Well? How does the story end? Been readin' for 10 minutes, now I want to know...

 

 

Unfortunately I just couldn't get answers on what more to test so I'm just gonna swap it. I'm at a loss. I'm guessing it's in the valve body but I don't wanna throw anything new in until I have more of a definitive reason

 

hey mark, I was wondering If you maybe had thought of anything over the past year? I know I've surely been stumped. Lol I parked it up until about a week ago and was bound and determined to figure it out.

Pulled everything back apart, rechecked everything... I had come across a newer center support and also installed that. Disassembled, spit shined and double checked every valve and spring in the bodies. I felt they were even better than before.... I felt great about trying this girl out again and what do ya know... same exact deal as before. Zero shifting after 2nd, just a bunch of stumbling and bumbling rpms from the 7.3.

I have zero issue sending you some $$ to spend a little more time with me diagnosing this. I haven't brought it to the shop yet.. still just not pulling that trigger and letting this get the best of me, but even the couple trans builder I've talked to can't exactly think of anything without tearing into it.. so it seems I've got quite the conundrum

 

This might not be relevant, but worth mentioning.
Watch this video on the Exhaust Pressure Sensor. A clogged tube or bad sensor can impact AT shifting.

 

Now that sounds like an engine problem keeping the truck from going fast enough to shift to third.

 

Sorry, I should have mentioned that stumbling and bumbling happens way past the shift point.

adding a test i did yesterday. It looks like everything is atleast being commanded to shift correctly, yes?
https://photos.app.goo.gl/EDSfLtYZHh5F5sPR6

 

Did you ever find out ? Contact me if you can .

 

well, unfortunately I'm not 100% sure what exactly fixed the problem... but I gave it one last ditch effort..

i pulled the trans and went through it again 100% making sure everything was in its place

The biggest thing I noticed is that i dont think i ever got the valve bodies as clean as they should have been.
I ended up finding a cheap dishwasher and started using it with some aluminum safe cleaner. They came out freaking amazing. There were a couple bores with slight stickiness so I made sure to hit them with a nylon brush and carb cleaner. I also upgraded the 2-3 shift valve with a kit from transgo.

The other thing i noticed is that when I rebuilt the trans the first time and installed it, I took the bolt out of the head for the trans dipstick tube. I tightened it back up but apparently not all the way for whatever reason.... on this last install I noticed the loose bolt but I also noticed that bolt has a ground strap underneath of it!! So that ground was definitely loose.

If i had to do it all over again, id make sure the shift solenoids were being commanded correctly with power and ground while test driving. Not just with a scan tool... but with i think its called a breakout box or rig something up to know that part was working correctly. Otherwise drop your valve bodies and make sure they are freaking spotless!!!!

after all that my trans works as it should. Coincidencedentally I just had it towed home two days ago because it puked oil out the front seal so I still need to dig into that.

 

VB work, done properly, takes the longest in my builds too. I use brake cleaner first, Superior's bore tools to deglaze (with ATF as lube), then brake clean again.

Once castings clean, then I start the reassemble process as I clean all the valves and springs going back inside.