Engine/Transmission (1994 - 1998) tach and lock up problems

[ATorres]

Whats up everybody. I got a 1995 2500 with 169k on the clock. the tach works on and off, and the converter locks and unlocks whenever it wants. I can be cruising at any speed over 45 mph and when i give it throttle it locks up right away as soon as i coast it unlocks but it never holds actually it spends the majority if the time unlocked. Any help goes appreciated thanks

 

[Joe G.]

I don't know about the tach problem, but would check the crank sensor on the front of the engine just above the crank pulley.

Stock behavior for torque converter lockup is that when you lift it will unlock after a few seconds. That's why an exhaust brake won't work without some wiring modifications.

 

[Kirwin]

Tach problems and other stuff

Read my posts in the 911 forum under "acceleration shudder" for a discussion of the Throttle Position Sensor (TPS) and its effects on the torque convertor clutch. The crank sensor does many things for your vintage truck. It supplies the engine speed signal to the PCM. Now the PCM does very little to directly control the engine itself, however that being said: among othere things, the alternator will not work, as well as the tachometer if it doesn't see engine RPM. An intermittent tach is a sign that the RPM sensor which reads the slots off the vibration dampener on your model year truck has issues. The connector is at the top of the block next to the thermostat housing. Sometimes the insulation wears through so check the routing to the sensor wiring. The gap is critical and usually around . 050" and is supposed to be set with a non-magnetic feeler gauge. Hope this helps. Ken Iriwn

 

[ATorres]

I've replaced the engine speed sensor and still have the same problems no tach and int. lock up. Basically the converter wont stay locked. I did notice that my truck has a draw tite brake assist on it when i bought it, and it seems to be tapped into the brakes somehow but im not sure if this could cause any of my problems. ??? any help anybody im going crazy!

 

[Dieseldemon]

Does it unlock under power? if not like JoeG says that is the nature of the beast.

 

[LandShark]

We need more info to help you. What codes are you getting?
Does the 'wait to start' light work normally?

If the ESS is bad, lots of things will not work, including: AC, tach, overdrive, converter lockup, alternator and cruise control. These are all controlled by the PCM, but need the signal from the ESS to the PCM to work.

 

[ttbird]

I finally had my TPS go bad on my 95. Jumping in and out of OD and lockup. Was not willing to spend 100. 00 plus on the part. Replaced it with a linear potentiometer kit from DNR Customs which was alot cheaper. Now I can control lockup and OD myself. It's been one of the best things I've done to my truck. Here's the web site, check it out. 1st/2nd Generation Dodge TPS Delete Kit *91. 5-98 12v* [DNR] - $39. 99 : Zen Cart!, The Art of E-commerce