2010 68rfe trans trouble

[MarkP]

My 2010 3500 single rear wheel 68rfe auto trans is locking in 4th gear and sometimes its acting like its shifting into neutral between shifts, not just a couple hundred rpm flare but redlining type . If I shut it off and restart it it will usually unlock out of gear and take off normally until the first shift. Manually shifting it or using the tow haul mode doesn't seem to have an effect either way. If you drive it easy it pretty much acts normal, its when its pulling hard when it really acts up. I got 373 rear gears and pull 25000 lbs with it pretty regularly. I pulled the trans pan and filters, no burnt fluid and when I cut the spin on filter apart I didn't see any materiel whatsoever. Its got 96000 miles on the odometer so I took it to the dealer because its still under the standard power train warranty. They have ordered a new valve body, torque converter and rebuild kit. I am a little skeptical that it needed all of this and I am wondering if I will have more troubles as soon as it goes out of warranty when I become my own warranty repair station. I guess what I am really asking is has anybody been down this road and have any advice. My local dealer hasn't been real helpful when it comes to my diesels (this the my fourth one). It took 4 repairs and warranty claims to get them to clean the egr at 36000 miles, I tried to offer some friendly advice about what I had read on the tdr and they acted like I was from mars. Since then the truck has been right on. So I have my doubts. On monday I am going to ask the basic questions I have seen transenginneer and sag2 post on here, did they drive it with it a scan tool and monitor the tcc, was the pcm commanding it to unlock between shifts, line pressure values, any reflash or updates available. Any more sdvice would be greatly appreciated

 

[Cummins12V98]

I would say you are lucky this happened before 100K. Sounds like you will end up with a new trans.

 

[transe]

Sounds like you have a clutch that's got very limited capacity. So a few questions:
(1) When it goes into limp-in, does it launch (from a stop) in 1st gear, then shift directly to 4th, or does it just stay in 4th gear all the time?
(2) If you start it up fresh, shift to Drive, tap the ERS "-" button to put it in "1", take off, and then manually tap it up one gear at a time (when you get up to a speed where it should shift into the next gear), at what point does it slip? When you go into "2", or "3", or "4"?
(3) Do you have any idea which fault codes you have set?

 

[MarkP]

The transmission problem never causes it to reduce speed or power It only locks in 4th when slowing down after you have reached highway speed. nothing is really noticeable other than the 4 shows up on the dash and you cant hardly take off again..I forgot which codes other than something like wrong gear selection for speed..sorry had them wrote down and then cleared all the codes one day and thought everything was back too normal and threw away my list. Let me add something else, when this problem first popped up i had the service light on for a couple of days and had already ordered a new o2 sensor...I got the sensor and went to replace it and noticed the wires at the first sensor were broken on the truck side of the senor. So then I ordered the wiring harness splice and performed the repair. With that issue the pedal would go dead and would have to restart regularly to get power to the pedal again. So after o2 sensor wiring harness repair I cleared the codes, wrote them down and proceeded to drive it but didnt pull anything so the service light didnt come on for several days after that, i thought it was fixed. At that point I dint realize I still had the problem with the transmission, now and i suspect even then I can constantly reproduce the light and the slipping by just flooring it or hook onto something heavy. I havnt been driving it for several weeks...waiting on parts. I will drive it and pay more attention and get my buddy who is a gm mechanic to pull the codes again. I am thinking that it wont really rev up between shifts without a heavy load. one other thing, it hangs up big time at the 1-2 shift when you mat it, even empty. Sorry for the rambling thanks for your input TransEngineer.

 

[transe]

Yes, get the fault code(s) from it. Usually, full limp-in (4th gear only) is due to an electrical issue rather than a slipping clutch. But the codes will tell for sure why it is going into limp-in, and where to look to find the real problem.