2001 Nissan Maxima Slipping in 3rd gear, P0744

2001 Nissan Maxima Slipping in 3rd gear, P0744
Thank you in advance.
2001 Nissan Maxima
transmission JATCO RE4F04B 4sp Auto
P0744
215K miles.
Engine Runs really good
Transmission : ok in 1, 2, and reverse
4th unsure if it even shifts into it.
3rd is fine as long as you don’t floor it, then it slips into Neutral
if you let off gas it slips right back into gear

ATF Fluid : Valvoline MaxLife Full Synthetic with Lucas

history :
around 202k it was shifting very bad , barely moved, and fluid was black but didn’t smell bad.
so I did a slow ATF flush, via 3x drain and fill with few thousand miles between each
along the way used lucus and Seafoam TransTune.
This made it drivable and the more it was driven the better it got and got better with each drain and fill.

My thoughts are its losing hydraulic pressure on the TCC causing it to slip in and out of gear.
I have heard that the solenoids over time get worn out and need replacement, and cause this symptoms.
but these same symptoms could also be other, more serious things. anyway to differ between them?
I am thinking it needs a new shift solenoid block which includes TCC and all other solenoids
but I am aware of it could also be a warned out clutches.

I am just throwing this out there for the form for their thoughts.
is the transmission toast ?
would a new Shfit solenoid block and filter fix it ?

cost ranges estimate
1) Shift Solenoid block replacement (valve body will need to be removed but transmission can stay in car)
2) replace entire valve body with re-mfg one, that includes the new shift solenoides
3) rebuild transmission
4) replace transmission with used one from junk yard

on 3 & 4 would also include replacement of rear main seal

your thoughts
thanks
Busy Dad Trying to save Son’s first car.

• This topic was modified 3 years, 2 months ago by David Fields. Reason: typeo