the Famous transmission hunting has returned

[yodawill2000]

For the last few days I have noticed my transmission going in and out of lockup.
Ive also noticed when I first pull out of the driveway and start up the street ,
with even pedal pressure the rpm's go up and down a tad.
The speed also changes so she's not slipping.
I'm thinking the two have to be related.
transmission Diags pass fine and the consult shows the TPS dead on.

Anybody have any idea what might cause these two symptoms ??

I need to dig into the FSM and see what all parameters must be met to achieve lockup.
All I know of for sure is the transmission temp.
It doesn't even try to go into lockup till the temp gauge is almost at operational level. (Just shy of halfway up)

[Cool_J30]

This probably won't be of much help since it's not on a J, but the last time I had this happen to me was on a Chevy Lumina years ago and it 1st started doing similar to what you describe, then within a week or so it would die when ever you came to a stop (like a manual trans that you hadn't pushed the clutch in). Yup the torque converter lock-up... However the good news is it wasn't the TC itself, it was just the solonoid that operated the TC lock-up. It was a pain to change it, but it was a cheap part...

I hope your fix is even easier. The varying engine speed has me wondering if it is even the trans at all...

[yodawill2000]

Seems the varying rpm hop is when its still warming up.
Hmmm...

[driverdriver]

Yoda,

Similiar thing happened to me many years ago. The J30 transmission is one of he first adaptive transmissions on the market(meaning it learns how you drive and stores the information) and sometimes it forgets. When it happened, my car was still under warranty and the dealer "reflashed" the unit, which solved the problem. I have gone through the FSM and still don't know what they did( I don't see a reflash procedure), but whatever it was, it worked and still is working.

[Cool_J30]

Once again, from ignorance on the actual J, but from what driverdriver is saying, I'm going to extrapolate that most of the other "learning" transmissions didn't store their "thoughts" anymore if they had a total power discharge (not just a battery swap out).

This came up on another thread, but if you're game, try disconnecting the batter + lead and turn on the lights or anything else that will drain the capacitors still trying to hold those "thoughts"...

I'm old enough to call this a cold boot...

[yodawill2000]

I tweaked the TPS this morning (Slowed down the idle)
Pulled the connector to register the change and it seemed a little better on the way in.
I'll hook the consult up tonight to see what the voltage is.
Still have the rpm change issue when warming up.
Might be a totally separate issue.

[GerryO]

Still have the rpm change issue when warming up.
Might be a totally separate issue.

Sounds too coincidental to me, as along with MAF, vehicle speed, engine temperature, KS, TPS, air regulator/AAC/IAC valve positions, CPS and who knows what other ECM input information, engine rpm is probably a significant factor in the equation that determines transmission shift points. Hope you are successful in tracking down a definitive answer to the problem.

[yodawill2000]

I planned on checking the AAC/IAC valve this weekend.
As well as installing the rear struts and both front outer Tie rods.

Gonna be a sweaty weekend in the ole' driveway !!

[GerryO]

I'd use the CPS output signal routed through the ECM to the tachometer to physically count and display engine rpms. Possibly a poor connection between the CPS, ECM and the tach, or a bad ground? Time to check the wiring diagram. Best of luck.

[driverdriver]

Once again, from ignorance on the actual J, but from what driverdriver is saying, I'm going to extrapolate that most of the other "learning" transmissions didn't store their "thoughts" anymore if they had a total power discharge (not just a battery swap out).

This came up on another thread, but if you're game, try disconnecting the batter + lead and turn on the lights or anything else that will drain the capacitors still trying to hold those "thoughts"...

I'm old enough to call this a cold boot...

Cool_J30,

Your thought process here makes sense. I would try it.

[yodawill2000]

I will try that, as well as clean\tighten all sensor connectors and Maf connector and apply dielectric grease this weekend.
Ive been meaning to do that for awhile.
I also will be cleaning the MAF sensor and throttle plates.

I informed the wife there will be no Hunnydo's this weekend as I will be spending the weekend with my "Other" Wife.

[GerryO]

Seems the varying rpm hop is when its still warming up.
Hmmm...

Reading about tach signal sources; they are often taken from ignition coils and voltage regulators. Noted some references to bad ground connections, electrical interference/cable shielding, dirty calibration pots and failing ignition coils.

Don't know how the J30 tach might source its' signal from the VG30DE engine with its' six separate coil packs, but suppose a signal/spark at any one of the cylinders would indicate that another engine revolution has been turned, and then there's the CPS with its' internal optical sensor and laser cut wheel that's turned directly by one of the camshafts.

