heres some info about the car:
175k miles. i changed the trans fluid 2 years ago with fresh fluid and filter and made certain to slightly overfill to hopefully ensure the shift solenoid's submerged. fast forward to today, noticed when i was out doing soem tuning that the car felt like it was not shifting from 2nd to 3rd at the proper shift point and that when i slightly applied throttle to unlock the tc and downshift it didnt 'feel' right. i pulled into a random hotel and checked my tune and did a quick reflash. when i put the car into reverse the car moved less than a centimeter but then stopped. i revved a bit more and the car wouldnt budge. i put it in drive and the car slightly moved forward without throttle. i was able to put the trans into neutral and pushed the car out of the parking spot and put it in drive. car does move forward but needed more throttle to get it going. i logged a scan and noticed theres zero line pressure and that the car shows in the vcm scanner of going from 1st to 4th but i dont feel the car shifting and just one gear going from 0-50mph. i do feel the converter lock though. there are no DTC codes. so is this the infamous shift solenoid or something broke in the trans due to the harsher tune i have setup for it? i was able to baby it home and park the car for now.

 

Might want to check the fluid level again.

 

Sure thing. I'll have to find the time to do that and it's been getting colder here in pa. If it's low on fluid, 1) where did it go? I didn't see any external leaks, 2) would low fluid cause loss of no line pressure?

 

Have you tried reverting to the original tune? Did you formerly get a pressure reading? I'm not sure that is an active PID.

 

Donbrew, yes, that was first thing I did was revert back to stock tune and that's where it's currently at but no change.
in the past logs before today, I'd get line pressure psi reading in the vcm scanner

 

I drew attention to your words "... and made certain to slightly overfill ...".
The pressure in the automatic transmission is quite serious, therefore, the excess of the transmission fluid level contributes to the squeezing out of rubber parts (gaskets, oil seals, sealing elements inside parts, etc.). If the automatic transmission is new, it successfully resists breakage; if the automatic transmission is worn and has the beginnings of future problems, the increased pressure hits the weak points and breaks the defense. I think that by exceeding the pressure and at the same time applying hard firmware, you unwittingly contributed to the death of some kind of automatic transmission organ. Professional diagnostics will reveal the place where Satan is hiding.

Where can the transmission fluid go? Either outward through the filter cover, or into the radiator through the cooling unit.

 

Agreed, Geg, over filling can be detrimental to the internal seals of the automatic transmission, as can retuning the transmission shift points.
In this case , age of the parts can also cause problems, such as sticking solenoid valves.

Thanks to fastsuv there’s a how to thread

https://www.chevyhhr.net/forums/driv...olenoid-61313/

 

I didn't overfill by alot. For example, if a drop the pan can fill 4.4qts, I filled it to 5qt even, but not like I poured 6qts. Also I had read it was better to slightly overfill to ensure the shift solenoid didn't get enough lube to overheat and fry which I read in some of the other past threads.

 

The fill recommended for the 4T45E fluid type and capacity

Capacity:

Bottom pan removed 7 liters (7.4 quarts)

New converter 2.5 liters (2.6 quarts)

Complete rebuild 10 liters (10.6 quarts)

Type:

Use any Dexron VI fluid

 

Thx old blue, i believe i poured 8qt seeing the drop pan was 7.7qt.