anyone good w/ mopar 47RE trannies? Technical shit inside...

[flubyux2]

soo, ive been having some issues w/ the 47RE in my 97 Dodge ram 2500 cummins 2wd truck. from a stop, the rpms will go to 2000ish if i go past 25% throttle and its a sluggish up to 40mph. all the upshifts are soft but not slow. once TCC engages and the converter locks up, rpms drop about 600-700rpm and the truck lurches forward and picks up speed unless i edge out of the throttle. its slow as balls off the line, like inadequate line pressure or its just starting out in 2nd/3rd gear, like limp mode. ive been going thru the simplest/cheapest steps to the most complicated/expensive.

first, i took it to autozone and had the codes pulled w/ a cheap actron scanner. it came back w/ a bad Output shaft speed sensor. makes sense, my speedo was acting up. i replaced that for under $20, speedo fixed and code is gone. i still have codes P1762 and P1763.

i do a search, find out they mean "Governor pressure sensor voltage offset" and "Governor pressure sensor voltage too high". well what the hell does that mean and what makes that happen?

i thought maybe the GPS voltage had something to do w/ TPS voltage to maybe increase the line pressure as the TPS % increases. i recalibrate the idle to 700 hot, in gear. then i readjuste the linkage from the TPS to the injection pump; my TPS idle voltage and WOT voltage are now in spec. P1762 and P1763 are still there, no dice.

i do more research, Dano moparo says that its more likely a bad transducer than the Governor pressure sensor itself. other possible culprits are;
-Transmission fluid level and condition
-Powertrain Control Module
-Sensor ground circuit open
-Intermittent GPS signal
-5 volt supply circuit open inside transmission
-GPS ground circuit open inside transmission
-Bad GPS

alot of potentially expensive problems to fix.

well, tonight, my friend brings out his Solis OBD scanner... one of those $6000 scanners from Snap-On. well i go into tranny diagnostics and im looking at some parameters;
Des Gov Press; 0 (truck on/off/idling/in park/in gear not moving)
Gov press kpa; 738
gov press v; 4.96
Gear; 1

so once i start to roll, the Des Gov press climbs. as road speed increases from 0-40mph, Des Gov Press climbs and peaks at 696 kpa, never any higher. the Gear indicator on the screen goes 1, 2, 3, 4 and the TCC solenoid says "on" to indicate converter lockup. the tranny seems to operate normally, except for the GPS parameters and excessive slippage/sluggish starts.

even w/ the truck off, key on, the Gov Press kpa says 738 and Gov press v says 4.96... these values never change. this isnt right, is it? its like something is sending the GPS too high of a voltage input (which explains the code P1763)... but where does that signal come from, the "transducer"?

also, would a faulty transducer explain why the truck is so slow off the line and feels like its slipping? or do i need to re-adjust my clutch bands?

regards
chris

[Puto]

Have you tried disconnecting the (-) batt cable to reset codes, in order to see how it behaves and to see long it takes to give you those codes again? Not that this will help much, but sometimes it helps to further diag the car.

[flubyux2]

ive cleared the codes by cycling the key 4 times, cleared it twice w/ the actron scanner and cleared it tonight w/ the Solis. the first couple of times of cycling the key, i was able to acheive a normal-feeling 1st gear. id put it in drive and the truck would take off from a stop briskly, then upshift rather firmly. after that, it wouldnt ever run like that again; back to the sluggist/slipping starts.

even after clearing the codes w/ the bad-ass scantool, my Gov press KPa was still pegged at 738 and the Gove press v was still pegged at 4.96v too. truck still exhibited the same drivability problems as before.

[Dano Moparo]

NO: 21-04-00

SUBJECT: Erroneous MIL Illumination For P1763 – Trans. Governor Pressure Sensor Volts Too High

DATE: June 30, 2000

THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-07-99, DATED APRIL 30, 1999, WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDE REVISED MODEL YEARS.
OVERVIEW:

This bulletin involves selectively erasing and reprogramming the JTEC Powertrain Control Module (PCM) with new software (calibration change 96Cal18, 97Cal18, 98Cal12, and 99Cal14).
NOTE: THIS INFORMATION APPLIES TO VEHICLES EQUIPPED WITH AN RE SERIES AUTOMATIC TRANSMISSION BUILT BEFORE DECEMBER 18, 1998 (MDH 1218XX).
SYMPTOM/CONDITION:

Some vehicles may exhibit a MIL illumination with a Diagnostic Trouble Code (DTC) of P1763 –Transmission Governor Pressure Sensor Volts Too High. The vehicle operator may experience slower than normal vehicle accelerations because the transmission may have temporarily entered its third gear "Limp-In" mode as a result of the DTC. The "Limp-In" mode may last until the vehicle owner cycles the ignition key. The technician may not detect a problem with the automatic transmission during a diagnostic test or test drive.
The MIL is caused by an increase in hydraulic pressure. The increased hydraulic pressure is the result of a new valve body machining process, which entered into production January 1, 1998. This condition will occur most often with vehicles that were built between January 1, 1998 and December 18, 1998.
Vehicles built prior to January 1, 1998 may also experience this condition if the valve body or the transmission assembly is replaced with components built after January 1, 1998.

