Did yours flutter in and out of OD by change? I have a bad fan clutch and was on the fwy last weekend and it seemed like mine would jump in and out of OD a LOT. I've decided to fix the fan clutch/heat issue before diving too deep into that symptom.


@OP glad your issue seems to have cleared up at this point. i find it interesting that the deeper pan fixed the issue. Perhaps it was the pick up being jammed too close to the pan to get good flow, but I wonder if the additional fluid of the deeper pan is what's helping keep temps cool.

Maybe someone threw the wrong pan on there before you owned it and "fixed" the problem with that spacer?

 

If you RPM are jumping around by 200 or so, replace the throttle position sensor. Dropping in and out of O/D is a MUCH larger RPM change.

 

Mine was going from around 1700 to 2200. It definitely looked like/sounded like OD in/out. This was also around 65 on the highway, engine temp reading 140ish.

 

Ruh-roh.... That's not a good sign. Are you getting any trans codes??

 

no codes/MIL.

 

Then either the solenoid isn't holding, the t/c is preparing to go belly up, leakage in the valve body, or.... the PCM thinks it should turn off O/D for some strange reason. It may be sensing higher engine load, or getting an odd reading on trans temp, (and probably a host of other possible reasons.....) Can you drive it with a scanner on there, and do some data logging?

 

One thing I noticed is that when I hit the OD button on the shift level it doesn't do anything. I haven't confirmed the OD light works in the dash during bulb check because I honestly haven't paid attention and I don't drive the truck a whole lot. Last weekend was the first "long" drive (about 144 miles round trip) I took with it since buying it, and the first "long" drive on the interstate. I was wondering if the cold Mi weather, coupled with a overly cool cool engine could be causing the trans oil to be too low. I also considered the possibility of the OD button malfunctioning in some fashion causing the PCM/TCM to get intermittent command. Of course I've also considered bigger issues such as what you've listed as well.

I don't have a scanner/data logger, but as you've seen in that scanner thread sticky, I'm actively shopping

I suppose I should have started my own thread on this VS hijacking the OP's. Sorry about that.

 

Ok update on the subject, went up north with the truck 4 hrs away, Trans was fine o/d worked great, but got home and checked the codes and the p1740 code is back on! I have no idea what to look at next other than a new trans, anyone have any insight on what could cause this?

 

Check the connections at the PCM, trace the wiring harness, and make sure the plug isn't frayed at the trans.

 

Already ahead of you, that's why I'm pulling my hair out right now cause I'm just dumb founded scratching my head.