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-   -   02 JGC Limited Erratic Shifting Tranny (http://www.jeepgarage.org/f203/02-jgc-limited-erratic-shifting-tranny-34390.html)

Fuzion 01-20-2012 08:44 AM

02 JGC Limited Erratic Shifting Tranny
 
Ok some of you know i have been having getting my jeep ready for the road with a new motor swap since Nov. I had a rod knock in the original motor so i replaced the motor with a 2003 4.7 w/60k with paper work and it went fine but all the sensors had to be changed because the motor was running weird. So after the sensor swap she runs good until she warms up.

Current Problem:
i picked up the jeep last-night from Steve @ Extreme Jeeps and everything's looked good for a Salvage yard 6 month warranty motor. I was driving on I95N and after about 15-20 mins the jeep would down shift to 3rd or 2nd i dunno which gear it was. At 50-70mph the RPMS were @3000-4000rpm so i just did about 50mph and limped it home. It was shifting back and forth up shifting down shifting like crazy. I would floor for a quick second and it would shift to the right gear then 15 secs later same thing happen. Now when pulling onto my street it was jerking hard when i left off the gas and then starting bucking like it was having a hard time shifting up and shifting down.

What I also noticed:
My mph was saying 20-30mph when i was going 45+, then as i said i would floor it for a quick sec and then it would read the mpg correctly and drive normal for 15-30secs MAX. I have NO CHECK ENGINE LIGHT AT ALL AND NO TRANS TEMP LIGHT WHAT SO EVER. Just because of the MPH being off, Im thinking some kind of speed/tranny shift sensor thinking its going that slow so its trying to select the appropriate gear for the MPH its "sensing". Also my rear passenger wheel speed sensor is bad, i had the code read because i have an AIR BAG light and an ABS light on (been that way since day one). Also when i stoped at the gas station the it was idling at 2k then gradually when down to 800-950rpm where it should idle at.

What do you guys think the problem is? I haven't checked the fluid yet but im going to do that this evening. Any other tips and tricks you guys recommend? Also i need to get a keyless enty remote. Thank you ahead of time for your help, its greatly appreciated.

Tamarr

Amelie 01-20-2012 08:48 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
Quote:

Originally Posted by Fuzion (Post 556551)
Im thinking some kind of speed/tranny shift sensor thinking its going that slow so its trying to select the appropriate gear for the MPH its "sensing".

That's what I'm thinking as well. I just recently had to replace both my Governor Pressure Senor and Governor Pressure Solenoid because my Jeep was having that erratic shitting as well.

Fuzion 01-20-2012 09:07 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
Quote:

Originally Posted by Reichminister Goebbels (Post 556553)
That's what I'm thinking as well. I just recently had to replace both my Governor Pressure Senor and Governor Pressure Solenoid because my Jeep was having that erratic shitting as well.

how much did that run you in parts? What was the labor? How difficult was the install? Would the parts you mentioned have the symptoms i was experiencing?

Amelie 01-20-2012 09:23 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
I think both the parts were $100 a piece. I'm not sure of the labor as my father was the one that dealt with whole ordeal.

Here's a write up of a dude who had to replace his.

http://www.jeepforum.com/forum/f310/...te-up-1182260/

Frango100 01-20-2012 09:32 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
First of all, which engine/tranny combo you have? The 42RE and 5-45RFE trannys have different components.
On the 5-45RFE, many shifting problems are caused by faulty input/output speed sensors or or a faulty TPS sensor (even without any codes)
Just re-reading your post, most probably your TPS is the problem, because of the high idling speed you encountered.
The vehicle speed is taken from the wheel speed sensors and when im not wrong the aft ones only.

Fuzion 01-20-2012 10:04 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
Body Style:
WJJP74
In-Service Date:
February 2, 2002

Engine:
EVA-4.7L V8 Power Tech Engine
In-Service Odometer:
7 Miles

Transmission:
DGQ-5-Spd Automatic 545RFE Transmission
Odometer Type:
Miles

Color 1:
PDR-Graphite Metallic Clear Coat
Car Line:
Z

Color 2:
QDR-Graphite Metallic Clear Coat

Frango100 01-20-2012 10:29 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
I would start changing the TPS, this is most probably your problem.

Fuzion 01-20-2012 10:57 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
ok will do along with a tranny flush and service....should i service the front and rear diffs also?

Fuzion 01-20-2012 10:59 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
Quote:

Originally Posted by Frango100 (Post 556568)
First of all, which engine/tranny combo you have? The 42RE and 5-45RFE trannys have different components.
On the 5-45RFE, many shifting problems are caused by faulty input/output speed sensors or or a faulty TPS sensor (even without any codes)
Just re-reading your post, most probably your TPS is the problem, because of the high idling speed you encountered.
The vehicle speed is taken from the wheel speed sensors and when im not wrong the aft ones only.


you mean use only the dealer speed sensors or aftermarket only?

cheapjeep 01-20-2012 11:19 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
Quote:

Originally Posted by Frango100 (Post 556597)
I would start changing the TPS, this is most probably your problem.

X2

Fuzion 01-20-2012 11:29 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
do i gotta take the airbox off etc..to get to it?

Fuzion 01-20-2012 11:29 AM

Re: 02 JGC Limited Erratic Shifting Tranny
 
Quote:

Originally Posted by cheapjeep (Post 556619)
X2


should i get the dealer part or any autozone pep boys parts place is fine?


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