Transmission Shifting from 4th to 3th on the highway.
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Joined: Jan 2013
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Model: Cherokee
Transmission Shifting from 4th to 3th on the highway.
I'm new to this forum, I started driving my jeep around after i wrecked my BMW 
shhhh dont judge!!
But anyways down to business...
I drive a 1997 Cherokee 4.0L
The issues however that I'm having are a bit strange, I'm very new to automatic transmissions and I need some help.
The Problem:
While I'm driving down the highway the jeep tends to downshift from 4th to 3rd, giving a bit of a jerk when it does it. It constantly does it back and forwarth shifting back into 4th then back into 3rd reguardless of the grade of the road. The problem ceases to exist when i drop the jeep into 3rd and it runs normally.
What's causing this to occur? It sounds like a sensor problem to me.
Now I did have a code fire up which pointed directly at my Neutral Safety Switch(NSS) - however with a little research I have confused answers out there with 3-4 different problems locations which could cause this. I'm going to take apart the NSS and clean it and reinstall it but will this 100% eliminate my problems?
Additional Information:
There was also random occurances where i started my jeep and it idled at 3.5k rpm and did not drop to 600 unless i drove it about 5 miles.
shhhh dont judge!!But anyways down to business...
I drive a 1997 Cherokee 4.0L
The issues however that I'm having are a bit strange, I'm very new to automatic transmissions and I need some help.
The Problem:
While I'm driving down the highway the jeep tends to downshift from 4th to 3rd, giving a bit of a jerk when it does it. It constantly does it back and forwarth shifting back into 4th then back into 3rd reguardless of the grade of the road. The problem ceases to exist when i drop the jeep into 3rd and it runs normally.
What's causing this to occur? It sounds like a sensor problem to me.
Now I did have a code fire up which pointed directly at my Neutral Safety Switch(NSS) - however with a little research I have confused answers out there with 3-4 different problems locations which could cause this. I'm going to take apart the NSS and clean it and reinstall it but will this 100% eliminate my problems?
Additional Information:
There was also random occurances where i started my jeep and it idled at 3.5k rpm and did not drop to 600 unless i drove it about 5 miles.
Last edited by nicholas.lopes24; Jan 7, 2013 at 12:24 PM.
Herp Derp Jerp
Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
If you have an NSS code definitely start there. Pretty common failure so it's not a waste of time either way.
You may be having TPS issues. First off try this: https://www.cherokeeforum.com/f2/free-quick-fix-41821/
Also check for vacuum leaks and test your TPS with an analog multimeter. You should have +5VDC going in on one pin, another pin will be the signal return to the ECU/PCM. As you work the throttle, the output on this pin should be a SMOOTH climb from approx 0VDC with the throttle plate shut to 4.5VDC wide open. Jerkiness is no good. Same for excess readings at any point.
You may be having TPS issues. First off try this: https://www.cherokeeforum.com/f2/free-quick-fix-41821/
Also check for vacuum leaks and test your TPS with an analog multimeter. You should have +5VDC going in on one pin, another pin will be the signal return to the ECU/PCM. As you work the throttle, the output on this pin should be a SMOOTH climb from approx 0VDC with the throttle plate shut to 4.5VDC wide open. Jerkiness is no good. Same for excess readings at any point.
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