transmission solenoids

[SRehberg]

I'm trying to run down a problem in my trans, and was wondering if anyone has ever measured the resistance of the solenoid coils in the trans ? I wanted to get the trans hot, then unplug the wiring harness at the trans and see if the TC coil is opening up once it gets warmed up, but I don't know what the values of resistance should be. If it's not the solenoid causing my TC problem, all I have left is hydraulic issues which I really don't want to deal with yet.



Thanks for anyones input, these transmissions are the weak link in an otherwise great truck. The trans is a 47RE



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'96 2wd with sick TC 38,000mi. 3,000 since new TC and rebuild.

 

[diesaldual]

not to sure on the values.

What is it that your truck is doing?

I ahve gone thru 3 of those solenoids!! all were diff. problems.

May be able to help give some input.

 

[SRehberg]

diesalduals, thanks for the reply, as this one has me and Dodge guessing.



I have posted a few times before regarding this problem, but have finally narrowed it down to the trans. What happens is this: when the truck is cold, everything shifts/locks up normally, until about 5 miles. Then it starts to act up. If in 3rd gear with OD disengaged, it refuses to lock up the torque converter. If in OD and going down the freeway, stepping on the brake or abruptly decelerating, the TC unlocks then refuses to relock for long periods, if at all. Now the strange part. If this happens, and you pull over to the shoulder, start through the gears again, all is fine, hot or cold. Just don't disengage the TC for any reason, or it's back to not locking up. I have an LED hooked up to the TC circuit which shows when the PCM is calling for lockup, which it does, so that eliminated all the sensors & computer, so the only thing left is the solenoid or something hydraulic. It worked fine until Dodge did a piston seal upgrade on the front clutch; then the trans fried due to an oil starvation, so they got to rebuild it entirely. They say they didn't do it, but it sure worked o. k. before, so now they have no idea what is causing it.



What was yours acting like with the solenoids?



Thanks again, and I am anxious to hear what went on with yours.



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'96 2wd with stubborn TC

 

[inarush76]

solenoid values

I believe the solenoid values are 30 ohms. They will vary a little with temperature. There were some trucks that had leaks at the solenoid to valvebody gaskets that could effect the lockup signal oil from moving the valve. I flat sand this area of valvebody and have had castings that had spots that led me to use two gaskets. Is your trans stock? It would be interesting to see if pressure or flow changes in the cooler lines when your L. E. D. lights up. That would indicate valvebody reaction to the solenoid. It is possible for solenoid to function electrically but not mechanically. An exhaust orifice has to close when the solenoid activates. Just a few ideas. Good luck.



James Northum

DTT dealer/installer/Bill K. approved builder

 

[SRehberg]

Inarush76, thank you for the great information; If I put a pressure guage on the cooler lines, will I see a pressure drop when the TC locks up? Also, you mentioned the TC solenoid can function electrically, but not mechanically, & due to an orfice... . is this on the solenoid, or is it in the valve body that could get plugged up with debris? The reason I ask this, is the trans was torn down the first time for a simple seal replacement on the front drum, but the dealer says my drain back check valve malfunctioned, frying my trans 47miles later. I'm suspicious. There was quite a bit of debris in the pan, both brass and aluminum. The intermediate shaft, and a lot of other parts including the rear clutch, OD etc, had to be replaced. No flushing of anything. (they took air to the lines I found out later... . not much good with oil).

Then it lost a rear thrust bearing, again tearing it down; bottom line, they did it three times before it quit destroying itself. This should give you an idea of their capability, and this is Dodge!

The trans is bone stock except the line pressure is 65lbs at idle.



Now they want to give it another go, but I think I'll check it out for myself, but they should fix it under warranty. So what do you think? I've rebuilt 3 727's some years ago, and it was o. k. , so I would think this isn't that much more difficult.



I really appreciate the info, and sorry for the long reply.



