No luck with a data logger. I did cycle 12 quarts through the system. It is now nice and red.

Also had a new development. Overdrive did engage this morning, once. Engine temp was only about 140* at the time. Once I got on the interstate and the engine was up to temperature it wouldn't reengage.

 

Did you get the check valve taken care of?

 

Check valve is still on the to do list. It shouldn't stop the OD from engaging at temperature though would it?

 

Yes, if it is plugged up, the trans overheats fairly quickly, and the PCM will disable O/D. It *should* turn on the trans temp light in the dash though..... Does that bulb test when you first start the truck?

 

​​​​​​I wasn't aware I had a trans temp light on the 97.

I drained the fluid using the upper radiator port. Seemed like pretty powerful flow through there

 

Ok, that's where it comes out.... So, you have flow at least.

Any codes yet?

 

Still no codes. I will get a 5 second bump by 250 rpm when I cycle the OD switch now

 

That's TCC.

What RPM are you turning at 60 Mph? What gears/tire size?

 

2500 rpm I believe. And 31s with 3.55

 

Yep, No O/D....

Hhhmmmm.... one would think the PCM would whine about that. Can you see what temp the PCM thinks the trans is?