what else to check or what it could be?

Do you get new codes when it goes back into limp mode? Is the p7128 a typo? Is there a specific scenario when it goes into limp mode or is it random?

Yes sorry that’s a typo it’s p1728 and p0760 in that order. Same codes pop up when I clear them and no weird scenarios. Think it might be something electrical not sure. Any thoughts on where to look

Well the p1728 is a bad code to have. Was the truck slipping before the repair? Your going to want to drop the pan and pull the valve body. There will be three valves. Make sure they don't have broken springs and don't have excessive play/jammed. The issue is related to the torque converter clutch not engaging allowing it to slip. Your likely going to be looking at a pretty big job. It could be the valves or the torque converter itself.

Thx supa, I never noticed any slipping prior to limp mode but I could be wrong. I've already taken a look at the valve body, the springs are fine and the plate isn't warped or broken. as far as the valves I took them out and seem ok not sure the tolerances but weren't hanging up or jammed. I was leaning towards something electrical with the wire harness cause when I replaced the old solenoid pack there was oil in the harness like it got thru where the pins are. but after cleaning out good with electronic cleaner and new solenoid pack nothing changed.and no new codes. Like you said could be something mechanical like the torque converter clutch? I've repaired and tinkered with all my cars most of my life but when it comes to transmissions its a big learning curve. is the P0760 related to torque converter also?

The p760 is reporting a failed shift solenoid. Specifically the C one. Dodge packs them all into one unit so you can't really test them one by one. What I don't know is if the "C" solenoid handles lockup. If it does then that's the problem. Did you take a look at the harness and make sure it wasn't damaged when you had things out? I believe it sets a different code for a no response situation but it might be possible for it to only do a generic p0760 for no connection on a pin. I would look at the back of the connector and verify that non of the wires are pulling out. In case you didn't already I would recommend putting dielectric grease in the connector to help keep future fluid leaks from causing issues.

Thx Supa I’ll double check that harness. Not a lot of room to see much as you know. Am I able to change that harness if I needed too? I’ve already replaced the 2 small harnesses for the input and output rpm sensors. The wiring didn’t look great

The transmission harness is combined with the main harness sadly. You could manually cut out the damaged bit and replace it if you can find it. I would recomend you use these type of connectors if the total number of wires damaged is low. They are extremely good at keeping out corrosion and have built in solder to ensure proper connection.

https://cimg7.ibsrv.net/gimg/dodgefo...8adb35d063.jpg
Hey supadoom, just wanted to give you an update on my transmission adventure. I knew we were on the right track, here's a pic of my harness. also had to replace the TCM

Pic is TINY. Can you upload something larger? :)