RPM's unsteady

[Xplorer95]

I have a '95 4dr 4x4 with 105k miles. When I'm driving, mostly insterstate, the RPM's will jump up about 300-400 and then go back down. I hold the gas pedal at the same spot, but it still goes. It's almost like its "trying" to downshift, but gets halfway there and changes its mind, or just can't do it...?? It's sorta like pushing the clutch in and letting it out, but this is an automatic. Someone told me it could be vacuum lines, but I can't find any problems. The check engine light is not on. What could it be?

 

[liqhx2]

sounds like the lockup tourqe converter is acting up

 

[Xplorer95]

anybody else?

 

[Glacier991]

What are the RPM's? It does sound like either the 3-4 shift solenoid or TCC lockup.

 

[Xplorer95]

The RPM's are anywhere between 2000-4000. I thought it was a problem with shifting between 3rd and overdrive, but it still did it when I turned overdrive off. I guess that pretty much means it is the TCC lockup? Whats gonna happen with this thing completely quits working? How much longer will it last? And how much will it cost to fix?

 

[TSTONE]

replace your throttle positioning sensor - cheap part to try - and most likely your problem

 

[Xplorer95]

How can I distinguish between it being the tcc or sensor?

 

[liqhx2]

have you gotten any flashing OD light at all?

 

[liqhx2]

Torque Converter Clutch Concerns: Cycling/Shudder/Chatter Possible Component Reference/Action
242 ?ELECTRICAL ROUTINE
Powertrain Control System
Electrical inputs/outputs, vehicle wiring harnesses, internal transmission wiring harnesses, powertrain control module, TCC, TR, BOO, TP, RPM
Perform TCC tests. Run on-board diagnostics. Refer to Powertrain Control/Emissions Diagnosis Manual for diagnosis. Using Rotunda Transmission Tester 007-0085C and Rotunda Transmission Range (TR) Sensor Adapter ("MLPS" Manual Lever Position Sensor Adapter) 007-0086A or equivalents, perform transmission static and dynamic tests. Perform the following Pinpoint Tests: C, D. Service as required. Clear codes, road test and rerun on-board diagnostics.

Speed control equipped vehicles
Evaluate with speed control off.
342 ?HYDRAULIC/MECHANICAL ROUTINE
Fluid
Fluid contaminated
Inspect fluid for contamination. If contaminated, locate source of contamination. If burnt, inspect mechanical band, clutches. Service as required.

Main Control Assembly
Bolt out of torque specification
Retorque to specification.

Gasket damaged, off location
Inspect and replace gasket.

Separator plate damaged
Inspect for damage, service as required.

TCC, solenoid stuck, damaged, O-ring damaged or out of bore
Inspect for damage, perform solenoid function test as listed in electrical routine. Service as required.

TCC solenoid and valve (200), converter clutch control valve (201), thermostat bypass valve/cooler limit valve (216), spring, damaged, missing, misassembled, stuck, bore damaged
Inspect for damage. If damaged, replace main control. If parts are missing, replace missing parts or main control. If misassembled, reassemble properly. Do not stone, file or sand valves. This will remove the anodized finish and may result in further main control or transmission damage.

Pump Assembly
Bolts out of torque specification
Retorque bolts to specification.

Cross leaks
Inspect for damage. Service as required.

Front pump seal damage
Inspect for damage. Service as required.

Seal on inner pump gear damaged
Inspect for damage. Service as required.

Torque Converter Assembly
End clearance (excessive), internal leakage, clutch material damage
Perform end play check. Inspect and service as required.

 

[TSTONE]

You may want to read my thread - I had a very similar experience.

http://www.explorerforum.com/forums/showthread.php?t=61909