4l80e slipping

[john hill]

I have a 2007 chevy 2500hd classic and had the transmission rebuilt because of slipping issues but it still does the same thing we replaced the converter and all clutches I have replaced the speed sensors and am at a losss

 

[MrMarty51]

Welcome to the forum John.
In a real recent transmission thread.
I explained a friend with His Dodge and Cummins diesel.
Automatic transmission. He had disconnected one battery and protected the cable, got done with His AC repairs, hooks the other battery and problems, several transmission codes. I explained to him about the woes of poor grounds and bad positive connections. He blew me off. Was going to take his truck to SLC to get a remanned installed. Just before loading it onto his trailer to drag it over there from Elko, he decides to call an a friend and excellent mechanic. Running the multimeter through its paces, he finds a bad connection on tje underhood fuse box, and a couple other mysterious loose connections, and, someone had pulled the ABS fuse and give it a toss too.
Check your electrical connections and especially grounds. Bright and shiny is barely clean enough.

 

[john hill]

Welcome to the forum John.
In a real recent transmission thread.
I explained a friend with His Dodge and Cummins diesel.
Automatic transmission. He had disconnected one battery and protected the cable, got done with His AC repairs, hooks the other battery and problems, several transmission codes. I explained to him about the woes of poor grounds and bad positive connections. He blew me off. Was going to take his truck to SLC to get a remanned installed. Just before loading it onto his trailer to drag it over there from Elko, he decides to call an a friend and excellent mechanic. Running the multimeter through its paces, he finds a bad connection on tje underhood fuse box, and a couple other mysterious loose connections, and, someone had pulled the ABS fuse and give it a toss too.
Check your electrical connections and especially grounds. Bright and shiny is barely clean enough.

I'm thinking you might be on to something it just about has to be a ground issue

 

[MrMarty51]

I'm thinking you might be on to something it just about has to be a ground issue

And it is a free checkup too.
Another friend, calls Me from in front of the post office.
My car wont come out of park ?
I ask if there is any unusual lights on on the dash ?
No, why ?
He always packs one of those simple diagnostic code readers.
Told Him never mind, hook Your code reader to it and see if it shows any trouble codes.
OK, nope, no codes. HEY, I can put it into drive now !
Told Him he has a bad ground, for some reason the code reader had completed the ground circuit for that solenoid to disengage the safety pin so it could go into gear.
He took it to a shop, shop took the floor boot and covers apart. Yup, somewhere in the process they found a ground screw that was not screwed down tight.
Old Bob calls me back after He picks up his car. Hey that wasnt so bad, cost me only $50.00 for them to tighten one screw.

 

[jrsavoie]

And it is a free checkup too.
Another friend, calls Me from in front of the post office.
My car wont come out of park ?
I ask if there is any unusual lights on on the dash ?
No, why ?
He always packs one of those simple diagnostic code readers.
Told Him never mind, hook Your code reader to it and see if it shows any trouble codes.
OK, nope, no codes. HEY, I can put it into drive now !
Told Him he has a bad ground, for some reason the code reader had completed the ground circuit for that solenoid to disengage the safety pin so it could go into gear.
He took it to a shop, shop took the floor boot and covers apart. Yup, somewhere in the process they found a ground screw that was not screwed down tight.
Old Bob calls me back after He picks up his car. Hey that wasnt so bad, cost me only $50.00 for them to tighten one screw.

That actually sounds cheap for the job. A lot of shops charge 1 hour minimum

 

[dbrannon79]

have you read any codes on the tranny? how is the slippage felt? it could be a bad ground or connection causing it but there has also been some horror stories on these tranny rebuilds. hoping the shop that did the work will cover warranty and that they did actually rebuild "your" trans and didn't just swap in an exchange one. I would take it back to the shop that did the work and take the tech with you on a drive and show them what it's doing. see what they tell you. let us know too what they say.

 

[john hill]

the code is p0894 and the shop has been great to work with but they don't do automotive electrical

 

[dbrannon79]

P0894 is a generic code for the ECM detecting slippage. you need a scanner that will read live data and watch the data from the speed sensors and the TCC slippage. going for a drive and watching the signals. mainly to eliminate the issue being in the TCC lockup clutches. iirc when the TCC is locked up if you see more than 500 rpm from the TCC slippage when in lockup the issue will be a bad torque converter. these trannys are notorious for having weak torque converters. if you find that is the issue, simply replacing it with a triple disc one might fix the problem. But just a word on it, when the TCC goes, it will glitter bomb the trans with clutch material that can take out the rest of the trans clutch disks especially if it's driven hard or being used to tow. other issues could be faulty speed sensors or the wiring to them from the ECM.

I think both @WarWagon and @Will L. have more experience with this.

 

[Will L.]

Sorry- I am not a tranny guy. Take that in all ways btw.

I understand transmissions enough to get in trouble- there are far better guys than me here for this knowledge.

 

[john hill]

P0894 is a generic code for the ECM detecting slippage. you need a scanner that will read live data and watch the data from the speed sensors and the TCC slippage. going for a drive and watching the signals. mainly to eliminate the issue being in the TCC lockup clutches. iirc when the TCC is locked up if you see more than 500 rpm from the TCC slippage when in lockup the issue will be a bad torque converter. these trannys are notorious for having weak torque converters. if you find that is the issue, simply replacing it with a triple disc one might fix the problem. But just a word on it, when the TCC goes, it will glitter bomb the trans with clutch material that can take out the rest of the trans clutch disks especially if it's driven hard or being used to tow. other issues could be faulty speed sensors or the wiring to them from the ECM.

I think both @WarWagon and @Will L. have more experience with this.

we have put 3 different TC in it all new speed sensor and servos tried cleaning as many grounds as I can find now I just need to find someone smart enough / with a scanner to read everything eles

 

[Husker6.5]

Any decent transmission shop should have the ability to do real-time scanning on a test drive, just make sure they don't use a Snap-On scanner as for some reason they don't like playing with our PCMs and transmissions.

 

[udidwht]

Disconnect the connector on the side of the trans. Do you see red fluid? You shouldn't.