help with 47rh no OD

camarokiller

camarokiller

New member
Joined
Jun 16, 2012
Messages
747
I know, i know, SEARCH! Well i did, and nothing i could find on here or google ever had a solution. The threads just stop.

What im working with. 1995 RCSB Project. Truck has a 47rh(always has) it has and unknown shift kit and converter. Truck has sat for 2 plus years. Before it was parked it suffered from sporadic shifts and constant limp mode. Well before i got it back on the road a few weeks ago i put the resistor in place of the trans temp sensor, and the bad shifts and limp mode were fixed. The tuck has always had a bad trans leak due to a cracked rear cooler port, so i took care of that a few days ago. I had the pan off at that time and the pan magnent and fluid was all clean. Ever since i have got it back together i have had no 3rd gear lockup and no overdrive(lockup switch still works in 2nd and 3rd). I also have no cruise or od cancel button. Ive checked all fuses and checked the TPS, and even tried a known good one. I know some one here has had this problem. PLEASE HELP COMP D!!
 
Do you have access to a scan tool? If so try commanding the LU and OD solenoids on and off with the key on engine off and see if you can hear them clicking from underneath the truck. A 47RH doesn't have a "limp mode" since 1st through 3rd are controlled purely by hydraulics and mechanical springs, and a mechanical governor.
 
my truck had the same problem i took it to mighty transmissions. they changed the converter and adjusted line pressures... possibly give them a call they are open for another hour and 30 mins. 336-406-5319
 
stubz616 said:
Do you have access to a scan tool? If so try commanding the LU and OD solenoids on and off with the key on engine off and see if you can hear them clicking from underneath the truck. A 47RH doesn't have a "limp mode" since 1st through 3rd are controlled purely by hydraulics and mechanical springs, and a mechanical governor.
Click to expand...

I have no scan tool and live in BFE. What mean by limp mode was the faulty temp sensor disabling OD. Im leaning towatd the OD solenoid, but just want conformation that it is the problem, and messing with the cruise and od cancel button as well. Im laid off and cant afford to throw money at it right now.
 
BHARRIS said:
my truck had the same problem i took it to mighty transmissions. they changed the converter and adjusted line pressures... possibly give them a call they are open for another hour and 30 mins. 336-406-5319
Click to expand...


I doubt i have a line preasure or convertor issue. I have a solid 1-2 and 2-3 shift and can force lockup
 
Good chance your OD piston seal dried up and cracked if it sat for so long. I may be eating crayons here but the first thing Id do is hook up a pressure gauge to the OD port and see what happens when you are supposed to hit OD. No pressure equals blown seal.
 
CSnyder said:
Good chance your OD piston seal dried up and cracked if it sat for so long. I may be eating crayons here but the first thing Id do is hook up a pressure gauge to the OD port and see what happens when you are supposed to hit OD. No pressure equals blown seal.
Click to expand...

Thank you. Ill see about getting a gauge tomorrow. If i have the proper pressure, what else could it be? I had my od and lockup for the first few days i drove it BTW.

Thanks for the help
 
Big Blue24 said:
No, a bad solenoid = no overdrive shift period.
Click to expand...

Would it also equate to the OD lockout button not lighting and no cruise?
Just bought a 200psi guage (highst rural kings gauges went to) and will check my pressure tomorrow.

Thanks Chris and Will
 
Last edited:
No cruise, no LU, and No OD sounds like a PCM issue.

Just on the trans issue, the sudden loss of Overdrive and TCC at the same time sounds like wiring. Could be a voltage supply or return issue, or both (a connector loose). Supply and return are dictated by the PCM so...

What was it doing when you thought it was in limp mode?

Sent from my XT1053 using Tapatalk
 
biggy238 said:
No cruise, no LU, and No OD sounds like a PCM issue.

Just on the trans issue, the sudden loss of Overdrive and TCC at the same time sounds like wiring. Could be a voltage supply or return issue, or both (a connector loose). Supply and return are dictated by the PCM so...

What was it doing when you thought it was in limp mode?

Sent from my XT1053 using Tapatalk
Click to expand...

Bad temp sensor thinking it was hot and canceling OD(i have since wired in the correct resistor, and it was working) Hope its something simple as a loose connector. Gonna clean the plug and socket for the OD solenoid tomorrow first thing. Thats the only thing i disturbed when i fixed the rear cooler port.
 
Last edited:
Again. Thanks to everyone that is helping. I cant believe all the threads with my symptoms that were left open ended. You can bet ill post the solution when i find it
 
Found how to test the PCM to see if it commands OD. Will do this tomorrow too. Id honestly rather spend a little more money and change a bad PCM rather than a OD solenoid. The thought of dropping the VB makes me sick
 
camarokiller said:
Found how to test the PCM to see if it commands OD. Will do this tomorrow too. Id honestly rather spend a little more money and change a bad PCM rather than a OD solenoid. The thought of dropping the VB makes me sick
Click to expand...

No worries, Its not bad to drop the valve body!!!
 
Foster#17 said:
No worries, Its not bad to drop the valve body!!!
Click to expand...

I do maintenence in a coal mine, i can handle about anything, but the thought of those little check balls falling out makes me cringe. If its the case ill get the solenoid and pay the tranny shop across the river to install it LOL
 
You can drop the valve body without actually taking the valve body apart. No check balls will fall out unless u take the torx screws out. Hardest part is the park rod and it's not bad after the first time.
 
R1raptor said:
You can drop the valve body without actually taking the valve body apart. No check balls will fall out unless u take the torx screws out. Hardest part is the park rod and it's not bad after the first time.
Click to expand...

Hmm. That sounds not to bad then. If i find the solenoid to be the issue ill have to read into it more.

Thank!
 
*update*

Just went out and back probed PCM pin #55 and went for a drive. I had a steady 13.5 volts in every gear, and when over drive should have hit(should drop to 0V on OD shift). I got up to 55MPH and grounded my test lead on the lighter, and BINGO OD!

Now then. I belive this is a PCM or speed sensor on the tail housing problem.

HERES A RECAP OF ALL MY SYMPTOMS:
no lockup in 3rd (can be forced with my switch)
No od (can be forced by grounding pin 55)
No cruise
OD cancel light will not iluminate
JUST NOTICED TODAY THAT MY OVERHEAD DISPLAY(with temp and compass) was acting very funky flashing all sorts of weird things.


You guys think this is the PCM?
 
You must log in or register to reply here.
Back
Top