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Discussion Starter · #1 ·
Just finished installing my Breakaway torque converter on my 2010 dodge ram 1500 4.7L with a 545 RFE trans. works beautifully accept the transition from 2 gear to 3 gear, the rpm's do not drop down low enough. When i am on the highway going about 65-70 mph my RPM'S are pretty high. sitting at 2,200rpm compared to the 1700 rpm's i was getting with my stock converter. I was just wanting answers to that. It just doesnt seem right. Theres something going on between 2nd and 3rd gear. What do you all think i should do about it? I have a diablo trinity tuner. Maybe a reprogramming or a special tune? or is it something with the transmission itself
 

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At 65-70 mph I'd expect you to be in lockup (TCC engaged), so the converter stall speed, etc. shouldn't make any difference.

You're only in 3rd gear at 65-70 mph? Why not 4th or 5th gear? The trans only does what the PCM tells it to do, so I suspect your Diablo "tuner" may be the cause (although I'm unfamiliar with all the aftermarket tuners, so I don't know for sure just what they affect).
 

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Discussion Starter · #3 ·
No im sorry for the misunderstanding, no when im traveling 70mph its in 5th, but when its picking up speed to 5th gear the transition from 2nd to 3rd is what seems odd. The transition is not happening at 70 mph.
 

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Discussion Starter · #4 ·
Yes i thought it should lock up at that speed but it doesn't seem able to.rpms remain high
 

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Don't know quite what to tell you. I don't know how your tuner is affecting things. You could drive it with a dealer tech (with a scan tool). They could then monitor your gear and TCC state to see what's going on. TCC should be able to lockup at high speeds with no problem. If that's not happening, then the first question is: Is the PCM actually commanding the TCC to lockup or not? If not, then it's a PCM / tuner issue, not a trans problem.

As far as the 2-3 shift, again check it with a scan tool to confirm it's really a 2-3 shift you're feeling, and then check the level of converter slip before and after the shift. It may be you just have a lot more converter slip (in 3rd) than you used to (due to your new converter), giving you higher-than-normal engine speed. If the trans was slipping, it should set a fault code.
 

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Discussion Starter · #6 ·
I forgot to mention. When im going 65 mph the engine will sit at around 2000 rpms, but then every now and then the rpms will drop to about 1700 for about 3 seconds. Then the check engine light turns on and the rpms shoot back up to 2000 rpms

Trouble code:

P0740

TORQUE CONVERTER CLUTCH SOLENIOD CIRCUIT/ OPEN
 

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Discussion Starter · #7 ·
Ill look into contacting a dealer tech with a scan tool. By the way I appreciate the time your taking to help me out. Learning some new things
 

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I forgot to mention. When im going 65 mph the engine will sit at around 2000 rpms, but then every now and then the rpms will drop to about 1700 for about 3 seconds. Then the check engine light turns on and the rpms shoot back up to 2000 rpms

Trouble code:

P0740

TORQUE CONVERTER CLUTCH SOLENIOD CIRCUIT/ OPEN
Well, yes, that is an important piece of information!

P0740 means the PCM commanded full TCC engagement (zero slip), but the TCC was not able to actually achieve it, even at max duty cycle on the TCC control solenoid. This indicates a problem in one of the following:
  • Torque converter (internal)
  • TCC control solenoid
  • TCC control solenoid wiring
  • TCC control valves (in the pump)
Usually, if the solenoid or wiring is bad, you will also get other faults (for the solenoid circuit being open, etc.). So I doubt that's your problem. If you just replaced the converter, maybe your new one is bad. Or, did you replace it for this same problem (P0740)? If so, maybe you have a sticky control valve in the pump (so replacing the converter didn't fix it).
 

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Discussion Starter · #9 ·
The reason for the installation of the new converter was for a higher stall speed for racing. The code began happening after we installed the aftermarket torque converter from TCI part number 141600. My stall is at 2500 now compared to the 1500 with the stock converter. Worked completely fine with the stock converter of course. Now this issue is coming up. My thoughts were that it may have something to do with the trucks computer. Since i also have a Diablo Trinity Programmer installed also.
 

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P0740 means that the PCM is cranking the TCC control solenoid up to its max possible pressure, but the TCC still cannot achieve full lockup (zero slip). So your engine torque is exceeding the capacity of your TCC. I can't tell you whether that's because the engine torque is too high (due to your Diablo programmer - I have no idea what it does) or the TCC in your new converter is too weak.

Look at the driver's side of your trans bellhousing, just below the upper cooler line. Do you have two small pipe plugs there? If so, you can connect a mechanical pressure gauge (to these taps) to confirm what your TCC apply pressure is running. The upper front plug is TCC release pressure. The lower rear plug is TCC apply pressure. When you're in TCC mode, release pressure should be near zero. Apply pressure (in full lockup) should be close to line pressure (100-120 psi at heavy throttle would be my guess). If your apply pressure is OK but you still get a P0740, then either your engine is too strong, or your converter (TCC) is too weak.
 

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Discussion Starter · #11 ·
I believe i discovered the plug. Now have to look into the mechanical gauge. I'll do some research to find out. Also i will try to find the specs for what the tuner actually does. Let me ask you this though. If this continues, will my transmission or anything else suffer a catastrophic failure?
 

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I believe i discovered the plug. Now have to look into the mechanical gauge. I'll do some research to find out. Also i will try to find the specs for what the tuner actually does. Let me ask you this though. If this continues, will my transmission or anything else suffer a catastrophic failure?
Not a catastrophic failure - more like a slow death....

When you set a P0740 fault, the PCM disables TCC engagement. That means your TCC never locks up at all. That means you are generating extra heat inside the converter much of the time (whenever it would normally be locked up). That means that, on an extended drive, it gets very easy to overheat the transmission. Trans life goes down as temp goes up, so while this will not cause an immediate failure, it will definitely hasten your transmission's demise.

So for normal, short trips around town, no problem. You will lose fuel economy (due to no TCC) but you won't really damage anything. But long road trips would be unhealthy for your trans. And please don't do any towing (or run on steep grades) if you can avoid it. Those will cook your trans pretty quick if you can't lock the TCC to help cool things off. Again, when I say "cook your trans" I don't mean sudden failure - but your trans may only last, say 50K miles instead of 150K.

So bottom line: This is not something that absolutely must be fixed immediately, but you definitely want to get it corrected within the next few months if you can.
 

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Being that it happened with the new TC install, it is almost certainly the TC. Do you know if that TC is a stock converter that is modified? Many times the "cheaper" aftermarket converters are cheaper for a reason, and the clutch can't handle the torque from the engine. I just googled that converter and it seems pretty inexpensive so I would bet that the clutch is simply not enough to handle the torque from the engine, especially with mods(the tuner probably adds around 60 lb ft of torque max, and 30 lb ft peak). Often times too they use a converter of smaller diameter to get a higher stall (like one from a car) and modify it to fit. The problem here is you drastically reduce clutch surface area...

I would pull the converter out and stick the stock one back in (or another like a billet aftermarket one), change the fluid (due to the reasons TE described above about heat and trans life and fluid life). Spend another $150-200 now and save thousands later...JMO.
 

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Discussion Starter · #14 ·
Thanks Sean, so basically it isnt worth it at the end. I guess i am stuck on the power it delivers compared to the stock. So ok, i was thinking that TCI was a pretty reliable brand. Its just such a hassle dropping that trans. I wanted to be sure that it wasn't going to work. So i should just try selling the TCI converter?
 

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Being that it happened with the new TC install, it is almost certainly the TC. Do you know if that TC is a stock converter that is modified? Many times the "cheaper" aftermarket converters are cheaper for a reason, and the clutch can't handle the torque from the engine. I just googled that converter and it seems pretty inexpensive so I would bet that the clutch is simply not enough to handle the torque from the engine, especially with mods(the tuner probably adds around 60 lb ft of torque max, and 30 lb ft peak). Often times too they use a converter of smaller diameter to get a higher stall (like one from a car) and modify it to fit. The problem here is you drastically reduce clutch surface area...

I would pull the converter out and stick the stock one back in (or another like a billet aftermarket one), change the fluid (due to the reasons TE described above about heat and trans life and fluid life). Spend another $150-200 now and save thousands later...JMO.
Sean,

Good point! Being "production minded" I hadn't considered the fact that this new converter is likely a smaller diameter. The TCC capacity is directly related to the disc diameter, so unless they're using a double-sided disc (or multi-disc) TCC, a smaller converter will have significantly less capacity.

Maybe the name "Breakaway" is a reference to what happens when you open the throttle with the TCC engaged....
 

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Thanks Sean, so basically it isnt worth it at the end. I guess i am stuck on the power it delivers compared to the stock. So ok, i was thinking that TCI was a pretty reliable brand. Its just such a hassle dropping that trans. I wanted to be sure that it wasn't going to work. So i should just try selling the TCI converter?
Well, TCI can be a good brand....but just like a lot of times there are good products and bad products from the same manufacturer. I just made a quick judgement on your converter based on the first price tag I saw on google.... post the specifics on your converter and I'll look at it at home tonight and see if it is in fact what I'm thinking...
 

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Maybe the name "Breakaway" is a reference to what happens when you open the throttle with the TCC engaged....
And sorry to laugh at your pain, but this comment was funny!

Also, to rule one more thing out, you should tune the truck back to 100% stock and see if it still has the issue. That will at least rule out the programmer.
 

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Discussion Starter · #18 ·

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Where would i go to get my computer reprogrammed to complete stock?
Maybe I misread but I thought you had a diablo predator? You can do it yourself if you do... I'll look at that link this evening.
 

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Discussion Starter · #20 ·
Its a single disc converter. Just spoke to a guy from TCI. He said that it should handle the horsepower with no problem. I have a feeling though he wasn't to educated on the problem.
 
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