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'96 2wd with hope for the trans

 

[inarush76]

there's hope

The orifice is in the solenoid itself. The solenoid uses a plunger to open and close exhaust, it moves by a magnetic field created by the solenoid coil when energized. If the check valve was plugged, was it replaced? What about the coolers? If there was enough debris to clog the check valve then I would be suspect of the coolers. I have seen coolers that would pass air and even fluid when cold, but when hot would only allow a trickle. With repeated gear train failure I would have this looked at carefully. I remove the check valve on every one I do. In my opinion, it acts as a restriction when it is new. A test you can do yourself is to drive the truck till warm, disconnect rear cooler line, put into jug(gallon),start truck in neutral(parking brake on,wheels blocked!!) and see if at least a quart in 15 seconds flows into jug. This fluid should be warm to hot and should have pressure so be careful. A better way is with a flow meter, but they aren't cheap. It is a good idea to have a buddy help with this. Maybe they should opt for a new unit. Then have it upgraded with DTT and be happy.

Building the front unit is very similar to a 727,with some mods,different clearances,clutch pack set-up, the OD section is not that bad,but there is a spring that has some 800lbs of tension on it you have to be cautious with. Hope this helps.

 

[SRehberg]

transmission solenoid

INARUSH76, the information you have given me gives me both hope and depression. I am thankful for the info as it sounds like it is what could be happening/causing the problem. The reason for the depression is this: when the trans fried itself and decided to eat metal, the new TC I purchased and had installed was put in the first time for the seal replacement. Susposedly the check valve stuck causing the catastrophic failure. The new valve I imagine it was a recepitant of the debris as well as everything else that the fluid came in contact with. The mechanic said there was "very little" in the lines, and nothing above the filter on the valve body. I contended the TC and everything else is exposed to the debris; Dodge, (the mechanic denies this). Anyway, after the 3rd time when the rear thrust bearing ate itself, (and aluminum from who knows where) they susposedly cleaned the lines/coolers with air, not the recommended method.

The mechanic said the TC was free of debris as he couldn't get any out. I don't think you can anyway in my opinion, only by cracking open the TC ? Can the rear piston retainer be installed in a position to block the return line lube oil?



The cooling lines as you described, closing down after warming up, sounds very likely in my case. You mentioned the check valve as being removed; any harm in doing this? I have toyed with the idea of taking it out. The check valve was replaced after the trans seized the first time, so if debris is present, then I imagine this ones days are numbered. I haven't dropped the pan since the last go around, but think I better to see whats in the pan.



Once again, thanks for hanging in there for me, as you seem to be right on target with this one. Sorry again for the long post,

but I really appreciate all the input.



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'96 2wd with hope yet

 

[inarush76]

cooler flow

The aluminum may have come from the output support. The intermediate shaft rides in this support and any reduction in cooler flow puts it at risk. Lube oil for the gear train comes from the return cooler flow. You can remove the ball, spring,and retainer from the fitting in the line or take it to a parts house that makes hydraulic hoses and have one made to replace it. The only thing you may notice is some drainback of the conveter after sitting for a number of hours, just start the truck and allow to idle in neutral for a minute or so and you'll never feel it and it allows the lube system to charge. Good Luck.



James Northum

DTT installer/dealer/Bill K. approved builder

 

[SRehberg]

INARUSH76



Thanks for all the help, that check valve is going to have a vasectomy ASAP. I always try to start up the truck in neutral, as the flow charts seem to show it is lubed in neutral, but not park.

I wondered if the Dodge mechanic misaligned the bearing carrier with the lube hole and then blamed the check valve to cover his behind. The check valve never gave any trouble until he redid the trans, so I'm naturally suspicious. When the trans seized, the check valve was blamed.



I really appreciate all the time you have taken with me and when I get to the problem, I will followup and let you know how it went. I think you hit the nail on the head. THANK YOU





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'96 2wd with a short lived check valve!

 

[inarush76]

hang in there

You are welcome, if I can help with anything else let me know. To clarify, the support will only bolt in one way so it could not have been misaligned. I would still be suspect of the cooler since there was a converter failure. Good Luck.

James

 

[diesaldual]

SRehberg,

Sounds like you have all the same problems as I did before my transmission fell. The piston seal got stuck on mine for some unknown reason and starved mine of fluid and also caused mt front band to hang up. Which all turned catastrofic. Fried that baby. .

I had a friend rebuild mine with the help of Bill Kondaly. .

Bill helped us find what went wrong and also help fix any of the past problems I had.

Give Bill a yell he is very helpful and knows his trannys. .

Sorry I could not be of more help.