Hows it going guys?

I have a 1997 Ram 2500 with the 5.9 magnum. Originally was only supposed to be my high schooler rig but after i graduated several years ago she became my baby and my project. She runs perfectly fine for a rig thats got 185,000+ on her (then again i maintnace her).

My question today is regarding the troublesome 46re. Ever since i bought the vehicle 4 almost 5 years ago it has been pulling a P0740 code. Ive maintnaced the tranny and found no sighn of a bad solenoid or bad wiring. Seems to shift just fine and no grinding or slipping. I have the carfax report and it says the first owner had a new tourqe converter thrown in, shortly after he got rid of the truck, and the second owners (according to them and if they are telling the truth) say the check engine light has been on since they had it. (I am the third owner)

Im not a tranny guy but from my knowlwedge, if the solenoid had been out for nearly 6 years wouldnt the tranny be toast? Im kinda thinking the tourqe converter that was put into it may be the wrong converter possibly? It seems thats when this problem first originated so is it worth dropping the tranny and checking out the converter, replacing the solenoid or going for the whole nine yards abd replacing both the solenoid and the converter?

Quite frankly the troublesome 46re has me stumped lol

Thanks for all the input guys!

 

P0740 Torque Conv Clutch, No RPM Drop at Lockup

Does the t/c actually lock up? Do you see about a 200 RPM drop when it engages?? If not, real possibility that the replacement converter was a non-lockup type. That would certainly annoy the PCM.

If you have the receipt for that work, or know where it was done, check the part number of the converter, and see if it is/is not lockup.

Welcome to DF!

 

Thats exactly what the code reads.

It locks and doesnt drop(only when shifting of course lol) sadly i dont have the recipt, the tourqe converter was replaced when the first owner had it. I do know where it was done. What surprises me is the mechanic shop that did it is a well prestiged shop in my area and AAA certified so i wonder why they would put that kind of converter in it?

I will definatley be checking that part number and see what it is! Thanks for all your help and welcoming me!

 

Let us know what ya find out.

What's the RPM drop when it supposedly locks??

 

Depends on my speed. At 35mph it locks up at 1200 rpm at 55 to 60 is about 1500 to 1750 rpm. When i let off the gss and let it cost it will normally hold at 1,000 if not slightly higher

 

Wonder if the new torque converter just has a lower stall speed than stock, so, you don't get as much of an RPM drop at tcc engage...... that would annoy the PCM.

 

It might be but im not sure, ive always wondered though cause the idle (in my opinion) is a little low at 750 in park. I know the first owner used her as fifth wheel hauler so maybe he got that converter set that way for a reason? All speculation until i get it taken apart and see what the heck they installed in it

 

No matter the stall speed the impeller will always overrun the turbine by a couple hundred RPM when the converter is in lockup (and by more when it's not). Referring to the converter's impeller/turbine lockup, that is, not the torque converter clutch engagement. Ya wouldn't need a clutch at all if you could get 1:1 across a fluid coupled torque converter.

This thread reads so far like the two of you are speaking different languages.

No, not at all. The torque converter clutch is there to increase fuel economy -- the parts of the transmission behind it that aren't involved in applying that clutch neither know nor care if the thing is present, let alone engaged. They'll run cooler with the clutch engaged/without the friction inside the converter heating the oil, but that's just a happy side effect.

It'd be more economical to troubleshoot the thing than to shotgun parts, but shotgunning works reliably if you get everything that can be involved and don't get any dud new parts.

 

Thanks for the info man. And yeah we are probly on two different pages. Like i said im not much of a tranny guy (especially automatic transmissions), and obviously i have no clue and am asking for info haha. I will probly troubleshoot and start with the tourque converter and see what the part number is as Hey You suggested.

 

While it's entirely possible that you've got a non-clutched converter or a converter with a failed clutch, it's also possible that something else is behind it. You've got some wiring, the solenoid you were asking about, and a few valves in the valve body all involved in engaging that clutch. The easiest thing to test is the presence or absence of the signal that drives the solenoid -- you don't even have to drop the pan to get to the exposed cable. Seems a good place to start, and a broken wire is the cheapest and easiest fix so you'll want to either find it or rule it out before expending the effort and cash to go deeper. Just a thot.