Archived T/C wont lockup

[Hummin Cummins]

Everything has been working perfectly until last night. I got my TT out of storage, got coffee and started up the road. I have a force unlock switch on the floor. Once I got rolling I could not get the t/c to lock up. It worked fine before I stopped. I tested the floor switch, its fine. Took plug off temp sender, sprayed with electric cleaner, took plug of the other thingy on the side of transmission and cleaned that plug, still no go. Is there a fuse or relay somewhere? Can I reset the PCM somehow? I'm out of ideas.



Chris

 

[jnelson]

There is a relay under the hood in the fuse box. it usually has a jumper in its place if you have a lock up switch.



There is a solenoid in the valve body that send s the TC into lock up. A good tech can jump wires to "hear" the solenoid.



When mine would not lock up - it was a little broken peice in the VB. When they dropped the pan it was laying in the transmission fluid. Took them about 10 minutes to fix.



Hope this helps.

 

[jlhartak]

Sounds like your trouble started when you hooked up the Travel Trailer?? I would start checking all the fuses in the left end of the dash and under the hood. Have you double checked the trany fluid level? low fluid can keep the TC from locking up.

 

[Hummin Cummins]

Checked fluid level, checked the fuses and relays. I just jumped the temp sensor gonna go for a test ride.



It worked for about 5 miles after I had my camper. After I stopped for coffee, I always unlock my t/c before going again. When I got to speed, it would not lock. I'm gonna change the fluid this week hope its not internal.

 

[Hummin Cummins]

Heres what I have done so far

Checked fluid level



Totally removed unlock switch and soldered wires back to stock



Tried to jump temp sensor, got a transmission temp light and no O/D so I assume it is working



Cleaned all electronic plugs on side of transmission



Checked for movement of cable, have 1/8 or 3/16 travel at WOT



Checked continuity of relays and fuses



Lastly... Tried to force lock the t/c by grounding the org/blk wire and still no lockup



I guess it is the solenoid rather than the PCM since everything else on the truck is working fine.



Is this a DIY fix or do I need to see a pro?

 

[Joe G.]

First of all, you have a 47RH transmission in your '95, NOT a 47RE so there is no jumper wire or relay involved with the lockup. The connector has three wires. One is 12 volts the others are used to provide grounds to the OD or TCC solenoids. If your OD is working then the 12 volts is ok so the problem is either with the ground or the solenoid. If you don't have a service manual you REALLY need one for the circuit wiring diagrams. You can test the solenoid by jumping a ground to the solenoid wire in the connector and taking a test ride to see if it locks up. If it does then you have a problem in the circuit.

 

[amsoilman]

I'm with Joe, go with what he says!



Wayne

amsoilman

 

[Hummin Cummins]

Well,

I did more poking and prodding. I have a good 12v on the hot wire, OD is working fine. I went to ground for the lockup solenoid and test drove, still nothing. Checked continuity from the PCM to the connector on the transmission and is fine. I guess its the solenoid (I hope). Off to the transmission guy tomorrow.



I was hoping you would see this Joe. When it comes to the lockup electricals you seem to always help.

Thanks



Will keep updated tomorrow.

 

[Hummin Cummins]

Well,

Went to transmission shop today. They test drove and said that the t/c clutch was gone. They told me if it was a solenoid, that I would have a check engine light, which I dont.



Just my luck, I knew It wouldn't last forever

 

[BillGotthelf]

Since you have to get new TC maybe you should look into one that will hold the extra power.

 

[Joe G.]

Chris,



I don't think you can get a CEL with a '95 diesel. I've never had one and I've screwed up the wiring a few times so I should have. I don't see how a solenoid failure can cause a CEL. If it was a dead short then a fuse would blow. If an open circuit would cause one, then all these mystery switches would be setting off the CEL. I'm not even sure the diesel has a bulb in the socket. The socalled computer in a '95 has no input from the transmission to determine if the TCC solenoid is working or not. I'll check my manual later to make sure that's a correct statement but if I were you I would be from Missouri about that one. Usually if the TCC goes out it chatters and slips before giving up. It just doesn't quit with no complaint like that. If someone else has better info about a 47RH transmission jump right in. I may have a bad case of hoof-in-mouth here.

