I've read a number of TCC posts to the forum, but none that sound like my problem. . . First: 1998, 5.9L, 46RE 4X4, no mods, 208K miles.

For the last year, while at highway speeds (60+ mph) the torque converter clutch appears to intermittently slip (engine rpm rises without change in road speed). If I lift the throttle for a moment and re-apply, the TCC engages without slipping. Then, a few moments to sometimes minutes later it begins slipping again until I repeat the throttle lift/reapply technique.

Interesting observation: Last week I disconnected the negative battery cable for about 30 minutes to perform unrelated maintenance. The TCC slipping is very consistent, however on my first drive I noticed that I did not have any TCC slipping. This continued for the entire week until this afternoon when the problem appeared again.

The MIL is off, and there are no stored codes.

Not sure if it is worth noting, but usually when I lift the throttle at highway speeds, the instantaneous fuel economy display shows between 45-60 mpg. But, after disconnecting the battery and reconnecting, the first few drives actually produce a complete fuel flow cut when coasting (99mpg) - which is what I would expect. After a few drive cycles, the vehicle no longer coasts at 99mpg. This has been consistent almost as long as I've owned the vehicle (almost 14 years now).

Considering that when I disconnect the battery (and thus power to the PCM), and reconnect, all of my problems seem to disappear for a short spell. Does any of this suggest a possible PCM failure? Does a failing PCM always throw a code, or could I have a failed PCM component that won't store a code?

Thanks for the help.

 

It sounds to me like you have an issue with your lockup solenoid. Also, as for the instant MPG display, it is about worthless and is usually far from accurate.

 

the computer NEVER completely cuts fuel flow in these trucks, it limits it ALOT when coasting, or under what would be engine braking conditions with a manual, but it is always using some fuel.

 

After reading more about the fuel management (specifically fuel trim) of these engines, I think I understand why I see a difference in fuel economy and coasting behavior after resetting the computer. I'll save the pontificating since I no longer think this is related to my problem.

The obvious answer (lockup solendoid) may be the right answer, but how do I test for this without replacing parts. I also read that the low pump pressure due to pump bushing wear could also cause a similar symptom.

I'm having a hard time matching a diagnosis because of:
1. Intermittent behavior (it DOES lockup completely in many cases)
2. The apparent link to PCM power cycling (the problem goes away for a week when the battery is disconnected (or the ASD fuse is pulled). Over the past 9 months, the problem occurred EVERY drive, and after power cycling the PCM, the problem didn't occur again for more than 15 drive cycles.

What else can I check for or test before drilling down to the solenoid or TC replacement?

 

get in touch with master Tech, he is a dodge transmission tech and will be able to give you the troubleshooting/diagnostic steps you need, or tell you if its possible to test further w/o the scan tools

 

Do me a favor and replace the TPS. That will cause intermediate TC lock and un-lock especially in Overdrive. RPM's will fluctuate 100-300 RPM with no change in throttle position, exactly what you are referring to as I see it.

 

Here is a TSB. That may help. Its for the 2000 and 2001 durango, but its the same transmission.

SUBJECT:
46RE Transmission MIL Due To DTC P1740 – TCC or OD Solenoid Performance
OVERVIEW:
This bulletin involves the replacement of the transmission pressure boost valve cover
plate.
MODELS:
2000 - 2001 (AB) Ram Van
2000 - 2001 (AN) Dakota
2000 - 2001 (BR/BE) Ram Truck
2000 - 2001 (DN) Durango
NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A 46RE
TRANSMISSION BUILT BEFORE AUGUST 01, 2000 (MDH 0801XX).
SYMPTOM/CONDITION:
The customer may complain of a Malfunction Indicator Lamp (MIL) illumination. Upon
further analysis, it is determined that the MIL is caused by Diagnostic Trouble Code (DTC)
P1740 - Torque Converter Clutch (TCC) or Overdrive Solenoid Performance. Other than
the MIL, the customer may not notice any other condition with the transmission.
This condition may be caused by an intermittent and momentary TCC disengagement
condition. The transmission valve body pressure boost valve cover plate has been revised
with a larger size orifice hole to address this condition.
DIAGNOSIS:
1. Warm the transmission to normal operating temperatures.
2. Using the DRB IIIÒ, perform a torque converter clutch (TCC) stall test. The stall test
has been revised so that the TCC remains engaged for a period of four (4) seconds.
NOTE: THE DRB III MUST BE OPERATING AT RELEASE LEVEL 50.4 MDS2
SYSTEM CIS CD2067 OR HIGHER (AVAILABLE THE WEEK OF OCTOBER 2,
2000) IN ORDER TO PERFORM THE REVISED TORQUE CONVERTER
CLUTCH STALL TEST. DO NOT USE EARLIER VERSION STALL TEST TO
DETERMINE CONDITION OF THE TORQUE CONVERTER CLUTCH.
3. If the engine stalls as a result of the TCC stall test, then perform the Repair
Procedure.
4. If the engine does not stall, as a result of the TCC stall test, then further diagnosis is
required. The technician may want to consider the following components during
their additional diagnosis: a cut or worn input shaft seals, a missing pump lock-up
circuit check ball, or worn converter hub, input shaft, reaction shaft, and pump rotor.
This bulletin is supplied as technical information only and is not an authorization for repair. No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without written permission of DaimlerChrysler Corporation.
21-11-00 -2-
PARTS REQUIRED:
1 04617015 Plate, Pressure Boost Valve Cover (46RE)
1 02464324AB Gasket, Trans Pan
10(AR) 05010124AA ATF+3, Transmission Oil Type 7176 (2000 M.Y.)
10(AR) 05013457AA ATF+4, Transmission Oil Type 9602 (2001 M.Y.)
REPAIR PROCEDURE:
1. Clean the pressure boost valve cover plate to remove any dirt or rust inhibitor prior to
installation. The revised cover plate will have a 1.75 mm (0.069 inch) orifice hole
versus a 1.22mm (0.048 inch) orifice hole in the original plate. Make sure it is clean.
2. Using the appropriate Service Manual, Transmissions and Transfer Case,
replace the transmission pressure boost valve cover plate p/n 04617012.
3. Verify fluid level after warming up the transmission and cycling the shift lever several
times.
4. Verify, and if required, adjust the transmission shift linkage and the transmission
throttle valve cable per the appropriate Service Manual procedures.

 

The TPS is the first thing I swapped when this began occurring. No change. I saw that problem about 10 years ago and the TPS corrected the condition. Also, this is more than 100-300 RPM rise. It varies between "slipping" (partial engagement) and no apparent engagement at all (1500-2000 rpm rise).

master Tech - the TSB specifies vehicles with the MIL light on. I've never had a MIL light or a code related to the transmission. Do you still think the TSB is applicable? Symptomatically, it certainly sounds right - except for the MIL light and code.

Many thanks - this is good info.

 

Look at the build numbers on the side of the trans just above the pan. If it fits then fix.

 

I never figured out what was causing the intermittent and partial lockup issue, but I replaced the valve body with a rebuilt unit for $200 (ebay) and everything is working perfect again. Could have been solenoids, or internal seal wear, but for $200 the price was cheap enough to throw it in and toss the dice.

The only snafu in the swap was a park rod that was bent. I couldn't get the park lock pawl to engage, even with the valve body properly installed. When I compared them side-by-side it was evident that the bends resulted in a rod that was slightly different in length. A quick swap fixed the problem.

Back on the road. Thanks for all the help!