Transmission issues

[slowshow]

I recently had the AX4N rebuilt. The shop was absolutly aweful. Everything from connecting O2 sensors wrong to vacuum lines unplugged, you name it. Well, it has been a month after the rebuild and I finally got the car running again, and I now notice it shifting funny. It doesn;t shift wrong, or hard, or slip, or anything. It just shifts on its own. Downshifting to be exact. Every 20 seconds or so, it down shifts a gear. I have tested it at 30 mph and 85 mph and most incrememnts in between. It does it with overdrive on and off. It feels as if you have hit the gas to accelerate, so it downshifts a gear, and the 2 seconds later upshifts again, but slowly. Meaning you can actually feel the car downshift, especialy if you are accelearting, but it very lightly shifts back into final gear.

I took it to another local shop to have them check it out. They pulled no codes. Went for a test drive and could not feel anything. I asked them if I could go with them for the test drive, but they said they were too busy to go back out, and that I should drop it off. Basically, they told me nothing was wrong.

I am taking it back to the shop that rebuilt it in the morning, to address this issue, along with a few others. I was just wondering what I can do to fix this on my own, as I did with finding the mixed up 02 sensors.

Much help would be appreciated. I hate the fact that it has been 2 months and $2,400 later, and my car still does not drive as it should.

Thanks in advance!!

 

[slowshow]

Shop says nothing is wrong and that's the way it's supposed to be. He also completly blew me off about the other issues I have. Mark this one down as stupid tax, because I really can't do anything else with the guy. The law says I have to give him a chance to repair his own work, and I already decided that unless the transmission falls out of the car, he will never see me at the shop again. I already have an appointment set for another shop. Apparently this shop is the real deal here in the middle Tennessee area, the shop I should have went to in the first place...

And it's not downshifting. It's the torque converter unlocking. So now, I assume something is telling it to unlock when it should not be. TPS, brakes, bad pressure sensor, faulty converter...?

 

[SHO U UP]

I hope you didn't go to Cottman transmissions. :shakehead

 

[slowshow]

No. Never hear of them . The shop I went to was a repair shop, not transmissions only shop.

 

[slowshow]

So no educated guesses? I have an appointment with one more transmission shop here in town. If they can't fix it, or even acknowledge that it is not functioning correctly, I will just have to fix it myself. Just need to figure out what factors a tc locks and unlocks and trace what's telling it to unlock every 20 seconds...

 

[MichiganSHO96]

Dont these car have kick down cables or tv cables? I would check into that.

 

[slowshow]

Alright. Here's the deal so far. 3 different shops say it's not the transmission, but the car itself. Something is telling the tc to unlock, which is what was said before. They all referred me to a place in Nashville called AES. There they can put a "scope" on it to run live, i guess more in depth than the tranny shop scanner. Looks like a sensor of some sort, but which one?

 

[Daedalus]

The Gen 3 SHO has a well-known "issue" wherein the torque converter unlocks whenever the A/C compressor kicks in, and the climate control system runs the A/C compressor a LOT regardless of whether it's heating or cooling. All of these cars have that programmed in from the factory, and as far as I know the only way to "fix" it is to have your car programmed with a custom tune.

I'd recommend you try driving for a bit with the climate control turned "Off" and see if you still have the locking/unlocking.

 

[slowshow]

Yessir. Does it regardless of HVAC on or off. But if that were the case, wouldn't it have done that before the rebuild? Or just coincidence that after...?

 

[bacernate]

What year is your car? The tcc solenoid has a different ohm readin for 96-97 and 98-99. Many trans shops have inadvertantly put the wrong one in. It is very likely that the is a piece of debris in the valve body somewhere. I had a trans rebuilt in a little chrysler and the tc didn't lock up for like a month and then it started working. A new trans can also feel completely different from the old one if it was really shot.
I just got my grand cherokee running and couldn't believe what it felt like driving something with a normal tc. The tc in the sho is a pos.

 

[slowshow]

The vehicle is a 1997. I am aware of the ohm reading difference in the solenoid. Nevertheless, the shop says that it does not matter. The ECU compensates for that. I read the TSB that explains it.

If anything, the car drives worse now that it has been rebuilt. If it is "fixed" now, I want it broken again...

 

[1995mtxsho]

The ECU wont compensate for an incorrect TCC solenoid. It will, however, be subject to overloading the driver in the ECU.

Did the shop replace the torque converter? If not, they should have. If they did it would also require the SHO specific converter. An ignorant shop may not know there is a difference.