[Dano Moparo]

I don't know if the $6k snap-on scanner will do what is required to do the updates. It might be better to go and pay $40-$80 at the dealer and have it done with the DRB. I hope this helps.

And moving this to Dodge tech.

[flubyux2]

the Solis scanner wouldnt reflash as far as i could tell. does my Gov press V and Gov press KPa sound correct to you? i dont know if those are preset limits that the scantool reads off the JTEC, or if the scanner is being told those conditions exist when they really dont. i remember you said the transducer is usually faulty even though the GPS code is set. does the Transducer convert pressre signal into voltage signal and send it to the GPS? i think thats what trandsucers do, anyways.

i did see that TSB on cumminsdatabase.com too. i do know that my current tranny is NOT the stock one. so i could see how this is a later model tranny comflicting w/ the parameters preset in the JTEC module since my truck is built in 11/96.

but, if the transducer turns out to be fine... then reflashing my JTEC powertrain module should alleviate these problems?

btw, if my front and rear bands were out of adjustment, would it create/compound these problems? just wondering if these symptoms are an indication of loose bands.

[flybyuin2.2]

It sounds like the 1/2 shift solenoid is sticking and making it take off in 2nd gear which will make it feel very sluggish, have you tried shifting it manually?

[BlackWind]

^ to do a reflash, you need to get a drbIII and connect to techtools, only available in the dealership, go into the tcm module, get the part number, go to the techtools on the computer, connect the drbIII using the red bus cable, download the flash to the drb, then reconnect it to the vehicle and reflash the tcm. If the tsb was the issue, then it should be ok, if not, overhaul the whole thing.(IMO)

[flubyux2]

Originally Posted by flybyuin2.2

It sounds like the 1/2 shift solenoid is sticking and making it take off in 2nd gear which will make it feel very sluggish, have you tried shifting it manually?

thats what it FEELS like. i have tried to manually select 1st, but it drives the same as manually selecting 2nd or D. it starts out and SEEMS like the same gear from 0-40/50mph depending on throttle angle. i can feel 2 upshifts and the TC lockup. the upshifts dont cause an RPM drop at all... not like a gasser normally does when it goes thru the gears.

modman... i do want to go to the dealer but cant make it this week. would the TSB cause my Governor pressure KPa to show 738 on the scantool and Governor pressure voltage to show 4.96v under any/all conditions? i would assume even a PROPER working tranny (updated valvebody in older truck) would still display varying Governor pressures and voltages. they are both pegged like something is shorted or stuck.

can anyone tell me more about the transducer? such as, is it responsible for reading pressure and converting it into a voltage that the GPS reads? where can i find the transducer?

edit; i found a TSB w/ a pic of the pressure sensor, governor solenoid and governor itself. the Pressure sensor is also known as the transducer right? this is most likely the failed part instead of the Governor solenoid? i found the pressure sensors available online.

this is it, right?
Dodge, Jeep governor pressure sensor 1996-98, Transmissionparts usa.com

[Dano Moparo]

First off, it's prob in limp mode. Thats why you have weird acceleration. Just about 99% of all Chrysler trannys have been replaced within the first 36k miles. So I'm sure yours needs to be flashed or needs the new sensors or both.

Second I don't know, and I don't think anyone that I work with could tell you the values of the line press and voltage that your are wondering about.

Third, Yes your description of a transducer is correct.

Item #24 is the pressure sensor trandsucer, and item #29 is the transmission govenor solenoid.

[flubyux2]

well i appreciate all your help thus far.

regards
chris

[Dano Moparo]

np, I hope this helps, and I wish I had more information for you.

[flybyuin2.2]

I would replace both, the pressure sensor and solenoid, it is a very common problem and should be replaced every 50-60K miles to prevent premature failure, I highly recommend replacing the tranny filter too while you have the pan off.

[flubyux2]

Dano, you helped immensley. i went to a local tranny shop that was recommended to me. i had $50 in a diagnostic/inspection. they confirmed my suspicions. the voltage offset was too high because of a bad pressure sensor/transducer. the shop owner's son also said they replace both the sensor and the gov solenoid because they work hand-in-hand. they wanted a little over $300 to do the work. i told them that i do all my own work but i just needed a 2nd opinion. they put a new gasket on and new fluid in the truck, sold me the 2 parts and sent me on my way after a $280ish bill. i saved about $100 in shop labor doing it myself. took me about 2 hours at a slow pace and being anal about cleaning the pan, magnet and tranny gasket surface. the shop also noted that there was minimal clutch lining/peach fuzz in the pan upon inspection.

long story short, i replaced both of the governor components like we had suspected initially. i got all my forward gears back and the truck drives great!

im still giong to take my truck to the Crystal dodge dealer because there is a recall on my throttle linkage, so hopefully they will tell me all is fine w/ the truck then too.

[Dano Moparo]

Awesome