1993 Infiniti J30 OD Shifts On and Off

[TexRodeo]

I have a '93 Infiniti J30 with now 135k miles. The Transmission was rebuilt in December of 2007. I bought this car back in late August of 2008 at like 124k miles. Well this past about a week my OD shifts strange around 40-50MPH. It keeps jumping from OD to 3rd and back again, almost like it cant seem to make up it's mind which gear to pick. I had read on the NICO site that the transmission should be serviced at 30k-40k miles, could this be a possibility? Please advise me further on this matter of what possible things I should or could try, I am On disability and really cant afford Costly repairs.

Larry Little
1993 Infiniti J30 (Base)
135k Miles

[yodawill2000]

I feel your pain brotha'
Start with checking your TPS.
A search on that here should pull many how too's.
Very simple if you have a consult and cable, but can be done at the TPS with a good ohm meter.

[TexRodeo]

yodawill2000,

Will that cause Shift issues with the OD? I have not gotten and Service engine Light or an A/T Check light illuminated at this point. But I will say with this thing not staying put in OD and shifting back to 3rd, it's eating the hell outta gas much more than it normally does. And that is a b**** with a car that has the natural mileage as the J30 and having to feed it Premium Gas that is really hard on my wallet.

I always thought that the TPS would cause issues with the idle control more so than with the transmission shifts. How would it cause or in what way would a malfunctioning TPS cause this type of shift issues? I am a PC/MAC tech not really an auto mechanic and don't have a great many tools to work on a car as well as I dont have acceess to Consult Code reader, Any Other ideas?

Larry Little
1993 Infiniti J30 (Base)
135k Miles

[yodawill2000]

http://www.wellsve.com/sft503/counterp_v2_i1_1998.pdf

[TexRodeo]

Yoda,

I appreciate that info. OK now is there a step by step procedure to replace the TPS on a '93 Infiniti J30?

Larry Little

[GerryO]

Here's some information that should prove helpful.

http://home.swipnet.se/e-solutions/IdleTech2.html

[yodawill2000]

Tex
All you may need is to adjust the TPS.
Not replace.
I did that about a year ago and it solved the problem until a month ago or so.
I think I have a different prob.

[GerryO]

A nice diagram, some descriptions and lists of transmission related inputs and outputs for another vehicle. I'd also include the Brake Pedal and Kick-Down Switches, and the MAF, if it's not covered by the Engine Vacuum Sensor.

An exact pin-point diagnosis of this issue will be golden.

[driverdriver]

Do you know if your transmission rebuild an Aamco style rebuild or an OEM rebuild or a rebuild at a JATCO certified shop?

I know from years of reading posts, that there are differences between transmission rebuilds as well as longevity differences. OEM and JATCO certified rebuilds are the most trouble free.

[1994 infiniti j30 190+]

Aamco style

All Automatics Must Come Out haha basically a crappy job unless you now someone there that will actually do a good rebuild

[TexRodeo]

I am Not Sure How it was rebuilt. I just know itr was done before I purchased the vehicle according to the reciept that was left in the Infiniti Leatherbound Folder in the glovebox. Anyways, I turned the TPS Clockwise and the transmission has started shifting fine. Everything seems to be back to normal. Thanks Yoda, I really appreciate it Buddy.

Larry Little
1993 Infiniti J30 (Base)
135k miles and all is well again!!!

[yodawill2000]

Cool Beanz !!

[driverdriver]

[swimshark]

hah i started reading this and hoped you werent having same problem i encountered. my trans died and it started with an issue similar to this. glad it was just the TPS being off.