 

[SHOZ123]

You absolutely need the correct TCC solenoid.

 

[slowshow]

Daedalus is correct. Every time the A/C cycles the tc unlocks. HOW TO FIX? Is that correct that the only way is to "tune" it out? And to be a little more accurate, when the heat is on, it only does it when the defrost is on, as I guess that is what keeps moisture out.

And about using the correct parts, it has the correct parts. That's why it took a month to build, because he kept getting wrong parts. TC is also new. The scanner revealed a slightly higher than normal slippage rate. Anything to do with incorrect TCC. As far as driveability goes, as long as the HVAC is OFF, everything on the car is perfect.

Mr. Nimz...?

 

[1995mtxsho]

TCC is in the converter. Hence my comment about them using the correct SHO specific converter. Unless you have an invoice with part numbers (doubtful) I wouldn't assume any story that a shop gives you as accurate, nor would i assume the parts are correct by someones 'word'. Especially in the world of these very uniquely configured transmissions.

It does sound however that what you are experiencing is perhaps a normal thing.

 

[SHOZ123]

Daedalus is correct. Every time the A/C cycles the tc unlocks. HOW TO FIX? Is that correct that the only way is to "tune" it out? And to be a little more accurate, when the heat is on, it only does it when the defrost is on, as I guess that is what keeps moisture out.

And about using the correct parts, it has the correct parts. That's why it took a month to build, because he kept getting wrong parts. TC is also new. The scanner revealed a slightly higher than normal slippage rate. Anything to do with incorrect TCC. As far as driveability goes, as long as the HVAC is OFF, everything on the car is perfect.

Mr. Nimz...?

Most aftermarket rebuilds use the same SHO TC as the Gen 2s. They usually have SHO in the part number. You need the F68, stock is 4 dimples.

From BulkPart.com

F58 series converters have a 23 spline turbine shaft and the F68 series converters have a 25 spline turbine shaft.
You must match metal stamp codes before ordering!

25 spline & 2 dimples on Turbine hub = Check codes for On-Off or Modulating clutch!
25 spline & 3 dimples on Turbine hub = Single plate modulating clutch
25 spline & 4 dimples on Turbine hub = Multiple plate modulating clutch

F68ESHO
11 inch diameter, .825 inch pilot, 25 splint turbine, 18 spline pump drive, no drive on hub with 1.655 inch-1.658 inch bushing, 4 mounting studs, modulating clutch type unit, unit has an inset impeller for HIGH STALL

You could try disconnecting the AC clutch , low and high pressure switches to see if that would stop the cycling but I don't know if that would work. A tune definitely stops it as long as the TC is in good shape.

 

[slowshow]

Mr. Nimz,

Would you suggest I forward this information on to the rebuild shop to see if these parts were used? I'm affraid that if I do, all he has to say is, "Yes, those are the parts I used."

Then I would be at a point of pulling it myself to check, or having another shop pull to check. From what I have gathered so far, the car runs perfect, as long as the A/C is not cycling. Would that be grounds enough to say that everything else is correct, or would they cyclking issue be a result of bad/incorrect parts?

I guess what I'm trying to say is, instead of pulling it again (myself or another shop), would it be safe to assume (and I really hate to use that word) that all is coorect mechanically (meaning correct parts), and that this is just simpy an electrical issue?

And is Daedalus correct, in that this is a know issue? From what I gathered on v8sho.com and a couple other sites, I don't remember coming across anything like this, not saying that it was not there, just saying it does not ring a bell.

I have been considering a tune, as this car is only getting the following performance mods...

- Lowering
- CAI
- delete of flex, 3rd cat, and res
- aftermarket muffler of some kind
- and wrap it all up with a tune (firm believer in tuning!!!)

And what did you mean by disconnecting the A/C switches? Did you mean disconnect them and still tuen the unit on inside the car and see if it still does it? I guess that would make sense to see if it was still getting an electrical signal to the ECM, vs a mechanical pressure change to the TC.

Thanks a bunch for all the input guys... Great stuff...

KEEP IT COMING!!!

 

[SHOZ123]

If the converter is locking but cycling on and off while at cruising speeds and the AC on then that is normal Ford programming.

 

[slowshow]

Then riddle me this.... If that is the case, why did it not do it before the rebuild?

 

[SHOZ123]

It did and you didn't notice it. I don't know of any Gen 3 SHO with stock programming that does not do this.