How JustAnswer Works:

 
 
 
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
 
 
 
Ask CJ Your Own Question
CJ, Shop Foreman
Category: Jeep
Positive Feedback: 97.7 %
Satisfied Customers: 7690
Experience: ASE Jeep Master tech
Type Your Jeep Question Here...
CJ is online now
A new question is answered every 9 seconds

jeep: trans..gearbox output shaft sensor..rev

Resolved Question:

Hi chris,
im still having a problem with my jeep trans. I recently had a gearbox output shaft sensor changed, which helped a little, but to get it into overdrive on the road i have to really rev the vehicle quite high. once it goes into overdrive she goes beautifully, but the fault is so intermitent that im losing confidence in the vehicle. Most days are fine but every now and then it plays up. Any thoughts on what im missing? Someone suggested a solenoid in the gearbox thats measures the fluid pressure could be the fault, as its very intermitent and not a continuous problem. With your experience, does this sound a credible option?
Many thanks, Darren.

Submitted: 1 year ago.
Category: Jeep
Picture
Expert:  CJ replied 1 year ago.

Hello and welcome to just answer. This may be credible, but I am not completely sure. Let me see if there are any bulletins regarding this.

Chris

Ask Your Own Jeep Question
Customer: replied 1 year ago.

ok

Expert:  CJ replied 1 year ago.

Ok, your overdrive problem may be sensor related, or the PCM (engine computer) or TCM (transmission computer) may be seeing stray RF interference which may cause shifting issues. I recommend showing this Star Case bulletin to your garage or Jeep dealer and have them check some of the things out lined in this bulletin. Using a scan tool would be of great help in determining what is going on here.
I hope this helps, and let me know if you need any further assistance with this.
Chris

Case NumberNNN-NN-NNNN
Vehicle Issue Overdrive (4th gear) not shifting properly. Trans may be in limp mode.;Applies to rear wheel drive models with RH or RE type auto trans. No shift or improper shift from 3rd to 4th gear. Related trouble code may be set in powertrain control module (PCM).
System or Component Upshift / Downshift Issues;Customer Concern (No DTCs),DTC / Error Message;Automatic Transmission / Transaxle;4th Gear,3-4 Upshift;Yes - Intermittent,Yes - Continuously
Recommendation The PCM controls the overdrive 4th gear solenoid while monitoring various sensors. See recommended diagnosis / repair steps listed below. Repair as required. For improved diagnostic accuracy install the Co-Pilot tool to data record the condition. STEP 1): DIAGNOSTIC TEST: If trouble code is present see test procedure in the applicable Powertrain Diagnostic Procedures Manual. To test circuit wiring for high resistance suggest use headlamp or fog lamp to place load on the circuit being checked. Circuits with high resistance may illuminate a test lamp normally but a larger lamp will be very dim. STEP 2): BATTERY AND CABLES: Check battery condition and battery cable connections. Check main ground circuit for the PCM. Repair loose or corroded connections. If dual batteries are used verify batteries are properly matched and are in good operating condition. STEP 3): GENERATOR: Evaluate condition with generator wiring harness disconnected. Generator and/or generator wiring harness may produce excessive radio frequency interference (RFI). Excessive RFI can interfere with PCM input signals. If the condition stops insulate the generator wiring harness with tape or wrap that will prevent excess RFI (obtain locally). Replace generator if condition persists. MODELS WITH CUMMINS DIESEL ENGINE: Evaluate condition with fuel transfer pump electrical connector unplugged. Fuel transfer pump may produce excessive RFI. If condition stops replace the fuel transfer pump. STEP 4): PCM SENSORS: Check all related PCM sensor inputs. See list provided: [1]: Engine coolant temp must be above 120 degrees. [2]: Trans fluid temperature must be above 60 and below 272 degrees F. [3]: Vehicle speed must be above 32 mph. [4]: Trans must be operating in 3rd gear. [5]: Overdrive switch must be in the overdrive allowed position. [6]: Park / neutral switch signal to PCM must not be grounded which would signal trans is not in gear. [7]: Engine RPM signal from crankshaft position sensor (CPS) must not be erratic. [8]: Throttle position sensor (TPS) signal must not be erratic. Check signal from TPS or APPS. ERRATIC TPS SIGNAL: If TPS signal is erratic see list of possible causes: [A]: TPS circuit wiring / connector pin problem or TPS malfunction. : Worn or damaged engine throttle linkage or cable. [C]: Defective clock spring unit in steering column. [D]: Excessive radio frequency interference (RFI). Check for circuit wiring routed too close to spark plug wires. [E]: Check for electrical add-on equipment. Remove equipment if required and discuss with owner. STEP 5): OVERDRIVE PRESSURE: Check overdrive clutch apply pressure when 4th gear is engaged. This test will check operation of the overdrive solenoid and overdrive clutch seals. See test result suggested repair: OVERDRIVE PRESSURE TEST RESULTS: [A]: Pressure always zero: Check all related O/D solenoid circuit wiring and connectors. If no circuit wiring problems are found replace O/D solenoid on valve body assembly. : Pressure low: Remove overdrive unit and inspect. Check overdrive piston seals. Check for missing bleed orifice check ball in O/D piston. Check gasket between trans case and overdrive piston retainer. [C]: Pressure OK but overdrive will not engage: Check all internal overdrive unit components. Requires special tool for disassembly. Repair or replace O/D unit as required. END OF PROCEDURE


