tranny problems HELP!

[infinitiinfinity]

I have a 94 J30 and the transmission is rough shifting from 1st to second. It also feels like it is shifting back and fourth from 3rd to 4th gear on the highway for no reason sometimes. I had the fluid flushed and new filters put in and two weeks later the fluid smelled and it was dirty. The mech. said that there was metal in the tranny and it was going to have more problems. Can anyone tell me if they think it needs to be replaced? If so how much? Thanks

[Nahkapohjola]

Originally Posted by infinitiinfinity

I have a 94 J30 and the transmission is rough shifting from 1st to second. It also feels like it is shifting back and fourth from 3rd to 4th gear on the highway for no reason sometimes. I had the fluid flushed and new filters put in and two weeks later the fluid smelled and it was dirty. The mech. said that there was metal in the tranny and it was going to have more problems. Can anyone tell me if they think it needs to be replaced? If so how much? Thanks

On most models Throttle Position Sensor TPS is used in transmission control. More specifially: the pedal press down -speed is calculated, and based on that, shiftdown follows or not. Shaky TPS causes spastic output to TCU and thereby can cause phantom downchange.

This TPS is a potentiometer that wears down each time pedal is touched. Its worn already... Replace it to be sure; abou 90$, half hour works.

Another electronic error source is the TCU Transmission Contol Unit (computer) and its oxidized connectors. In any case, get them and all tranny connectors under hood cleaned. Bad TCU contacts result in too low controlling solenoid voltage. This causes slipping that wears the tranny down fast.

If tranny is mechanically worn, the electronic repairs will not help it, but surely increases the new tranny life 4x.

see: http://www.cardomain.com/my/edit_pag...748507&page=15
http://www.cardomain.com/my/edit_pag...748507&page=14
http://www.cardomain.com/my/edit_pag...748507&page=10


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[infinman]

First off shock shift 1-2, can be caused by either a bad dropping resistor allowing TOO MUCH voltage to shift solenoids or a broken 1-2 accumilator shift valve spring{valve body}.Second shifting in and out of gears highway.Common problem on J30's.What happens when starting from a stop is: shift: 1-2,2-3,3-overdrive,overdrive-torque convertor lock-up{engine and trans input at same rpm's}As long as you are cruising with accelerator on it will remain in tcc lockup.As soon as you release accelerator trans downshifts to overdrive.When you again accelerate, given the right speed it goes back into lockup.Try it on the highway.Get up to cruising speed then release throttle then right away return throttle.You will feel a bump when tcc disengages/engages.This is not severe and the fix is to replace the valve body.Very expensive.Metal in the pan?That is another story.

[infinitiinfinity]

Originally Posted by infinman

First off shock shift 1-2, can be caused by either a bad dropping resistor allowing TOO MUCH voltage to shift solenoids or a broken 1-2 accumilator shift valve spring{valve body}.Second shifting in and out of gears highway.Common problem on J30's.What happens when starting from a stop is: shift: 1-2,2-3,3-overdrive,overdrive-torque convertor lock-up{engine and trans input at same rpm's}As long as you are cruising with accelerator on it will remain in tcc lockup.As soon as you release accelerator trans downshifts to overdrive.When you again accelerate, given the right speed it goes back into lockup.Try it on the highway.Get up to cruising speed then release throttle then right away return throttle.You will feel a bump when tcc disengages/engages.This is not severe and the fix is to replace the valve body.Very expensive.Metal in the pan?That is another story.

what is that story, if you dont mind

[infinman]

Sorry for getting technical.Your transmission shifting is controlled by computer.You need to have someone scan the trans. control unit for proper inputs and outputs.If that checks ok you are in for a swap or overhaul.Don't know about prices in your area.

[Nahkapohjola]

Originally Posted by infinitiinfinity

what is that story, if you dont mind

...a story of electronbirdies: no way gettin anywhere 'overvoltage' that is more than battery Voltage... dont drive to such passing bird spots.

Healthy solenoids get 11-14Volts - Nissan FSM.

[infinman]

Quote:
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Originally Posted by infinitiinfinity
what is that story, if you dont mind
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...a story of electronbirdies: no way gettin anywhere 'overvoltage' that is more than battery Voltage... dont drive to such passing bird spots.

Healthy solenoids get 11-14Volts - Nissan FSM.

Is there any other field you think you are an expert at, because this one is definately not your forte.You spew more un researched bullshit than anything Iv'e heard before.We are having a great time following your posts and having a good laugh.We get together and read your posts and split a gut.We compare your mindless ramblings to idiots we have known in the trade over the years."remember the guy that set of airbag modules off while disconnecting the battery for code clearing?"
Get with the new technology or shut-up.

[infinman]

BTW: What does the cartoon of the car supposed to represent?