Question: Chevy Silverado K2500 6.5L TD 4X4 4L80E Trans Problems: No O/D ?

[bigblazer]

Metal contacts inside.you can poke the wires you need to repair thr holes with some silicone.

[FloridaHorseman]

"Under the diagnostic aids it says: A scan tool reads throttle position in percent. Should read near 0% at idle. % should inc`rease at a steady rate while depressing the throttle.
An open circuit in 416[gray wire,5 volt reference] or 417[dark blue, tps signal] will result in a code 22.
Measure voltage across 417[dark blue] and452[black]while depressing the throttle with engine stopped and ignition on.Display should read from below 1.25 volts at idle to over 4.0volts at wide open throttle. The baro. sensor shares the same 5 volt reference and ground. possible problem in the baro sensor?Engine speed sensor and trans temp sensor also share the same ground.
I have a problem in my 92 in my sig that it doesn't get the throttle signal after startup unless it is above 80F air temp. If I stop the engine and restart it recieves the signal just fine. Too lazy to replace the tps at this point."

Read the entire thread at Gauge block for TPS adjustment ~FH

[darthtater]

Thanks guys I'll look into this sometime this week if I have time throughout the Thanksgiving craziness and let you all know how it goes.

[darthtater]

So I got my little volt meter out and tested it and set it to exactly .5 V at idle and at WOT it is about 4.43 V. Okay so I should assume all is well right? Remember the past post where I has 3 codes? Well I adjusted it and took it down the road and...wow is all I have to say. Lets take it from the top:

Code List:

39-TCC Stuck "OFF"
59-Trasmission Fluid Temp Circuit High
68-Transmission Component Slipping
85-Transmission Gear
86-Transmission Gear Ratio Low
87-Transmission Gear Ratio High

I was seeing red all pissed off I floored it and went down the road. Nothing changed lol just made me feel better . So now I'm thinking it might be the TCM. What is your guy's opinion on this? I think the TCM is seeing the wrong ranged for drive and over drive and when to shift. Any ideas? Thanks as always!

~Tater

[bigblazer]

I did read somewhere the other, someone said they had problems.did you mess with that main plug? I unplugged mine when the truck was off and got about the same codes.just not that tcc off.i dont know why it thru codes if the key was off but it did.

[darthtater]

I am going to buy a TCM and put it in and see if it fixes my problem. Should be here on the 28th or the 29th. I'll let you guys know how it goes.

[FloridaHorseman]

I'm curious about how long between the tranny solenoid replacement and the shifting problems returning. I don't know how effective cleaning the outside of the transmission pass-through plug could be. You really need to get that plug out, inspect the pins and make sure that connection is clean and dry.

Here's hoping the new TCM makes a difference for you. Be careful handling the EPROM when you transfer it from the old TCM. ~FH

[darthtater]

Well it's been about 10-12 years or so but it sat for quite awhile after dad bought his new truck right after the engine had been rebuilt the second time. So I would say maybe 40-50,000 miles or so. And I tried taking the connector off and couldn't get it off. Do you just twist it and pull it off? And I will thanks! Now correct me if I'm wrong but the EPROM chip the blue one that pulls off the circuit board right? Thanks for the help!

[bigblazer]

You have to squeeze the sides if if i remember right.yes that the prom,

[FloridaHorseman]

Originally Posted by darthtater

Well it's been about 10-12 years or so but it sat for quite awhile after dad bought his new truck right after the engine had been rebuilt the second time. So I would say maybe 40-50,000 miles or so. And I tried taking the connector off and couldn't get it off. Do you just twist it and pull it off? And I will thanks! Now correct me if I'm wrong but the EPROM chip the blue one that pulls off the circuit board right? Thanks for the help!

It looks like the pass-thru connector is held in place by a torx screw in the head of the cap. You may have to open the wiring bundle to find it.

I've been doing some reading and discovered an old GM service bulletin that calls for the replacement of 1991-93 4L80e pass-thru connectors due to a problem with leaking fluid into the connector. http://www.utterpower.com/gm_4l80e_t..._connector.htm That may be the crux of your shifting problem if the new TCM makes no difference. If the connector is leaking the entire harness probably should be upgraded.

The fact the solenoids were replaced a decade ago and then sat unused and unlubricated for an extended period of time may contribute to the problem. Internal valve bore tolerances are also extremely sensitive to both wear and foreign material. ~FH