[yodawill2000]

Its not just the tach thats surging up and down slightly.
the engine is, with the new exhaust setup I can hear it going up and down about 100/150 rpms.

[GerryO]

Air regulator/AAC/IAC valve clean-ups make complete sense then. When's the plenum pull?

[yodawill2000]

AS soon as it's not 100 degree's outside

[GerryO]

AS soon as it's not 100 degree's outside

It's the humidity that gets me, along with them 'gators at Brazos Bend. Is running over an armadillo better than hitting a skunk (by far the most common form of roadkill in Sonoma county)?

[Cool_J30]

AS soon as it's not 100 degree's outside

It's the humidity that gets me, along with them 'gators at Brazos Bend. Is running over an armadillo better than hitting a skunk (by far the most common form of roadkill in Sonoma county)?

Totally off topic (but fun)...
From living in Houston: Humidity sux, even if you try to think of it being tropical. Skunks squish easier but also you better park your car outside for awhile. Deer are the roadkill (of their choice) up here. At least the wife was in the Expedition last she hit one (survival rate deer = zero. Damage to Expy = zero). Streetbikes in late afternoon/early evening or early morning and you better have Air Ambulance coverage...

[yodawill2000]

We have Dillo's, Skunks ,Coon and coyote to dodge here.
And a Bobcat here and there but they are pretty good at getting out of the way.
I wont even mention squirrels because they almost ask for it !!

[Cool_J30]

yodawill2000:
With that other thread on trans fluid fills, it reminded me of this one -- what did you ever find out, or did you solve it?

[yodawill2000]

Still tweaking.
I have lockup at 60 but it still hunts around in the 40 mph range.
I have the TPS at 4.8 right now.
I'm using the emanz consult so I might try getting a reading with a meter at the TPS.
Although the consult does show a change if i change the tps ever so slightly.

[yodawill2000]

Anybody have a working inhibitor switch laying around ??
I'm running out of things to try.
If its the lockup Solenoid I'm hosed.

[GerryO]

Cleaned/checked the MAF lately? Once had issues with my '97 F150 that I swore were engine and transmission related, that turned out to be simply caused by a dirty MAF.

Am curious to know how you have compensated for the increased idle speed caused by the increased TPS output voltage and how it may have also affected shifting and crusing rpms? Have thought about buying and installing a new TPS for my J30 just for drill, as they seem like they should get a lot of wear, especially in a couple of specific locations. Is the output voltage fairly steady at constant speed?

We have three Pick 'n' Pulls in the area that currently have a combined total of eight J30s, but have never knowingly gone near the inhibitor switch. Is it accessible from up top?

http://www.picknpull.com/check_inventor ... istance=20

[yodawill2000]

No matter where I have the TPS set , It still hunts, just in different speed ranges.
After warm up it will lock up for about 15/20 seconds then unlock.
Over and Over !!!
Driving me nuts.
I'm afraid to think of what damage I'm doing to her !!

After changing the tps setting ,I disconnect it for about 20 seconds then plug it back in.
Doesn't seem to change the idle speed at all.

And I cleaned the Maf over the weekend.
Haven't cleaned/tightened the MAF connector though. Hmmm.

[GerryO]

http://www.auto-facts.org/throttle-position-sensor.html

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

[yodawill2000]

Looks like I should try a new TPS then !!

[GerryO]

Sorry to read that a new TPS didn't help. What are the current symptoms and are you still running the additional cooler?

[yodawill2000]

Although the TPS made a difference in shift points, it still goes in and out of lockup at 60 MPH.
It will lockup for say 15 seconds then unlock , then lockup ect.
Yes the cooler is still installed.
I might add I bypassed the in rad cooler.
I planned on putting it back in the loop when it gets cooler.
Been over 100 here everyday for weeks !


And the transmission Diags have no errors.

[yodawill2000]

Does anybody know where the transmission fluid temp sensor is ??
I have noticed its acts different on the way too work (85 Ambient) than it does on the way home (100/105 Ambient).

[jdurrty]

You have to hit the zoom button two or three time to see the full sized picture

[GerryO]

Yes the cooler is still installed.
I might add I bypassed the in rad cooler.
I planned on putting it back in the loop when it gets cooler.
Been over 100 here everyday for weeks !
And the transmission Diags have no errors.

Always considered the in rad cooler to be a heater too and part of an effort to maintain a more constant transmission fluid temperature, as the engine temperature is normally so stable.

Is there enough free-play in the kick-down switch adjustment?

Would you otherwise recommend installing a new TPS and where did you pick up your new one?