A full flush should reduce those symptoms a lot.

 

Well, I changed the pan/filter/fluid out yesterday. It hadn't been done in quite some time, as the date on the old pan was from more than 10 years ago. Considering the age, there was remarkably little clutch material on the magnets indicating that the clutches are in amazing condition for their age, probaby due to the fact that most of the 300K miles are interstate miles. I am leaning further toward an electronic issue or an issue confined to the torque converter now that I'm satisfied that the transmission is in good condition. Any suggestions?

 

Yep. refer to posting number 2. If you want to drop some coin on fixing a 300k trans it's most likely the solenoids. Dont know if whatever your trans guy "hooked up" to your truck showed solenoid amperage while shifting. The converter lockup is also controlled by a solenoid on the valve body. Get a GAP ITD tool and diagnose it. No one is going to be able to guess what is wrong with your transmission.

 

It did in fact show solenoid amperage. Everything looked solid. I don't expect anyone to guess, I was simply hoping someone in their years of experience may have encountered similar circumstances as I have.

As for the GAP IID, if you show me where I can get one for less than an arm and a leg I'd be happy to purchase one, but unless the problem continues to persist in the next few weeks I will be perfectly happy to continue borrowing my friends diagnostic equipment from his shop.

 

...but if you think $400-500 for a tool as vital as the IIDTool is an arm and a leg, you should probably sell your LR3 and buy a Toyota.

It pays for itself.

 

It certainly is when the other option is free. Not to be blunt but it would probably take significantly less effort and be far more rewarding if you bought a Toyota and sought out to annoy the people at Toyota Nation.

On a more serious note I am aware of the value of the IIDTool and it is on the list of things that I need to purchase, although it isn't #1 and will not be unless my problem continues to confound me.

 

If I'm not mistaken, there's not really any way you can overfill the ZF 6HP26 transmission if filling from the fill plug. You can definitely underfill it, if you don't do it while the car is running, or not up to temperature, or don't cycle the shifter and then re-add fluid, but as far as I'm concerned, unless you somehow plug the hole while adding fluid and then VERY quickly shove the plug back in, all while the truck is running, right next to a blazing hot catalytic converter, there isn't any way to overfill it...

 

That **** was funny.

 

Hmm


The way I understood it: if you fill running/shifting - but too cold - then plug it
The next time you reach normal operating temps (driving), the level would be too high - because the fluid expands with heat

¯\_(ツ)_/¯

 

Ah. You're correct, my mistake.