Greetings,

Long time listener, firl time caller here.

TLDR: When cold, the transmission sometimes stalls the engine, but only once. Trans new - Firepunk, billet torque converter.

EDIT - No Codes present

Video with the issue posted on bottom of this post.

So I recently moved back to the states from a long stint living overseas, and I picked up a 99 4x4 A/T truck. Power wise, the truck is completely stock apart from an Edge EZ the PO installed. Everything was great, except the trans would not lockup in O/D. Following many suggeestions from here that could have an effect on the lockup, I realized this was a torque converter issue.

I ended up deciding to bite the bullet and have a built trans put in, and had Firepunk DIesel install one of their stage 1 transmissions, which comes with a billet single disc torque converter.

The trans works great, OD locks up super hard, have about 3500 miles on it so far, and i have no qualms with how it shifts or how it behaves.

Here is my issue. After christmas, drove to northern Ohio (I currently live in southern GA), and of course it was quite a bit colder. The truck sat overnight and it got pretty cold, as it dropped to roughly 15f. When starting it, I let it run for about 5 minutes, and when pulling it into reverse, the engine stalled out. This was new to me. once putting the truck back into P, and trying again, it worked fine.

This has happened a few times, and I even reached out to firepunk about this, and they thoughts maybe my PCM commands lockup and that this causes the engine to stall out. I made a test circuit that lights up a LED whenever the PCM commands lockup. With this I was able to prove lockup is working as required.

I googled this a bunch, and this is apparently a relatively known issue on VP44 trucks, for the injection pump can't cope fast enough with the added load of the lower stall?

I have since started to raise rpm to about 1000 when putting it into gear, essentially power braking it, and this totally works, but I feel like there should be a better solution.

The stall is also not extremely abrupt, it really feels more like a car that has the emergency brake pulled, and someone releases the clutch while in gear. The engine loads and dies, it happens within about a second.

Further, if the truck happened to stall due to this, once restarted, it powers through it.

I am all ears if the smart folk in here have some insight into this, as the approach of "thats just how a VP44 is" doesn't sit right with me.

Thanks in advance, and sorry for the long post, I try to be descriptive.

Phil

P.S.:

I was unable to attach a video, so I just threw it on youtube as an unlisted video.

Edited 18 hours ago18 hr by Snoxxy
added information - cleaned up formatting

Long posts are appreciated - especially when they are informative - like yours.

I'm leaning toward your new low-stall converter triggering this issue. A stock converter has a stall speed of about 2,100 rpm, so it does not put much of a load on the engine when "drive" or "reverse" is selected. Your new converter probably has a stall speed of around 1,800 rpm, so shifting into gear will load the engine much heavier, especially in cold weather.

I vaguely recall that there was an ECM update (referred to as "Anti-stall") around 1999 for these VP44 trucks. I think it was geared for the manual transmission trucks, but possibly the automatic trucks as well. Maybe @Mopar1973Man will chime in on this topic.

Have you tried taking the Edge EZ completely out of the circuit?

• John

John,

Thanks for the reply!

I have no removed the EZ yet, maybe something to consider. I did ask Firepunk what stall the new TC is, and I was told about 150rpm below factory. I have ZERO issues driving this thing around, it shifts super crisp.

I will look into the this ECM thing some more, another thing I am chasing right now is the Wait To Start delay, it is a couple seconds right now, so from reading through here, I know that I have to look into getting the ECM rebuild/replaced. When this happens, I will be asking about the anti-stall feature.

Phil

I show up... The member who pops up in this type of stalling issue is @pepsi71ocean he had a DTT transmission built and had a similar issue with stalling. It turns out that the torque converter is too low of a stall with the temperatures. If your valve body has the mod done to pump in park, it would help with warming the fluid up, making it a bit thinner before you shift into Drive or Reverse. The problem is that the fluid is thick and cold, and the low stall converters don't do well in cold climates at all. Basically, the best choice is to set the parking brake and put the transmission in Neutral to get the pump flowing. As the pump is flowing, you have the heat exchanger on the passenger side, which should bring warmth to the fluid faster. Give that a shot and see if that helps out.

Thanks for the response!

So I did the Neutral idle for a bit as well when this was actively going on, and I am not sure if this helped or not, as I would let the truck idle for about 3 to 5 minutes and then put it in gear. It didn't stall very often to begin with, but I never had it stall doing the neutral idle.

I really only had it stall maybe a total of 5 times over a few weeks before I employed the "raise the RPM while standing on the brakes" method, which has been flawless so far.

I will keep monitoring, but here in south GA I doubt we will have any more really cold mornings happen, and perhaps TC will loosen up a bit over the year.

Is there perhaps better fluid that will be better in the cold? Firepunk did specify DexMerc 3 NON synthetic, so there is a specific suggestion for a brand of fluid that deals better with the cold, I am all ears.

Phil