Engine/Transmission (1998.5 - 2002) 47 re transmission problems AGAIN

[DFerverda]

98.5 2500 4x4 Took the mad out.

Sorry if this ends up being long, I lost the flex plate 3 months ago in little rock, put in new one but then imput shaft broke and had a transmission shop rebuild. Got 30 miles and it would not shift to OD. Took it back and took shop manager for a ride, went right in. He thought it was a glitch and said go on. Got to Victoria Tx and spent the night next morning same thing. About 30 miles later it shifted and worked all day. Got to Port A and dropped trailer, 32 Ft toyhauler. transmission worked ok for next month not pulling.

Headed home to Indiana, got to Galviston , Acting up headed to Little Rock. Had to drop trailer in Center Tx, truck would not pull it. Made it to LR Torque Converter gone, They rebuilt it again (2nd time). Shop said thought apps bad, so i replaced it. Truck acted good, Back to center and picked up trailer, back to LR on to Memphis, 92 miles from Nashville it blew up again. Towed to Nashville and had Another shop fix it. They put in a new TC and rebuilt with stock electronics It worked and shifted good still missing od on occasion. Pulled to sons house in Southern Indiana, 35 miles from Louisville. Dropped trailer and went home, (been gone 3 months and HAD to make it home).

Went to local transmission guy, and he regrounded the apps wire and tested with scanner. It worked like a champ for 3 weeks, shifted as should sooooooo went to pick up trailer, it acted perfect for 15 miles, no OD AGAIN, Got home with od locked out.

Been home a week still no od.transmission guy thinks it is in electronics. I tried to put in switch O/BK wire on pcm with switch to ground and nothing. Will not shift to od. I have 1,2,3 lockup but no 4th No codes.
Searched on here for a week and found a lot of things but no joy.

Questions, Which wire in transmission plug should be hot (12V) i have one with 8 volts and one with 5 but no 12volt ? And can you test these with plug unpluged from transmission. Which wire on pcm should be right wire for lockup switch. Any ideas where else to look?

I am at a loss where to go from here. transmission guy gave up, I need my OD back. I have put on 2nd new apps, new brake switch, new headlight switch, new abs, speed sensor in rearend, new Ignition switch, the list goes on. HELP>

Dirk

 

[SnoKing]

Does the OD lockout light on the dash work correctly via the button.

You may have PCM problem. I believe it is in the voltage path to the transmission, and provides ground to TC lock up solenoid and overdrive solenoid to pull them. You should see battery voltage on these leads when running and ground when the PCM pulls them. I can post colors later when I get home.

TC might not be locking also. Did you replace the transmission relay in the distribution panel on drivers fender liner? This may be your issue!!! Have you cleaned all the grounds under the hood? Have you read codes? Snoking

 

[DFerverda]

Yes it works fine, the od button, If you are going 55 locked out and try to shift to od the rpm's come up slightly and just hang there.
Yes i have cleaned every ground added 2 from battery to frame and engine block, and one to the pcm itself and grounded the black wire on the apps.
I read a post you and cerberusiam said one wire in the plug will have 12 volts, i cannot find that wire only 5 and 8 volts so i wonder if it is open in the harness. A diagram or wire color would be great.
The tc does lock in third, I am pretty sure.
I replaced the relay with the one from the ac and tried the trailer one. and jumpered it straight no joy. No codes

 

[DFerverda]

I found a site on ebay, in Illinois that will repair my pcm for like 140 bucks and i am not above sending it in, if need be. I ordered a book on my transmission and they sent me the one for the rh so i reordered the RE it should be here this week. Seems i lost od right after the flex plate transmission bust the first time.It would come and go when it wanted but mostly when i loaded the truck with 5er. But it is now MIA altogether. If i knew what the wires in the transmission plug should be seeing I think I could figure this mess out, I also have a ground from battery to alt.
The 1,2,3 shifts are good and on time just no 4. I just installed a temp gauge in test port transmission, when running so far never over 150 degree f. But i don't drive any farther then i have to, till i get this thing whipped. I also installed new transmission cooler and took the old one out, as i was afraid it may have debris in it. Thanks Dirk

 

[SnoKing]

OK here is the diagram for my 2001, I would think the 98.5 has the same colors. The red wire going to the transmission should have 12V+ going to the transmission with the engine running. The brown is the other side of the OD solenoid and should have the same voltage just sitting with the motor running. The PCM grounds this lead to pick the solenoid and engage OD. The same with TC lock up. should see same battery voltage just sitting running on the OR/BK wire. When it locks the TC the PCM grounds that lead.

