Transmission Problem - J30T Sticks in Low Gear

[Puddles]

Hi, i've been having a minor transmission issue on my '94 J30T intermittently for a few months but suddenly today it got quite a bit worse. I've had this car since new and have always been good about maintenance. It has 68k miles.

The problem occurs when starting from a stop. It doesn't shift into a higher gear when it should, but instead it just revs faster and faster. Sometimes i can get it to shift by easing up on the gas and then it'll shift. For a while today i couldn't get it to shift no matter what i tried for about 5 minutes. I could only take it up to 30 mph because it was revving so high.

I wanted some advice before i take it somewhere for repairs. First, does this sound like a common or easily diagnosed problem...any guesses as to what it is? Second, i'm wondering if i should take it to the Infiniti dealer (i always take it there for 15k maintenance) or if any good repair shop should be able to handle this task?

I also should mention one other weird thing which seems unrelated but happened at the same time the transmission got worse today: I was driving and heard a big clank under the car and something fell off the bottom of the car. I went back and got it (other cars had flattened it by then). I'm not sure what it is but it looks sort of like a heat shield for the catalytic converter. It's about 12" x 10" with a number of 1/2" holes in it. Like i said, i don't think this is related to the transmission problem but i'm just not sure since it all happened at about the same time.

Thanks for any input!

Kurt

[driverdriver]

It could possibly your rev sensor. It could also be that your transmission is on its way out.

I would check the ECU for any codes.

What color is your transmission fluid? Has it been changed recently?

[Puddles]

Thanks for your reply. The 60k service was done 5 years ago (8k miles ago) by the Infiniti dealer. The invoice says "Complete ATF Replacement" and "Trans Flush Cleaner BG106". No problems were noted. The fluid today looks clear/red and smells fine.

Never heard of a rev sensor but it sounds cheaper than a new transmission!

The engine light is not blinking...could there still be a code in the ECU? I tried to locate the ECU ("The ECU is located behind the front passenger kick panel, located in the passenger footwell") but am apparently too dumb to figure it out. Is it behind the carpeting? On a side wall or rear wall of the footwell? I don't see anything and was worried about pulling the carpet off if i'm in the wrong area.

Still not sure who i trust to take care of this problem....Infiniti dealer, good local shop that does my oil, or a transmission specialty chain store....any opinions?

I have to say that this car is no Honda or Toyota. It has had too many problems considering it still has less than 70k miles. New air conditioner at around 50k was the worst, especially since it had been used a total of maybe 10 hours before going bad. When i bought it i assumed that all Japanese cars were equally good but my experience says otherwise. Not that 1 car makes a scientific sample....maybe mine is an unusual lemon.

Kurt
Modified by Puddles at 11:28 AM 8/17/2008

[Gerardjg]

Transmission Self Diagnosticsusing AT light below your temperature gauge on the dash

1-Warm up engine2- Shut off car and turn ignition switch to ACC position3-Wait 5 seconds4-Move shifter to D5-Turn ignition switch on do not start

AT check light should come on for about 2 seconds

6-Move shifter to 37- step on gas fully and release8-Move shifter to 29-Move shifter to 110-step on gas fully and release

The At Check light should start flashing a sequence of11 flashes aslight pause and start over again. All flashes should be the same length, any flash that is longer indicates a trouble the following list is what the trouble circuit or part is.

A longer flash indicates

1st Flash Revolution sensor2nd flash Speed sensor3rd flash Throttle position sensor4th Shift solenoid valve a5th Shift solenoid valve b6th overrun clutch solenoid7th tourqe converter clutch solenoid8th fluid temp sensor9th engine speed signal10th turbine revolution sensor11th pressure solenoid valve

[driverdriver]

I have to say that this car is no Honda or Toyota. It has had too many problems considering it still has less than 70k miles. New air conditioner at around 50k was the worst, especially since it had been used a total of maybe 10 hours before going bad. When i bought it i assumed that all Japanese cars were equally good but my experience says otherwise. Not that 1 car makes a scientific sample....maybe mine is an unusual lemon.

