96 EB 4x4 4R55E shift solenoids

[ThreeJs]

I've been getting an intermittent P0731 code on my 96 EB 4.0 4x4.
Had trans rebuilt about 2 years ago. Re-used the the original valve body and solenoids except for the EPC solenoid. I had replaced that one prior to the rebuild.
Problem seems to mostly occur when outside temps are 100+ degrees in stop and go traffic..
Seems like the trans doesn't downshift all the way down to first. When taking off from a stop it feels like the trans is in the wrong gear or is slipping. If I manually shift out of D into 2 then back to Drive it seems to correct itself but I may get a P0731, Gear 1 incorrect ratio.
If I stop. turn off and restart the problem most times goes away.
I plan on servicing the trans with a fluid/filter change and want to replace the shift solenoids at the same time since the pan is down. Can all 4 shift solenoids be replaced while the VB is still in place?

 

[transman304]

Did you replace torque converter with a reman at rebuild?

 

[ThreeJs]

Did you replace torque converter with a reman at rebuild?

Yes the converter was replaced

 

[ThreeJs]

Alrighty..revisiting this same problem now that summer is here again and temps are near 110 or above. I have been lazy in the cooler months and hadn't replaced any shift solenoids since the trans has been shifting fine. I know, I know..I heard it from the wife already.

Trans 4R55E. Seems to be a solenoid issue. I can manually shift from D1 to D2 then to Drive and it drives fine.

Rather than just replace a solenoid I am looking to replace the complete valve body with new solenoids already installed

Is the a better place that is recommended that updates/mods the valve body for better performance.

Seems I can find complete remaned valve bodies on ebay. Are there there better options?
$145.00 Warranty: Lifetime Core Charge: No

http://www.ebay.com/itm/5R55E-4R44E-4R55E-Valve-Body-Factory-Updated-95up-Mazda-B-Series-Pickup/253020592562?ssPageName=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

Sonnex V/B:
$473.64 Warranty: Lifetime Core Charge: $40.00

http://www.ebay.com/itm/Ford-4R55E-...ash=item43d0721a4c:g:0doAAOSw3YNXbISt&vxp=mtr

Is something like the Sonnex really that much different? At $500 total that is half what I paid for the rebuild of my trans.....