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Automotive/Nissan Altima 3.5SE Automatic Transmission Problem

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Expert: - 3/5/2008


Question
Hello Ernie,
I have had automatic transmission problem with my Nissan Altima eversince I bought it new in 2006.  The problem is abrupt/jerky shifts between gears, especially gears 1-2 and 2-3. It jerks both in the upshift and the downshift especially when you are around the transition speed for those gears and while accelerating / decelerating slowly (a usual situation in city driving).  The problem varies slightly with temperature.  I have been to 3 Nissan dealers, all of whom fail to recognize the problem.  I am a very car caring driver and very particular with standard maintenance. The car has 21000 kms on it and is still within the warranty period (but will expire by next yr).  Could you please tell me what may be causing the problem (could it be one of the sensors?)? How could I convince Nissan of the problem without waiting for it to get worse or running past the warranty period?  Your advice will be much appreciated.  Thank you.

Answer
Sorry to delay my answer; my workload is especially heavy now, as midterm approaches.

Paying attention to one's vehicle is something that too few people appear to do, so know that I am fully sympathetic with and supportive of your cause.  It is evident that you are motivated to take care of your machine and investment, to perform the needed preventative maintenance, and to exercise due diligence in checking things out when you perceive a problem.  This is inarguably a good approach!

Normally, a good suggestion would be to get a second or even third opinion, if one shop does not appear to recognise the problem.  However, you have that covered too, having seen three dealers.

That could suggest an unusual problem, possibly with a sensor or other anomaly in the electronic controls, as you suggest.

However, sharp shifts in an automatic transmission often are not a bad thing.  In fact, it is generally the case that transmissions that shift aggressively - positively, to put another term to it - suffer much less wear than do those which shift "smoothly", if the latter is indicated by an apparent "sliding' from one gear to the next.  Fast and positively-acting actuators do not dwell on the drums while the pressure is increased or reduced, and thus do not begin to scuff during the transition; they positively and quickly move from one gear to the next.  This is one reason for the existence of performance "shift kits" for many popular older transmissions, many of which were calibrated at the time of their manufacture to appeal to those wanting a smooth and seemingly effortless (while being anything but!) ride.

And so, I pose this just as a thought, based only on your brief but well written note.  Nonetheless, it is only you and your own experience that will count, and if it is your opinion that your car is shifting in a manner that is questionable, then keep after Nissan!

Good luck, and sorry again for the delay!

Regards ... EGK  

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Ernest (Ernie) Kenward

Expertise

The challenges I most enjoy are thoughtful technical questions of a trouble-shooting nature in both electrical, power electronic and mechanical systems, mainly automotive but also machine control and small-machine PLC applications. Please note, however, that I am NOT a walking shop manual! I DO, however, make it a point to have those manuals and other service literature for those vehicles I DO own, and highly recommend that anyone serious about maintenance or modification of their vehicles do the same; MOST of your answers WILL be found there. For that matter, I do NOT go out of my way to acquire shop manuals for any vehicle I do NOT own! That being the case, any general query to me along the lines of "What is the meaning of this code read from the ECU of my 2015 XYZ?" or "Where is the fuse for the windshield washer pump found?" (try your car's electrical distribution panel for a start!) will not go far. What I do offer is a pretty good collection of literature, insights and hands-on experience with 1950s to 1980's Ford products (plus a developing database of information and practice with the Mercedes diesel cars), along with an engineering perspective and the ability to design and implement custom control, electrical and mechanical subsystems for vehicles. For that reason, I am happy to make my thoughts and efforts available to those who are of like mind and/or are seriously making a point of learning about their vehicles. Use the Opportunity to Learn!

Experience

A key skill in my work and hobby pursuits both is STRATEGIC TROUBLESHOOTING. I am a senior instructor in Electrical Engineering Technology at a leading Canadian polytechnic, my areas being Electrical Power and Industrial Control, electrical and electronics design and manufacturing, and AutoCAD and related CAD/CAE software - plus equipment problem-solving and new equipment design and prototyping. Hobby-wise, I have 30-plus years of experience in auto restoration, mostly in electrical and mechanical systems. Ongoing projects include a 1959 Edsel Corsair, my 1978 Ford E250 class-B motorhome conversion, and the care and upkeep of my Mercedes 300CD. My vehicles become engineering test beds for electrical and mechanical upgrades as ideas present themselves. This includes the design and production of circuit boards to restore or enhance features for which no OEM replacement parts are obtainable, or where better specifications or reliability can be had via newer concepts. Regarding the E250 RV conversion, I designed and continue to revise a custom power distribution system, managed by a Programmable Controller (PLC); this has made most revisions as easy as uploading new firmware as I develop it. The "mini" PLC is a powerful device for custom automotive control systems. One good example (there are many) would be the Moeller "Easy Relay"; these offer a wealth of control, monitoring and variable-and-status display options for such projects. A good example project which has worked well is that one for my RV noted above, which has been on the job - revised in firmware only - for a decade now. It is a load management and charging control system to avoid the sulfation-induced early failure that often befalls deep-cycle batteries used in RV power applications. The battery installed in 2003 lasted long enough to more tnan pay for the PLC that contributed to its longer life ... and the PLC will be there for the next battery as well!

Organizations
IEEE - senior member ... past WCC Student Activities; SME - senior member ... past chair, greater Vancouver chapter chair 318; Edsel Owners' Club - have served in various capacities on chapter executive during seventies; have been Power and Driveline resource on the Edsel Owners' Club "E-team" for more than a decade.

Education/Credentials
Graduate of UBC

Awards and Honors
Certificates of appreciation from IEEE and SME for work in student and chapter activities

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