Kurt

Modified by Puddles at 11:28 AM 8/17/2008

Your J30 is 14 years old, regardless of mileage, things WILL break because of age. In the past I have owned Toyota's and Honda's with 8 or more years on them and expensive things break because of age or wear on the most relaible japanese cars. No car will be reliable forever. Regular maintenance/service history plays a huge factor.

[GerryO]

Check the voltage output of your TPS (throttle position sensor). Insert a strand of wire into the middle of the backside of the pull-apart connector to it, start the engine, run at idle (throttle closed) and touch the (+) probe to the wire and the other (-) to ground. The voltage reading should be between 0.40 and 0.45 VDC. An out of adjustment TPS won't trigger any codes either and would probably cause a high idle speed too.

Could also be a bad KS/connection (knock sensor), which won't trigger the CEL (check engine light) or any codes.

[Puddles]

Thank you. I tried that Trans Self-Diagnostics test using the AT Warning Light....no codes appeared, all 11 blinks were good...it's a cool test though.

I called the dealer and he said it could maybe be one of a couple sensors, or else it's probably a major problem requiring a $4000-$5000 new transmission!!! He actually suggested taking it to a trans specialty shop where they can rebuild if necessary because Infiniti can only provide a brand new trans.

You gotta be kidding me....$4-5k!! This car doesn't have a single scratch on the exterior, has never once been left outside in the sun, hasn't been driven in snow or rain or wet streets for over 5 years, etc etc. And now it is potentially junk?! Makes me wonder why i bothered taking such good care of it.

Today the problem has disappeared. The shops say they can't do much unless the problem is happening when i bring it in.

I'm just ranting....i do appreciate all the responses, thanks.

Kurt

[driverdriver]

If it appears and disappears I would hedge a bet its your rev sensor. Its what happened to me.

[Elisha]

Infiniti lies....they will only sell you a rebuilt. there is no brand new one for the J30 at this point in time or so about 8 dealerships said to me. i was in the same boat as you for a transmission replacement last year. all local dealerships quoted $3.5k for transmission alone. called Scottsdale Infiniti and spoke to Joe and he said they only order rebuilt too but if you sent them your old core, they will give you a rebuilt one for $1800.anyway if you get it rebuilt at a local shop, make sure the mofo's replace the rubber hose that runs to the long end of the rad as well.mine busted 1 week after the transmission replacement and now the car is in a salvage yard.

[yodawill2000]

OMG E.Maybe its because I'm a born and raised Texan but if that happened to me and they didn't replace the transmission that place would be burned to the ground with a quickness.That's just wrong.Dry rot hoses are easily identified.

[thomasso51]

Hey - I've had the same problem with my '94... the simple answer seems to be that it is the speed sensor, but, being far more of a bonehead than most on this site, I cleaned the MAF sensor (look it up on this site, simple as hell) and as a result my sticking in a lower gear has eased up about 90%. Still does it sometimes but well worth the effort. DO NOT buy a new transmission, if this doesn't work it's simply one of your sensors. We have a great group in Atlanta called T3 Automotive that specializes in Infiniti's.

[yodawill2000]

I sure wish there was a T3 near DFW.I have the utmost respect for Q45Tech and his plethora of Infiniti knowledge.

[Q45tech]

I cannot imagine a Nissan with 14 years on a automatic transmission functioning well even with only 84k.

Use the Consult [I, II, or III] to view all the electronic parameters in TCU and sensors.

Nissan reman AT run about $1750 [wholesale] with exchange and $600 to swap.

Luckily the RE4R01A is a common transmission [300zx, trucks, etc].

Many local shops can rehabilitate [not as well as Nissan factory] depends on whether you want: a year or 2 of service or another 7 years. You get what you pay for.

[coolyun_98]

I just love it when Q45Tech comes to our board...

Thank you Q45Tech, please come again!