1st to 2nd gear shifting varying

[Pat]

As of late I've noticed my WOT shifting point from 1st to 2nd varies. It's set to 6200 RPM by my Xcal-1 flash tuner, but the car may shift from 6200 to 6600+(I get off the pedal, quick). this condition is intermittent. The shifting from 2nd to 3rd at WOT seems OK but I rarely get that high in speed since this problem manifested itself so I can't say if 2nd to 3rd is intermittent or not.

At part throttle the car is normal. The car is not throwing any fault codes.

The actual shifting operation (firmness, response) seems correct.

Could the pcm data in the WOT sector have become corrupted?

I reloaded the PCM but haven't attempted any WOT operations until I know more about this problem. Don't want to scatter the motor over the highway.

After reading about TPS (throttle positioning sensor) I don't think that's the problem, but I'm not 100% sure.

Thanks,

Pat:dunno:

[Vortech347]

My old 96 SHO would do that. It would sometimes hit the limiter before it shifted with the superchip program that was on it.

[MENINBLK]

When was the last time you changed the tranny oil ?

[HwyCruiser]

With the mods you list and the cooler weather you may be breaking traction into first gear causing the engine to head towards the rev limiter rapidly.

[MENINBLK]

With the mods you list and the cooler weather you may be breaking traction into first gear causing the engine to head towards the rev limiter rapidly.

In LOUISIANA ???

[HwyCruiser]

In LOUISIANA ???

What, the don't have Januaries in Louisiana? A peak at weather.com shows it's in the 40's-50's there. I could light 'em up pretty easy when it was that cool out with stock tires and n/a bolt-ons.

[LVMarauder]

Not claiming any knowledge of the 4r70w I offer this. Can it be that you are lifting off of the throttle right before the computer tells the tranny to shift, or that you are lifting AS the tranny shifts there by momentarily not being in any gear allowing the momentum of the spool up to carry it to higher RPM's? I sometime get that weird shift if i lift on the throttle at a bad time.

[hal510]

Off topic, but whats the highest rpm we can rev to? Safely?

[Pat]

Answers to questions raised in the thread -

Tranny fluid changed twice 15 & 30K mile.

No traction issue, T/C on, speed at time of anamoly more than 30MPH.

operator technique - Foot steady pressing go pedal to the floor, no let up.

Highest safe RPM - reviewing members dyno charts shows power drop off in low to mid 6K range. I read somewhere that the 4.6 DOHC engine can operate up to 7K, but prolly with different cams than ours.

Pat

[Meteorite]

What it could be (but I hope it isn't!) is your Intermediate Clutch going away.

Burnt or "glazed" Intermediate Clutch friction plates could produce this sort of engine flare as your 4R70W is trying to grab 2nd gear. That is, the calibration may be commanding the shift at the identical (correct) RPM, but sometimes the Intermediate Clutch grabs properly, sometimes it doesn't.

[BigCars4Ever]

Chime in if you know for sure but doesn't the PCM use MPH for shift points? Extreme tune sets the shift points in MPH. The XCAL software may be taking the RPM # you enter and calculating the shift point MPH and inserting that into the PCM table. That would explain the differences cause depending on conditions and the lock up schedule the engine RPM can vary for the MPH. My car will somtimes hit the rev limiter before it gets out 1st cause my shift schedule sets the MPH shift point close to the rev limit. I keep meaning to get around to reducing it by 2MPH to keep that from happening.

[Zack]

The trans will shift at a different rpm from a stop vs. a downshift, if that helps.
Also, if you downshift into 1st at say 15 mph, the shift rpm will be lower than if you downshifted from 30mph.

[Pat]

Thanks for the input guys, of course the post that causes me the most concern is #10 by metorite that alerts me about a possible burned or worn intermediate clutch.

I'll have that analyzed be my local tranny shop.

Looking at the documentation that comes with my new data logging tool, there are 115 different measured or monitored signals that report to the PCM and thus used in determining tranny operation.

Wow, I've got to get a manual that tells me what all these acronyms mean.

As they say in France, "back to the drawing board".

[Marauderjack]

pat....

I have the same problem and JD probably nailed your answer.....poor traction and wheel spin at the 1-2 will cause a "Flare" towards the rev limiter and it is very inconsistant because your traction is inconsistant!!:eek: If your car has Traction Control it will also kick in!!:cool:

I lowered my 1-2 shifts to 5800 RPM's to correct it as the rev limiter will scare the Hell out of ya.....First time it happened I thought I BROKE my motor!!!:mad:

Try lowering your 1-2 shift point and see what happens!!:beer:

Good Luck!!

Marauderjack:burnout:

[Pat]

Well, I visited my performance tranny shop this AM and described my problem to the man with the dirty T-shirt and feet propped up on a desk littered with used, oily parts.

He didn't hesitate with the prognosis, "you have a 4R70W or 4R75W transmission don't ya". "yyyeeesss sir, I studderd.

"Well, mister", he said, "sounds like you have a bad roller clutch or the c-clip has back off the mechanical diode".

"We here at Bubba's Transmission and Donut Shop can fix that, $600.00". "Pay Edna there and she'll schedule you in".

"Honey, will that be cash, check or charge", Edna toned. I fainted. There goes my bling for this year.

[ckadiddle]

Well, I visited my performance tranny shop this AM and described my problem to the man with the dirty T-shirt and feet propped up on a desk littered with used, oily parts.He didn't hesitate with the prognosis, "you have a 4R70W or 4R75W transmission don't ya"."yyyeeesss sir:, I studderd. "Well, my boy", he said, "sounds like you have a bad roller clutch or the c-clip has back off the mechanical diode"."We here at Bubba's Transmission and Donut Shop can fix that, $600.00". "Pay Edna there and she'll schedule you in". "Honey, will that be cash, check or charge" Edna toned. I fainted. There goes my bling for this year.
I am going to go home tonight and kiss my extended warranty. Then tomorrow I will go and kiss my old grade school friend that owns a local transmission shop. Then, I am gonna kiss the heck outta his wife!! :D She's cute!

[rumble]

or the c-clip has back off the mechanical diode".

".


The infamous "C" clip. We have all been warned many times before.
I would imagine the 6 Ben Franklins are mostly for labor. If so that sounds
reasonable.

I would think that having this done as a preventive measure might be
wise.

[Stranger in the Black Sedan]

Rumble, can you elaborate on the C clip? I have rebuilt a bunch of older RWD automatic transmissions but nothing specifically electronic Ford stuff. Is this clip replaceable with the trans still in the car, through the pan?

[Pat]

VEB;

The tranny man said the unit had to come out of the car and be opened up, I asked.

The C-clip under discussion has plagued our trannys since the beginning.

I think DR has a lot of info in his forum about this problem.

It seems the cars with "firmed" up shift pressures are the one's most affected to the clip breaking or being forced out of it's groove.

The fix is minor, assuming no damage to other parts and consists of replacing the OEM part with a "Circlip" (sp) which I think is a locking design.

Maybe someone has a picture or more/better info.

The tranny man at my local shop was very familiar with this problem and the fix. They do a lot of HP Mustang work.

Pat

[Stranger in the Black Sedan]

Thanks pat. Sounds like I'll be alright with stock stuff. Hopefully! I would certainly tackle it as preventative maintenance if it could be done in the car, but not if it has to be yanked to do.