So, I'm driving along on cruise control at 100 kmh on the highway and bang! Engine winds up to 7000 rpms and the truck is suddenly on a steady decent stuck in 2nd gear.

Pulled over to see a P1744 code. Needless to say it scared the piss out of me that it would happen on high speed, placing the truck into a limp mode. It was dark, side of the road...I was in a panic and had my OBD2 on me and reset the code to see if it was a blip. Got back on the road, and it kicked on again after a few kms.

Normally I would give up, but I decided to reset it once more, and was able to drive home for another for another 80 km with no issues. Thank goodness.

Today it kicked on, on my way back from COSTCO gas going up a hill around 50.

I'm about to take out the TCM, but have a question.

Why would the low coast kick error kick on at high speeds? I thought the gears of the transmission would just blow up. I'm certain that I would have been in a higher gear than 2nd (perhaps 4 or 5) on the highway, and thought that code would only occur in 1st or 2nd gear deceleration.

I just saw another contributor with a similar problem a week ago, ironically.

Looking at the service manual, there appears to be a method to test and produce that code (P1744) by duplicating a certain driving condition in 1st and 2nd gear.

Need some confidence of what to to check first and how.
I'm assuming no power or grounding issue with the TCM or I would be thrown more than one code?
Take the TCM out and look for the obvious pins?
What the heck is the AT SW2? All I see is a temperature sensor being replaced in the diagnosis lines in the manual.

The Service Manual Points to these as culprits:
● Harness or connectors
(The solenoid and switch circuits are open or shorted.)
● Low coast brake solenoid valve
● ATF pressure switch 2



Thanks everyone for any help.

I think that was me? Had the TCM out and soldered a metal track back together. Different codes though (P1757 front brake solenoid). The intermittent nature of your issue may point to a broken contact? If you have the means to drop the transmission pan it's pretty easy to check.

Not an expert, just got lucky.

Thank you.

I'll be dropping it this morning and hope to find something obvious (pins or contacts are broken) and put humpty dumpty back together.

I've ordered in a solenoid kit for this as a backup, in case it is the low coast solenoid that's gone bad.
Based on some forum information, mine is a high ohm version in the 2005 V6.

Any updates? Hoping "no news is good news"...

Well I'm dropping the pan this weekend, no time this week. I've been driving carefully on city roads all week and no issues...until today.

So, I have had the code 1774 pop up again just on my way home. !st time it happened since Saturday.
I literally moved from a stop to 2 km/h and the code popped up in a parking garage. So frustrating.

I've armed myself with a new crush washer, a case of ATF fluid, a soldering iron, and a ATF filter kit to do the job. I've also received a reman-solenoid kit and will replace them. They are all Made in Germany parts - look good. We will see...

Saturday will be the day. I hope to find something obvious and wipe my brow.

edit: I found what ATF Pressure SW 2 is - it's the solenoid itself? I found the reference inside of the flow chart under A/T Control system of the manual under "outputs".