 

[Hummin Cummins]

Joe,

I agree with you totally. My t/c has slipped before, but for a complete failure, I would think there would be more catastrophic slipping and noises. It didnt dawn on me at the time, but you are right, my force unlock switch would cause a light every time. I was a little distrubed after my trip to the transmission shop. I felt sure that if the t/c "blew up" there would be enough material to screw up other things. I came home and called DTT right away and got some tech advice. It looks like its 99% the solenoid that is bad. I am going to cut and splice the ground wire right at the transmission tomorrow and try to force lockup. The first time I did it was at the PCM. If it dont go then, I'll replace the solenoid and go from there.



That guy almost had me talked into a transmission rebuild. (not that I dont need one anyway, but the checkbook says I dont)



I haven't read alot about these solenoid problems here, but I guess most guys have their transmission rebuilt before they go bad. Anyone give me any hints on changing them? I'll talk to the boys at DTT tomorrow. I'll buy the solenoids from them to pay back for the free advice. LOL but I hate bothering them I know they have more things to do than talk some transmission challenged guy like me through something stupid when its not even their transmission.

 

[Joe G.]

Chris,



Changing the solenoids on a 47RH is a piece of cake except that you have to take the VB out to do it. This is where the big difference is between the 47RH and the 47RE ('96 - '02). There are two solenoids on the side of the valve body. If you don't have a service manual you REALLY should have one. Taking the VB out is a PITA because of the park rod. If you have not done this before and don't have a service manual you will have to have someone else do it.

 

[Hummin Cummins]

Joe,

Got my service manual today. I called the dealer and ordered the solenoid. Talked to their transmission guy and he wants to put it on the scanner first. I read my manual and I'm not sure about doing the job myself. From what I read, It sounds fairly straightforward, I just hope that the solenoid is the problem. From what I read in the manual, the scanner will only pick up an electrical fault, but wont leave a code if the solenoid itself is bad or stuck. I guess if its not, I still have 2 weeks till my trip I guess thats enough time to get an aftermarket transmission of my choice stuffed in there. Heck, maybe while I'm waiting on my truck at the dealer I'll just buy that 03 black 4 door 6 speed sitting on the lot.

 

[Joe G.]

I wonder what they can see on a scanner that says anything about a 47RH transmission. Especially, since you have a switch in the system. The 47RE is controlled electronically, so a scanner makes sense for it.



One thing about the description in the manual that is a left over from older torqueflite transmissions that does not really apply to this one is the park rod removal. The park rod MUST stay in the trasmission. Remove the e-clip from the valve body end of the rod and push the end of the rod up out of the manual shift mechanism. The shifter must be in 1st to do this. You might want to get a few extra e-clips because putting it back in is a little tricky if you don't have a special tool. A pencil magnet is a must.



Another thing is that when the VB is pulled out the accumulator spring and piston will fall out on the floor. I made a little clip from a piece of plummers tape to hold it in to prevent that. I lower the VB a little, then push the clip under the spring. The other end of the clip fits over the edge of the transmission case. A look at the pictures in your service manual will make this make a little more sense.

 

[Hummin Cummins]

Good trip to the dealer

Went to the dealer at 12:30 today. I explained to the tech what I have discussed here and what I have checked. He was very knowledgeable. He was familiar with the mystery switches, torque plate setups and other BOMBS. He scanned it, found 3 codes for the solenoid pack. Went to the parts counter and got the one that I ordered the other day. Put it in, took for a test ride and everything was fine.



Had him do the TSB 21-04-95 reflash. He had to work at it a little to get it to take. It did, and man what a difference that makes. Under light throttle (my normal driving) Lockup in OD occurs at 52 mph now instead of 45. I cant wait to see how it tows now.



Thanks Joe for your help. It took a week but I'm glad it wasn't anything major.



Chris