Strange transmission shift and a terrible sounding whirling noise!

[onyxjeep]

Hi jeeps
I've been doing my best to look after my old 96 4.0 ltr auto xj. I love her to bits but as of late I have had a terrible sounding whirling almost chain like noise coming from under the bonnet that I cannot pinpoint. It sounds terrible in idle but even worse when on light acceleration. I also just recently noticed my tranny has been not shifting into 2nd gear properly! Almost seems to skip it but drove today and all seems fine again! I don't think the two problems are linked but does anyone have any ideas. I have tried all the obvious stuff like fluids and etc.
Thanks heaps!

[ApacheResistance]

Personally i'd test the TPS. It's directly related to transmission shifting.

Might sound like a longshot, but i'd hate for it to be something simple like that.

[Dustbowl]

Apache is right, its a TPS.
It should sound more like a turbine right? It's the torque converter locking up.
Upon failure the tps will create a "hard transmission fault" which is your shifting woes.
Does your air con work? :D

[ApacheResistance]

TPS TEST

The TPS is mounted on the throttle body. The TPS is a variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents throttle blade position. The sensor is connected to the throttle blade shaft. As the
position of the throttle blade changes, the resistance of the TPS changes. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.

The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. It is best to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. This will vary in an approximate range of from .25 volts at minimum throttle opening (idle), to 4.8 volts at WOT wide open throttle.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.


The TPS is sensitive to heat, moisture, and vibration, leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced