Powertrain Pro

  • A shudder type of a feeling may be felt during a first to second shift transition. 
  • The negative effects inconsistent tire size can have on transmission shift scheduling had been mentioned, particularly with BMW, Land Rover, Dodge and Nissan Maxima vehicles.
  • To diagnose a transmission with an intermittent shift shuttle complaint by the driver (3-4-3-4-3), only to discover that the problem occurred when the driver’s cell phone rang.
  • Sitting on top of the valve body are two revolution sensors mounted and connected to the TCM circuit board (figure 1). The sensor most forward to the front of the vehicle is called the Turbine Revolution sensor 2.
  • Toyota and Lexus vehicles equipped with either the 4 speed front wheel drive U140/240 transmission or the 5 speed front wheel drive U150/250 transmission may exhibit a loss of high gear.
  • With the RE5R05A transmission being used in vehicles with engine sizes as low as 3.5L to as high as 5.6L, the transmission comes in several different gear ratios.
  • The rear wheel drive five speed transmission known as the RE5R05A (Figure 1) is used in both Nissan and Infiniti vehicles as far back as 2002 to present time.
  • GM’s 4L60-E, 4-speed longitudinally mounted transmission with a strength rating of 60, was designated with an E to indicate that it is electronically controlled. 
  • The transmission makes a third gear start even though first gear is commanded.
  • Beginning at the start of production for 2009 model year, General Motors replaced the external NSBU switch with an Internal Mode Switch (IMS).
  • The 1-2 and 2-3 shift quality is poor, line pressure is within specs and the 1-2 accumulator assembly is correct for the vehicle application.
  • This month, let’s look at a case in which Diagnostic Trouble Codes (DTCs) P0716 and P0717 might be stored, there is no torque converter fill.
  • Mike Beglitsoff, owner of the Automatic Transmission Center in San Francisco, took in a 2003 BMW 325i with a ZF5HP19 transmission stuck in 4th gear only failsafe.
  • A recent transmission by Ford to hit the streets is an upscale version of their 5R110W transmission called the 6R140W. This transmission is also referred to as the Torqshift 6.
  • Sometimes after rebuilding a 4F27E/FN4A-EL transmission, an intermittent P0721 Output Speed Sensor Fault suddenly appears with no drive-ability complaints.
  • Customers who own a 2009 to 2011 Ford Escape or Mercury Mariner using the 6F35 front wheel drive transmission might complain about a hoot type noise.
  • I recently diagnosed the cause to a vehicle’s electrical problem in a relatively short order of time. I am not patting myself on the back as to how quickly I nailed it, but rather how easy it was to diagnose it.
  • Audi say its S6 vehicles using the ZF6HP26 transmission (Figures 1 and 2) have a noise they describe as being a “grunt.”
  • I must say that as nice as silver bullets are (and understandably so), there is a down side. This can and may dull ones diagnostic skills, encouraging pattern failure repairs.
  • It is very common to hear of gear ratio errors and shift complaints with Mitsubishi’s 4 speed front wheel drive F4A50 series transmissions.
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