CJ, Shop Foreman
Category: Jeep
Positive Feedback: 97.7 %
Satisfied Customers: 7690
Experience: ASE Jeep Master tech
CJ and other Jeep Specialists are ready to help you
Ask Your Own Question Now

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
< Last | Next >
  • Thank you so much for your answer. My initial estimate was $325; I got it done for $100 - part and labor. Lynn B. Ormond Beach, FL
  • I was skeptical at first but thought I'd give it a try. I was pleasantly surprised. Your site actually is a quality service that I would recommend to others in a heartbeat. Stan Sayre, PA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
 
 
 

Meet The Experts:

 
 
 
  • Mark's Avatar

    Mark

    22 Year Factory trained technician

    Positive Feedback:

    98.6 %

    Satisfied Customers:

    2521
    Jeep factory training........25 years in the industry.
< Last | Next >
  • http://ww2.justanswer.com/uploads/MO/MoparCertified/2012-6-7_4142_mechanic.64x64.jpg Mark's Avatar

    Mark

    22 Year Factory trained technician

    Positive Feedback:

    98.6 %

    Satisfied Customers:

    2521
    Jeep factory training........25 years in the industry.
  • http://ww2.justanswer.com/uploads/jeep10000/2008-9-18_222938_192601.jpg CJ's Avatar

    CJ

    Shop Foreman

    Positive Feedback:

    97.7 %

    Satisfied Customers:

    2063
    ASE Jeep Master tech
  • http://ww2.justanswer.com/uploads/ke4ich/2009-08-12_212931_DSC02211.JPG moparfl's Avatar

    moparfl

    ASE Certified Technician

    Positive Feedback:

    98.2 %

    Satisfied Customers:

    1128
    ASE Master Tech Chrysler Dodge Jeep Master Tech
  • http://ww2.justanswer.com/uploads/nvltgo/2010-10-18_211525_youranswers.jpg Dave's Avatar

    Dave

    Jeep Master Tech

    Positive Feedback:

    97.6 %

    Satisfied Customers:

    1089
    Chrysler Triple Master, ASE master Tech AA degree in Auto.
  • http://ww2.justanswer.com/uploads/tsmodie/2009-6-10_144056_tim.jpg TIM MOHR's Avatar

    TIM MOHR

    ASE MASTER TECH

    Positive Feedback:

    97.4 %

    Satisfied Customers:

    754
    30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL
  • http://ww2.justanswer.com/uploads/zzdaryl/2008-3-26_193252_me.jpg zzdaryl's Avatar

    zzdaryl

    Shop Owner, Master Mechanic

    Positive Feedback:

    97.8 %

    Satisfied Customers:

    624
    28 years experience, Master Mechanic
  • http://ww2.justanswer.com/uploads/CD/CDJMastertech/2012-6-9_201455_JustAnswerProfilelarger.64x64.JPG CDJMasterTech's Avatar

    CDJMasterTech

    Jeep MasterTech

    Positive Feedback:

    99.5 %

    Satisfied Customers:

    576
    Factory trained and certified Jeep Master Technician, ASE Master Technician