Engine/Transmission (1994 - 1998) -looking for technical auto trans trouble shooting steps.

[budnate]

guys I read for hours last night on old posts... . no where did I hit a good technical read on trouble shooting the electrical side of the 47RE in my '98 12valve.



there must be step by step checks a tech does on the electrical side of one of these, so your not a parts changer... anyone have a old link I missed.

my haynes manual does not cover it...



what I am trying to sort out is, my trans seems to be hitting all gears clean but my converter is not locking up under normal driving if you lift off the pedal to almost NO pressure, Idleing. . on it like coasting it will lock up... apply a little throttle to stay going and it unlocks.



fluid is clean, I plan to service the filter and adjust the bands next, the TV cable was adjusted by a friend who is Dodge tech I am 99. 9% sure it is done right. truck also has a new TPS switch.



it seems to me something is adjusted wrong or reading the wrong voltage at light throttle?... will a plug in diagnostic tool tell me if the voltage is wrong in or out at any of the elec gizmos in the trans?... .....



this is a new used truck to me so I am not clear on its history, the trans has been out for sure and rebuilt by who? what was done? it shifts clean and firm just not locking up right.



HELP... .....

 

[DFerverda]

I believe a 98 12 valve has a 47 RH transmission in it. The Rh works off vacuum and not so much electronic. I would search RH.
Dirk

 

[budnate]

ok. . newbie 47 question how do you tell them apart??



trim tag calls out a "DGB" standard duty auto"

 

[Joe G.]

I believe a 98 12 valve has a 47 RH transmission in it. The Rh works off vacuum and not so much electronic. I would search RH.
Dirk

NO!!! The 47RH was only used for the '94 and '95 trucks. The '98 has a 47RE. The 47RH does not work from vacuum. It has a fly weight governor to control governor pressure. The 47RE does that with a solenoid.

A factory service manual has trouble shooting for the automatic transmission. You can get one at Geno's Garage. Paper or CD. CD is a lot cheaper.

 

[budnate]

Thnx Joe... I was kinda hoping with this great forum this had been covered before in detail... my wallet is hurting about now from going through this truck front to back getting it ready to drive for awhile again, this is my last thing to sort out on the truck.



peace,B.

 

[fox]

The best manual to have is the factory service manual. There is nothing missing from it. Geno's should have them.

 

[fest3er]

Throttle Position Sensor (TPS) is the first thing to look at; it's the origin of the on/off idle signal. Odds are pretty strong that this is the problem. It's the plastic thingie near the front of the P7100. My '98's got similar problems; but I'm still using the original TPS and have only sprayed it out with elec. contact cleaner once in the 11+ years I've owned the truck.

 

[Joe G.]

You might want to read this thread:
https://www.turbodieselregister.com...mission-1994-1998/156901-tps-myth-buster.html

 

[budnate]

read all the TPS posts, my original tps was not providing the right voltage at idle so I hogged out the holes and twisted it to get 6. 77 at idle then drove it, it made O/D fine after that, I have to work today and have class tomorrow to renew a lic for work, I am going to varify my voltage's with the new tps from idle to full stroke on sunday



I did not notice the converter problem during my short test drives as

I had a major oil leak to deal with before driving much more than around the hood, long story short the KDP got the gear case and the last ahole patched it with jb weld and traded it in... along came me and drug this beast home to fluff up and run as my truck... been a major wallet shot sorting it out a tad more than I figured after my intial test drive and purchase.



oh. . one other thing to throw out is this truck has 285 65 16 tires the dealer threw them on before I came along... I dont think they fixed the speedo I am pretty sure it's off about 3/5 mph on the freeway... ... I read last night where some guys were claiming the puter could be reprograhmed to read correcty... . but when I got to the end of thread the guys dropped the ball and never said for sure one or the other if they were able to use the dealers prograhmer and make the tire size correction..... any feedback on this would be nice. fyi, this 12v truck does have the ABS system.



Thnx guys, B.

 

[Missouri Mule]

In the 96 service manual it states "The torque convertor clutch engages in fourth gear, and in third gear when the overdrive switch is Off. Engagemant occurs when the vehilce is cruising on a level palne after vehicle has warmed up. The torque convertor disengages when the vehicle begins to go up hill or the accelerator is applied. " This for 47re which you have in your 98.





I believe on a 98 you can adjust tire size at the PCM the vehicle speed sensor was moved to the rear diff in 98. If you don't have the VSS on the diff and it is still on trans(2wd) or transfer case(4wd) you will have to change out a gear inside trans/transfer case.

