Engine/Transmission (1994 - 1998) T/C won't lock up

[ronco]

I tried to search for this topic, but the search engine didn't comply. My T/C suddenly stopped locking up recently. I stopped the truck and checked the fluid level and had to add some, but no luck. I have substituted a proper resistor for the trans. temp switch and got no luck either. I cleaned the small wires on the drivers side battery cable and attached them to the PDC and got nowhere. Next step is to run wires to the harness to manually engage the T/C while driving to troubleshoot the PCM.



Any other advice?



Thanks,



Ronco

 

[Ben Rumson]

... Next step is to run wires to the harness to manually engage the T/C while driving to troubleshoot the PCM.



GOOD CALL. THis will tell you if it's a manual problem within the transmission or something electrical - upstream.



Good luck.

- Ben

 

[Howard Durand]

Ronco,

The two solenoids that operate overdrive and TC lockup are inside the transmission. The cable that runs to it is made up of 3 wires. The light green/black wire is the 12 volt power wire. The brown wire is for the OD solenoid. It connects to pin 55 of the PCM. Obviously they are both OK since overdrive works.



The orange/black wire is for the TC solenoid. It comes off of PCM pin 54.

Clip into that one and, with the ignition key on, connect a voltmeter between that wire and ground. You should measure 12 volts. If not, the solenoid is either bad or you have an open circuit somewhere. If you do have voltage, the solenoid is OK so you may have a problem with the PCM.



If you think the solenoid is bad, pull the pan and check it there. If it does turn out to be bad, PM me. I kept the solenoids off of the valve body I returned to BD when I bought one of their upgraded VB's.

Pay the postage and you can have them.

 

[ronco]

Howard,



Thanks for the offer! I have had my butt worked off lately and don't really have the time to dig very far for a problem. I don't have a garage to work in, so the cold driveway is not very inviting. I loaded the truck this morning on a roll back and took it to the trans. shop that made my mods last year. He feels like it is a lock up solenoid will get the truck back early next week.



Once again, thanks for the offer!



Ronco

 

[bmoeller]

Did you check the throttle position sensor? Not sure if the 47RH has one, like the 47RE, but I've had to clean mine before. It was hunting in and out of O/D in my case.



Just a thought.

 

[ronco]

Update

My trans. man called this afternoon. The "piston" within the T/C appearantly failed and will not lock the convertor. The T/C will be removed and shipped to the manufacturer and repaired. There is no warranty even though the convertor is less than a year old. I was told the repair for the convertor alone will be $200-$250 dollars.

 

[KB0OU]

Should order a DTT TC, it should last forever,, or about so.

 

[JPittinger]

Ronco- I know that triples are what everyone talks about, but you can get a single disk converter for alot less. It would be worth a few hundred bucks more than your repair bill to upgrade. I got a single from Dave Goerend... 50k mile warranty if I keep it under 500 hp. The change in fluid coupling alone is worth the $.

JJ

 

[ronco]

Should order a DTT TC, it should last forever,, or about so.

I gave that some consideration when my mechanic said the T/C went south!

However, to my knowledge, none of the manufacturers will sell you just a convertor. I already have a Sun Coast v/b and the rest of the transmission has been working well, just the T/C failure.



Ronco

 

[KB0OU]

When I got my DTT that is all they sold me. ?Why would they not sell you one??

 

[ronco]

When I got my DTT that is all they sold me. ?Why would they not sell you one??

As I understand it,



HP + stock trans + aftermarket conv. = misery.



Appearantly, someone in the past did what my equation said and ended up bad mouthing a convertor manufacturer because the convertor failed. The convertor probably failed because the stock pump pressure will not fully engage the aftermarket T/C clutch. I can understand the reluctance based on what can happen mixing parts. A good convertor added to a stock trans. is not a recipe for reliability. My trans was built from various vendors.



Ronco

 

[ChadHarlan]

I am pretty sure you can get just a converter from most places.

 

[ronco]

Final Update

The manufacturer cut the T/C open on Monday morning and found the clutch had de-laminated. The clutch was replaced as well as the piston that engages the clutch. They have seen a few T/C do this, but don't think there is a problem overall. Everything is working well now. Thanks to everyone for your suggestions. In honor of this event, I ordered an exhaust system from Rip to make me feel better





Ronco