47 re stuck in limp mode. Help!!

jakesaxton91

jakesaxton91

Blacksnake
Joined
Oct 11, 2013
Messages
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Hello all. I recently purchased a 99 4x4 auto regular cab with 106k miles. I was very hesitant on buying an auto but I couldn't pass up the deal. I drove it twice before I bought it, no issues. Only mods were Edge EZ 65 horse programmer and straight exhaust. The trans was supposedly built 1000 miles ago to withstand 600 hp.... No receipts. Anyways the truck ran great all the way home ( 35 miles ). Next day it would start out in 3rd gear. I could manually shift it into 1st and 2nd and up to third but it would not shift to 4th nor overdrive. I started with the fluid, it was past the full line by an inch or so. After searching the internet and asking certified mechanics about my issue I started with the speed sensor on the drivers side of the transmission. No dice. Then I dropped the pan and replaced the governor pressure solenoid and the governor pressure solenoid. Still nothing changed. So I dropped the pan a second time and replaced the overdrive solenoid alon with the lockout solenoid. Nothing!!! I used DEX MERC as advised by my transmission shop. Also the pan had nothing out of the ordinary lying in it. I dropped the truck off at a reputable diesel mechanic last week and he hasn't really had time to look into the trans. I'm getting the truck back tomorrow because he's going on vacation for a week. Only thing he found so far was when in Drive ( D ), the pressure was at 50 psi! I'm stumped and quite bummed. Any and all ideas would be appreciated. I'm borrowing a scan tool tomorrow to see if any codes are poppin up, I have no CEL on at the moment. I know this is a long write up but my situation seems different than anyone else's. Thanks!
 
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Check the simple stuff first, is it getting power to the trans? 50psi seems a little low for a built trans.. Let us know the codes once u scan it. If all else fails just jumper the relay.


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I will try that tomorrow. Forgot to ad that I cleaned the battery terminals and left the batteries unhooked for a half hour to attempt to reset the ECM
 
Changed nothing. One thing I did notice was that after I put the governor pressure solenoid and pressure sensor in, it tried to start out in first for a second but has been starting out in 3rd since ...
 
Maybe it will throw a code and give us a direction to go in, if not then it's he old fashion way with checking power and connections. Do u have a pin out of the connector on the side of the trans?


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The only thing that pulling the battery connections resets is the APPS settings. It will not remove codes or reset the ECM/PCM.
Check & clean all connections, then slather them with silicone di-electric grease (NAPA for a big tube)
When I say all connections, I mean ALL connections in the engine bay & transmission.
Also, check the alternator for .3 volts AC or more with a quality volt meter.
Some high performance transmissions & valve bodies come with a resistor to fool the ECM into thinking the pressure is lower than it really is & without, you may have limp mode.
If you can access a DRB3, you can command the transmission to engage gears & see if it is the electrical/electronic/ECM/PCM or the trans itself.

Ed
 
Thanks I did pick up some di-electric grease. Going spray all connections tonight. The guy I took it to told me about the resistor but in his opinion said that it would not help. I just picked the truck up from the shop ( since my mechanic is leaving for vacation for a week) to try and figure it out myself. The shop is 3 miles from my home and the truck died on me twice. Also there was barely enough power to get up hills. When it dies, sometimes the fuel pump will not kick on after you turn on and off the key. I was stuck on the side of the road and the only way it would start is if I pumped the gas like an old carbureted motor. Odd. I checked the codes and only a p0237 (turbo sensor "A" circuit low). I will check the alternator also. Batteries were almost dead today also. I don't get it, the truck ran great, shifted great, and held a good charge a week ago!!
 
pratherjoe said:
Maybe it will throw a code and give us a direction to go in, if not then it's he old fashion way with checking power and connections. Do u have a pin out of the connector on the side of the trans?


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Click to expand...

All pins look to be intact.
 
Fill out your sig in the "User CP" with EVERYTHING on the truck. That will assist in diagnosis. I will venture a guess that a diode or diodes are going bad in your alternator & discharging the battery. Having good batteries & alternator are critical in our bastard generation between fully mechanical & fully electronic.
Go to http://www.mopar1973man.com & find the articles on your code. It will have full diagnostic procedures.
Also, if you have a tuner, completely remove it & return the harness & sensors to stock to eliminate it.

Ed
 
I will work on that. Alternator seems to be charging fine. I think the batteries were dead because the mechanic that worked on it unplugged the ecm when he drove it. I cut the original terminal clamps off and put 4 new on but it didnt change anything. My buddy cracked a couple lines and it ran good until I drove it down the drive. Its still shutting off randomly, I even wired the relay to kick on when the key is on. I dont get it, I bought electric diode grease and sprayed most of the connections but im not done yet. Im running out of options i feel.
 
I had a similar issue when I put the 12V in my '98. Tranny in limp mode and no charging. Also noticed my fuel gauge didn't work. FINALLY found a connector that was together but not fully snapped together. It was one of the three connectors on the fire wall right above the master cylinder. Check an make sure they're fully connected.

connectors_zpse352b13c.jpg
 
Nope still nothing. Checked, cleaned and lathered some diode grease to the connections. Wont start unless I pump the gas.
 
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