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 Sunday at 03:34 PM1 day 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

ATF+4 is typically used with factory transmissions for the fact it has a lot of friction modifier which makes the clutches and bands slip for the soft shifts. Dextron/Mercon typically does not have the heavy amount of friction modifier so there is a sudden grab of clutches. Stalling issues till the ATF thins out some.

Manual Transmission Tidbit...

Here is what I know even manuals. Since I went up in power (500 HP) I wanted better cling to the gears so went from 75W-80 to 50 SAE which is actually 90wt gear lube. It stopped wear on hard facing of the gears.

So in your case you need to find a fluid that keeps up in high temperature (protecting clutches and gears) then to have cold weather characteristics that flow good to prevent stalling. Brands and different blends of friction modifier might help. That's the tough part enough slip not to stall but sticky enough not burn bands and clutches.

Edited 15 hours ago15 hr by Mopar1973Man

That’s all some serious food for thought!

I currently have O’Reilly Conventional Premium ATF Dexron III in there.

Firepunk was very specific about it having to be conventional dex3 fluid.

If you have a suggestion for other oil, I am all ears/eyeballs.

7 minutes ago, Snoxxy said:

Firepunk was very specific about it having to be conventional dex3 fluid.

Just a quick search on Google AI turned up...

Dexron-III automatic transmission fluid (ATF) has a higher kinematic viscosity (approx. 7.0-7.5 cSt at 100°C) compared to modern, thinner fluids like Dexron-VI (approx. 6 cSt), making it a suitable choice for older, heavier-duty, or high-mileage transmissions requiring thicker fluid to maintain pressure and protect parts. 

There is your thicker fluid that needs a bit more time to warm up in cold climate.

Viscosity Profile: Traditional Dexron III/Mercon fluids offer a thicker, more viscous, and stable oil film compared to newer, low-viscosity, fuel-efficient fluids.

Might look at the specifications sheets of different fluids and them figure out which fluid is better based on "kinematic viscosity" scores.

Well dang!

You are taking me to school here!

I did some quick searching/google/bing and even asked Jeeves :) and turns out that valvoline dex3 is likely the best cold weather performing fluid out there. cSt of valvoline is 2 points lower at 40C compared to competitors. However, the Brookfield test is checking for cold weather performance, and valvoline has the lowest pour point and the lowest cP at -40C.

Guess I am going to change fluids over and see how that does.

Your subscription is worth it, right? 😁

Good, at least you have the knowledge to do a scientific study to figure out what your transmission is like for fluids. Remember, this is a temporary weather issue, but you can make a better choice of fluids for your transmission. When we modify these trucks for more power, more torque, more towing abilities, there is going to be a forced change of fluids that fit the new design.

Like my example of the manual transmission, I was seeing extremely high transmission temperatures on 75w-80 SynTorq Fluid back in the day, this became to thin and cause my damages. Now with thicker fluid to cling to the gear and not easily spun off the gearface so there is something between the gear face protecting the gears from touching. This is a known issue for G56 (manual 6 spd) for using ATF+4 in my 2006 G56 transmission. Yeah, that will be another fluid I'll even change and upgrade too. Again, I've increased power on Thor, and you need better protection or the transmission will wear!

Point I'm making once you leave the stock power realm start researching your lubricants. Don't just settle for Redline or AMSOil synthetic because of the brand name. Also look at the temperatures you operate at what is your power increase over stock. Just consider true 1/4 mile trucks don't run just 80w-90 in the axles because its too thin. I've seen some professional trucks running 250 wt in the axles. Just consider factory 85w-140 for limited slip axles factory setup. Again needs friction modifier too. Keep the axle clutches from ratcheting.

On 2/8/2026 at 9:50 AM, Tractorman said:

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

You are right about this being real too. There was a flash update for the PCM to correct for this in stock form for the most part. I'm missing that TSB from the article database and will have to hunt it down.

His I think is a bit deeper issue with viscosity being more the issue.

2 hours ago, Mopar1973Man said:

Your subscription is worth it, right? 😁

Point I'm making once you leave the stock power realm start researching your lubricants. Don't just settle for Redline or AMSOil synthetic because of the brand name. Also look at the temperatures you operate at what is your power increase over stock. Just consider true 1/4 mile trucks don't run just 80w-90 in the axles because its too thin. I've seen some professional trucks running 250 wt in the axles. Just consider factory 85w-140 for limited slip axles factory setup. Again needs friction modifier too. Keep the axle clutches from ratcheting.

This is pretty accurate.

One of my other cars is an Evo with a stroker engine that was built when I was still stationed in Japan. The builder told me that with the clearances, i need to run 20w50 oil, and that my minimum hot oil idle pressure is 15psi ( factory engine minimum oil press is like 5psi, gas engines are a wee bit different).

The builder had used Motul engine oil, but that stuff was CRAZY expensive in Japan.

I used LiquiMoly, hot idle pressure dropped by a few psi, still above the minimum, but it dropped.

Then I tried ELF racing oil, and that could barely hold minimum psi, car ran noticably rougher.

Enter Valvoline VR1. That stuff is AWESOME. I do not know what valvoline puts in there, but its amazing! super resilient against breaking down, holds hot oil pressure even better than Motul. And it is very reasonably priced.

Mind you, this poor car gets hammered and abused every single time I drive it. It really brings out the pissed off teenager in me.

Lesson here, all these oils were 20w50, and while in theory they should all perform somewhat similar, this couldn't be further from the truth! And now I have a case of VR1 on the shelf at all times.

Also, I checked the AMSOil dex 3, and its cold pour point and cold flow performance are FAR superior, but it is synthetic of course. research will continue.

Love it. You are going to find the answer now that you have a nose for what you are looking for!