The PK wire from the PCM controls the Transmission Control Relay. All of these wires are in plug C2 at the PCM. SNOKING

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[DFerverda]

With motor running the red wire at the transmission reads 1.432 volts and the brown reads 1.262 vdc with my fluke. This is not enough, I will pull air cleaner tomorrow and check these wires at pcm, it is raining right now and i am already wet but just got back from dropping off grandson #2 in indy, long haul. Is there a way to check the pcm to see if it is in fact doing what it should or just check the wiring ? Thanks Dirk

 

[SnoKing]

Are those readings with the connector still plugged into to transmission or with it disconnected. If connected unplug it and check voltage. Harness may be shorted inside transmission or one of the solenoids is toast and shorted. Snoking

 

[DFerverda]

Ok i will check that tomorrow, I used a pin and stuck the wire while it was plugged in. I will unplug it and check again tomorrow if it quits raining I might just clean out a spot in the shop and let it drip dry. Thanks for the diagram it will help. Dirk

 

[DFerverda]

With the key on connector unplugged red wire reads 5.13vdc and the brown reads the same. Start truck and red and brown read 0 to 0.12 nothing. At one time i thought i saw the red wire hop up to 13. something just as i started the truck, but went to 0.
Get a higher reading with connector unplugged and key on.
Does this mean i have a short or ground in the transmission . Dirk

 

[SnoKing]

Remove the transmission relay and install a jumper between the contacts that the relay closes. I think they are the two side by side that run left to right across the truck. One should have battery voltage all the time. 87 and 30 terminals. Relay should be labeled this way. Then see if you have voltage on red lead at transmission unconnected. Snoking

 

[DFerverda]

OK jumper in place unplugged , key on red reads 12.41 brown reads 5.13 Start truck red reads 13.33 brown still reads 5.13.

 

[DFerverda]

Put plug back in transmission read the brown wire now reads 12.35 with jumper in place. So have voltage going in and out.

 

[SnoKing]

Take it for a test drive.

 

[DFerverda]

I did nope 2100rpm at 55 when working it is 1400 at 55. the jumper still in.
This thing worked flawless for 3 weeks and probably 1500 miles not towing, hooked up the fifth wheel and pulled it 15 miles it shifted perfect 1,2,3,4 lockup then it quit, would not shift into od. It finally shifted after we did just short of 100 miles (I kept trying it every 10 miles or so) and od worked fine for the next 55 miles, I got off 69 and it would not go back into od and has not for the last 2 weeks.

 

[SnoKing]

So earlier you said you grounded Or/Bk wire. That locks TC. BR (brown) wire shifts into OD! Test that and if you get OD then you might have a PCM problem. Snoking

 

[DFerverda]

You mean put a ground via switch on the brown wire?

 

[SnoKing]

Yes get to 55 and flip switch. If it goes into OD you do not have a mechanical problem or solenoid problem. Snoking

 

[DFerverda]

Nope nothing. I tapped the brown wire at pcm c2 pin 21 With jumper in place read voltage, other side of switch to battery, Flip switch at 55 nothing no rpm change at all.
so it looks like a bad overdrive solenoid?

 

[SnoKing]

You have to ground the brown wire to pull up the solenoid. The solenoids have battery voltage to one side and the PCM grounds the other side to pull them. Chris

 

[DFerverda]

Yes the other side of switch to battery ground the other one is tapped to the brown wire, just up by the pcm.