Another toyota truck with P0770 code

seems like this is a common toyota thing. 1998 T100, V6, 4WD, auto trans, 169K miles. Check engine light (CEL) keeps coming on. Code is P0770. My mechanic has flushed the trans; and then replaced the AT selonoid and AT filter. But CEL keeps coming on and off willy nilly, and the truck seems to shift funny when CEL comes on. Its always the same P0770 code. My Brother in Law (a Saab Master Mechanic) sez that the truck is going into a “save itself” mode during these times. The CEL will eventually go off and truck shifts normally again. Sometimes the tachometer “goes crazy and bounces all over” when CEL is on, but not always. My mechanic cannot resolve the code problem yet. What should he look for next? Is it safe to continue to drive truck even though CEL and P0770 keep coming on? Would it be okay to drive the truck 750 miles towing a 1996 Saab 900 to Colorado (home of Brother-in-law Saab Master mechanic)? BTW, the flex plate blew apart about 10 months ago and was replaced.

Thanks.

Kevin in OK

I show that code as “Shift Solenoid E Malfunction”.

The solenoid is internal to the trans. I’m not a tranny guy, but this job needs a tranny shop.

Even without a malfunctioning transmission, I wouldn’t tow a car 750 miles with that truck. IIRC the T100 wasn’t exactly a torque monster. If you plan on putting the Saab on a trailer, there’s a fair chance you’ll be exceeding the towing limiations of the truck.