 

[budnate]

ok, another newbie question, where is the sensor on the rear mounted to read speed?? I took a quick glance last night and nothing is by the Yoke... is it Internally? off to class I will check in later.



Thnx B.

 

[DavidC]

ok, another newbie question, where is the sensor on the rear mounted to read speed?? I took a quick glance last night and nothing is by the Yoke... is it Internally? off to class I will check in later.



Thnx B.

The trans. speed sensor is just forward of the trans. mount on the drivers side. I ohmmed mine once and it showed open, picked up a new one at Auto Zone and ohmmed at 600. I really did not notice any difference in the trucks performance after the change as everything still worked the same as before. Maybe something on mine with the DTT and the smart controller negates that sensor.



Dave

 

[Joe G.]

It's on the back of the transfer case for a 4X4.

 

[budnate]

thnx guys just back from school got my ecu's so lifes good, burnt out tired, the gods are likeing Seattle today, dang sun is out and it's NICE!... Miller time and pool party! I will check in tomorrow after some testing.



thnx B.

 

[budnate]

found the new TPS bolted in the stock position was providing 2v's at idle position this morning . . WTF! bummed me out, you would think a brand new unit would not need to monkey'd with, oh well ... grabbed my old one that has hogged out mounting holes and I needed one so I could rotate it ...



set per Geno's tech on TPS set the voltage to 1. 2 and it stayed close to that after cycling the throttle a bunch..... took it on the freeway, of course it was packed so I could not get a nice test going without braking... but the converter acted the same not locking up.



a local member let me look at his manual so I have some reading to do and more testing... ... it also wants to start out like in 3rd gear?... so I slide the selector to 1st and it will take off OK and make all gears clean... . I am wondering if the pressure governor is causing these symptoms... made a few stops on the way home, come out hop in the truck and take off and it shifts great to O/D... . the longer I drive the more weird it gets, hot?.



also I plugged in a ODB II on the way home at Schucks the only code was "to high of TPS voltage"..... kinda threw me as the bulletin said shoot for 1. 2 to 1. 5v..... I was well within..... I double checked my voltage at idle when I got home and the tps had slipped? a little and was reading . 780... . not to Geno's spec but still within factory specs... ... more head scratching.



anyone done there home work on Governor solenoids? and found a new good one reasonable??? I was told the factory units even new are crap?



Peace.

 

[San Felipe Bob]

Yikes

I'm having the same exact problem.

The FSM states there are 4 things that control the lock up.

One of which is the temp senor located in the gov pressure sensor.

As well as the Gov pressure sensor itself.

Also the TPS.

I may attempt to wire in a resistor in the temp wires.

My trans runs cold and that might be part of the problem?

I think I will triple check the wires going into the trans.

Then I'll drop the pan and check those wires.

If you find the problem with yours be sure to let me know . .

Thanks

SFB

 

[budnate]

just got off the phone with my trans guy, he is slammed and said to change out the gov solanoid and gov sensor... adj the bands and see if it works, as thats where he would start before we rip it out, he cautioned me on the china solanoids there a 50/50 shot of being good right from new and had issues with new ones last week, sucks to be us right now.



B.

 

[San Felipe Bob]

gotta love it!

Well if it starts to look expesive I'm cutt'n the wires to the PCM and ordering a full stand alone valve body and trans controller from ATS or ?... .

Let me know what you find out with the gov. parts...



thanks

SFB

 

[San Felipe Bob]

I Know what the problem is!

It's this darn Cummins motor!

Any other truck would be sent to the scrap yard after 200,000 miles.

I've got 310,000 miles on it and all it has ever done is wear out the rest of the truck. #@$%!

If they could only build the rest of truck to last as long as the mighty Cummins!



I should have bought a different brand truck so I could be driving a new one every 100,000 miles... .





Cummins fan for life!!!



SFB

 

[GrantP]

I was having similar problems with the converter locking/unlocking at highway speeds. Heavy throttle it would stay locked, lighter "cruise" throttle would lock/unlock repeatedly. I just replaced the TPS 2 years ago which fixed my problem at the time, but I figured it hadn't gone out again that quickly. Per the FSM, I checked the throttle linkage and found it was a little over an 1/8" out of adjustment. After I fixed that two weeks ago the problem has not re-appeared. Just something else to check... and it's free.