[Schurkey]

Originally Posted by hunter4ever12

Gotcha that makes sense...One other question I do have though (because as I said I'm not as familiar with this vehicle as I should be) is; from what I've read, I believe my pickup has a TCM (transmission control module) that is completely separate from the ECM is that correct? And if yes I'm assuming the TCM feeds the ECM data and Ultimately the ECM controls the TCM right?

So if the above is all correct, I could very well have another factor to throw into to the equation, and that factor is the PCM.

I will say this, upon further diagnosis last night I still do not have 4th at all, but I also noticed my kickdown function was not working either. So here is how I noticed that. I'm driving along at roughly 35-40 mph. I push the peddle to WOT, and it doesn't downshift. It stayed in the current gear and did accelerate, but very slowly and sluggish compared to if it would have down shifted.

Now from what I've gathered on my vehicle (because it's a 94) the kickdown function is controlled through the ECM and there is no actual kickdown cable that could be manually adjusted, I'm about 99% sure that info is correct because I do not have a kickdown cable going to my TBI. So if this is correct, the way I look at that is it's another sign pointing to a bad ECM or possibly TCM, would you agree?

Originally Posted by Schurkey

Time to buy a REAL service manual for that truck.

The 4L80E is electronically controlled, but I don't know if it's a stand-alone module or integrated into the same computer that regulates the engine.

Wild Guess: Integrated into the engine computer.