It may hold up in a truck that doesn't get used as a truck. When I pull trailers, I tip the scales between 16,000 and 22,000lbs. I do this regularly. 5,000 miles every 3-4 weeks. This truck doesn't just bring trash to the dump or groceries home, and it doesn't play with imports at the stop light. It doesn't tow a landscape trailer or a little toy fishing boat. It pulls skidsteers and excavators, pallets of block, brick, and steel.
The four month tranny was built by TransAxle, a primary supplier for CDL level units. We've been running their transmissions in our fleet trucks for nearly a decade with next to no issues; and by next to, I mean mine. I got 177,000 miles out of the original (un-modied) transmission doing this exact same job, and it only blew because our mechanic got the brilliant idea to install different cooler on it that had a faulty check valve which melted it down on it's maiden voyage. #2 was a faulty Chrysler unit that blew in the first snow storm. #3 was it's warranty replacement, which went 100,000 miles before the TC came apart. 100,000 miles on a stock transmission, plowing snow all winter and pulling 5-7 tons all year, with intake/exhaust and plate full forward. I know how to drive, or it wouldn't have. Chrysler transmissions are just ****, and $700 in parts is not enough to make a reliable workhorse out of them with 4-500HP pumping through it. I'm sorry, it's just not the case. It may be enough for responsibly spirited Joe Homeowner, but put that much muscle into a real work truck on a daily basis and the weakest link will grenade.

 

170k on a stock trans with an engine that isnt stock speaks for itself. i have no more arguing to do. if installed properly with a better converter and better hydrolics (holding the clutches from slipping) these trannys are just fine.

 

170K was with a stock engine, trying desperately do this job without destroying the poor truck. #3 was a stock 47RE and had considerably more beef in front of it though, and that's how long I milked it. #4, my $3500 transmission, was not a bad unit. It probably would have lasted forever if it wasn't in a real work truck, and it definitely would have lasted forever bolted to a stock 12V.
That being said, a little bit of common sense goes a long way, but you need more than a little common sense to keep a Chrysler tranny together whether it's stock or not if you're actually working it. You'd like to think that a transmission rated for 450HP would be ok in a truck that isn't making 300, and depending on what you do with your 300HP, you might be right. But if you think it's safely over-built for that 300HP and regularly go easing it to the floor on the highway with 1500lbs. in the bed just trying to maintain the speed limit on hills, know that it's days are numbered. If you regularly do it with a trailer weighing twice what the truck does, those numbers are countable on fingers and toes. The upgraded TC may take it, and the upgraded VB may help- but the day is coming when you'll find that you have 1st, 2nd and Park, and a chocolate milkshake in the pan. That's if you get lucky, and your beefed up TC and VB don't take your 4-500HP and exterminate the input shaft with it.
For most people it may take years, or even never; but my mileage schedule promotes a vastly accelerated time table for seeing what works and what doesn't. I live in my truck, so it's my baby. That loving care is the only reason it's lasted a decade and a half pushing blizzards and pulling machinery and still looks and feels like new- but it does have a job to do 50+ hours a week and I expect it to do it, and then be my weekend warrior too. It's more than most people will ever ask of one of these old rigs, but the few who do have found the same thing I have: you can dress the tranny up real pretty, but it will never have the potential to withstand what a 12V has the potential to hit it with unless you treat it like it's made of glass. Which, actually, isn't an unfair analogy.

 

If you work your Cumins that hard ... Get an Allison HT540 and you will never have to do it again .... and it should be around 3500 as well...

I have seen these in box trucks with a 3126 cat banging out 350hp and 1100LB/TQ and never been rebuilt with over 620K on the clock .... manny times i have seen this ... and yes its is how u drive it and how good you built it too ....

I have been searching for a buildable unit my self because my 47rh aint gonna last much longer with how I drive this animal ...

 

Oh man, you have no idea how much I'd love to put an Allison in! The [very limited] research I've done has me understanding that getting an Allison isn't the hard part, so much as making it work in the Dodge. I just didn't have time to get it all worked out before #5 gave me the big FU. I expect #6 to last me a long time though, so hopefully when this one is whipped I'll be ready with the knowledge to make the conversion. I'd like to think that this trans will last forever, but at the rate I'm racking up heavy miles I'm sure another rebuild is inevitable unless I change jobs...

 

well I missed a lot on this conversation...
let me get back to it can someone tell me how to tell the difference between my torque converter failing and my tranny failing? it started slipping again today and I've been pretty much baby it I'm thinking some more metal clogged the filter & my hydraulics stopped workimg like they should