Torque Converter Blackmagic "is it stalling me out"

[Bobzilla]

@Bobzilla are you familiar with how the ecu disengages lock up on a 46RH when braking?

I am more familiar with RE models as well, and there is a stop lamp switch input to the PCM that will disengage lockup as soon as you step on the brake pedal enough for the input, and it will stay disengaged the entire time the brake pedal is pressed throughout the stop. It will ignore TPS input while brake is applied, or to say it will use brake input first.

The RH does have the stop lamp switch input to PCM as well. I have a 93 truck manual but it may not be here with me. I cannot find it.

 

[autopar3000]

I can confirm Bobzilla's comments about the brake switch disengaging lockup in OBD1 trucks. Lifting off the throttle will do it too, as well as any time you press the OD button to turn off or turn on OD (but that's just because it doesn't want to shift into or out of OD with the converter locked).

At first I was thinking the brake switch connection is not 100% required for lockup to work because after I did my Magnum EFI swap I didn't have it wired to the PCM. But the more I think about it I'm starting to believe I might be confusing the period of time when I was running the factory EFI with a 904, because now I remember seeing posts from guys doing Magnum EFI swaps that had to connect the brake switch to get lockup working.

 

[autopar3000]

Thank you. I can’t check the FSM because i don’t have a copy for an RH controlled truck. If you do can you verify please?

For sure there's no OD or lockup relay on the RH trucks. I went through the 94 FSM with a fine toothed comb when I rewired my car a couple years back. Just to be sure they didn't add one in 95, I just checked the 95 manual:

And this page from the 1995 EWD confirms there's no relay. Kind of crazy, but I guess it works:

I'll check the 96 manual now and let you know what I find.

 

[autopar3000]

Incidentally, I have 94, 95, 96, 98, and 2001 Ram manuals in PDF format. If anybody wants one I'd be happy to make it available, but they're 70 mb - 110 mb, so I would need you to give me a way to send it to you since they're way too big for email.

 

[autopar3000]

From the 1996 FSM. It says the lockup is controlled by the PCM, but doesn't say anything about a relay:

Also from the 96 manual. Interesting it doesn't mention the brake switch as something that determines TCC engagement, but I'm pretty sure that's just an oversight:

Here's something interesting, this bit is part of the section that describes the stall test. Basically telling you to do a brake stand to see where the stall speed is. I never considered the overrunning clutch could be slipping. This is obviously for the RE transmission, but I would imagine the RH would be the same: