PLEASE Help Its the Transmission Again

[daluvabull]

Just replaced my 3rd transmission in 5 yrs- ugh
1st Cottman rebuild
2nd Local shop reuild
3rd used 4.44 with rear diff and shift mod

Currently shifts are irratic. Does not seem that it shifts down to lower gears until it warms up- resulting in a blinking power light. At times it shifts good. Other times it seems to stay in 3rd. If manual is selected, it most usually shifts ok. The power light does not luminate at start up or when the ignition is on. Consequently, an error code cannot be identified. The mileage is 182.5K. It has an externl cooler and filter. All warning lights illuminate under hard acceleration while attempting to shift down from 3rd to force a shift to 4th on the freeway. Additionally, all warning lights fade on and off occassionally. The car will roll while in drive with the engine off.

Bad install, connection or TCU? If TCU, any ideas on availability and cost of a used one? Where is the TCU located. A search of the How-To documents was not fruitful.

Of course any insight or suggestions that can be offered are greatly appreciated.

Peace,

Jeff

[Trevor]

Greetings Jeff,

"All warning lights illuminate under hard acceleration while attempting to shift down from 3rd to force a shift to 4th on the freeway. Additionally, all warning lights fade on and off occasionally."

This could indicate an alternator rectifier problem with A.C. being imposed on line. However it is difficult to tie this in with Hard acceleration. Alternating current could possibly be playing havoc with the TCU, but this has not been previously reported as a problem.

Exactly which warning lights illuminate? Could any wiring have been upset during the transmission installation? Is the filter a common denominator, in respect of your several transmission failures?

Cheers, you need them. Trevor.

[daluvabull]

Thanks for the reply. I believe only the red lights illuminate. I think I have chosen shops that could not work on the SVX properly. Wiring errors are quite possible after the last install. Again, in hindsight, I am not confident of the previous shops work. It has been difficult, and expensive, trying to correct the transmission problems. If I could be directed to where literature is to illustrate the wiring paths and units that could be influencing the operation of the transmission, it wold be most appreciative.

Again, thanks

Jeff

[huck369]

We had a member at the last Dragon Meet experience similar issues, and it turned out that his crank pulley was separating....not enough voltage getting to the TCU to control shifts.

I am assuming you have a set of matching tires on it, and keep them rotated....as unmatched tires will eat the 4EAT, and an external tranny cooler........and if you're on your third tranny, either you have another issue, or you just abuse them, if it's the latter, then the old saying " You gotta pay, to play" comes into mind.

[daluvabull]

The crank pulley was replaced in 2004. I drive conservatively-really. It seems difficult finding a dependable shop around Houston, other than the dealer, that can work on the SVX. Could a faulty alternator cause an electric drain that would result in errorneous TCU signals. The alternator has not been replaced- that I know of. What puzzles me is why I do not get a power light on start up. I am not able to extract codes from the TCU.

Thanks for the information. PLEASE keep it coming.

Jeff

[huck369]

Most places will check you alternator for free, definitely worth checking out..

You still didn't say if you have matching tires on your car, you sound like someone who would, but it is important information when talking about bad trannys...

[Trevor]

Originally Posted by daluvabull

The crank pulley was replaced in 2004. I drive conservatively-really. It seems difficult finding a dependable shop around Houston, other than the dealer, that can work on the SVX. Could a faulty alternator cause an electric drain that would result in errorneous TCU signals. The alternator has not been replaced- that I know of. What puzzles me is why I do not get a power light on start up. I am not able to extract codes from the TCU.

Thanks for the information. PLEASE keep it coming.

Jeff

It is not a matter of "an electric drain," or low voltage. A faulty rectifier within the alternator will result in alternating current being imposed on the normally 12/13 volt, Direct Current system. Often this fault is not picked up by auto electricians doing a test. Make sure anyone testing knows their job and explain that you suspect a rectifier fault.

It is not possible to make certain diagnosis from afar, but the alternator is a likely cause. The previous post mentioning a failing pulley could also have resulted in a "dirty" output from the alternator. Two of us pointing to the alternator is not by accident.

[daluvabull]

Yes, same size, brand, model...

Again, thanks.

Jeff

[daluvabull]

The search continues...

Removed the alternator and has it tested at NAPA. Specificly requested to check the rectifier. They said it all check good. Replaced the alternator.

Seems to shift once the transmission fluid temp gets hot.

Should the Mobil-1 M1-301 external transmission filter be removed and replaced with a new line? Could it be restricting proper flow and pressure?

Still puzzled...why does the power light not illimuniate at start up. It does blink the first time the transmission downshifts from 3rd after warm-up. However, the error codes cannot be extracted. Do TCUs go bad? The SVX does have 182.5K miles.

Suggestions are greatly encouraged and appreciated...

THANKS,

Jeff

[Trevor]

Originally Posted by daluvabull

The search continues...

Removed the alternator and has it tested at NAPA. Specificly requested to check the rectifier. They said it all check good. Replaced the alternator.

Seems to shift once the transmission fluid temp gets hot.

Should the Mobil-1 M1-301 external transmission filter be removed and replaced with a new line? Could it be restricting proper flow and pressure?

Still puzzled...why does the power light not illimuniate at start up. It does blink the first time the transmission downshifts from 3rd after warm-up. However, the error codes cannot be extracted. Do TCUs go bad? The SVX does have 182.5K miles.

Suggestions are greatly encouraged and appreciated...

THANKS,

Jeff

Jeff, the only option is to follow your nose, and you are tracking well so far.

Good option to rule out the filter. Can you bypass it, using a short length of metal tubing by way of a test? Otherwise a change of filter and a careful check, would probably be money well spent in any event.

Low or intermittent pressure, is certainly a possibility. It is strange that the a fault code is not being locked in memory.

Did you specifically mention a possible AC output when the alternator was checked? Do you posses or can you borrow a cheap basic multi meter? If so, set it to a low AC voltage range and measure for any small level of alternating voltage/current across the battery at say 2,500 RPM. This has proven to be a successful test.

We are all with you on this, Trevor.

[daluvabull]

Thanks Trevor. I hope to find to to give it another try this weekend.

Have a great week!

Jeff

[daluvabull]

UPDATE
Removed extra fuse linked wire from top of alternator to battery positive terminal. The previous owner must have done the alternator mod.

Was able to get power light. Ran a diagnostic and recieved:
12 Duty solenid-B
24 Duty solenoid-C

Is it most likely my 3rd installed transmission is toast?
If so, I really cannot justify expending in excess of $2750 for the fourth time in 5 years.

Most likely I will post the SVX for sale. It just had a repaint in June-09, and the interior redone in gray pleather with red stitching, new headliner, a Pioneer CD player with USB/aux input, and Infiniti speakers in Apr-2008.
I will post an ad in the for sale section as soon as current pics are taken.

THANK YOU for your assistance. This is truly an excellent community for the SVX enthusiast!

Peace 8-|

Jeff

[sowise]

I definitely wouldn't sell the car if I was you. Check out ECU tune they can give you an upgraded performance valve body with all new solenoids for $600 if you don't want to replace the solenoid yourself. As for the C solenoid there are plenty of how to's and boards posted on this and none of this will cost $2750. Even a ECU tune rebuilt trans is $999.
I understand your frustration for having had to replace your transmission so many times but I am not sure it needed to be replaced that much. Up to you though really but I would hope you would keep your car.

[Trevor]

Originally Posted by daluvabull

UPDATE
Removed extra fuse linked wire from top of alternator to battery positive terminal. The previous owner must have done the alternator mod.

Was able to get power light. Ran a diagnostic and recieved:
12 Duty solenid-B
24 Duty solenoid-C

Is it most likely my 3rd installed transmission is toast?
If so, I really cannot justify expending in excess of $2750 for the fourth time in 5 years.

Most likely I will post the SVX for sale. It just had a repaint in June-09, and the interior redone in gray pleather with red stitching, new headliner, a Pioneer CD player with USB/aux input, and Infiniti speakers in Apr-2008.
I will post an ad in the for sale section as soon as current pics are taken.

THANK YOU for your assistance. This is truly an excellent community for the SVX enthusiast!

Peace 8-|

Jeff

You have rather a desperate situation and therefore I am willing to stick my neck out in an effort to assist. Your exact problem has to my knowledge, not been previously reported here, but there is always a first time with everything.

I very much doubt that you have a fault within your transmission. Both B & C solenoids playing up at once would indicate a possible faulty pulse width modulation signal from the TCU.

Something is haywire within the charging system as there has been a change after you removed the alternator direct connection. Importantly you also have advised fault indication lights being abnormal. These two symptoms indicate probable AC on line, caused by a faulty diode in the alternator and this regardless of the test carried out.

The change after removing the "alternator mod." indicates a possible wiring fault. This mod. bypasses the fusible link and existing wiring to the alternator.

Everything indicates further careful investigation. Do not put complete trust in others who do not have exact experience, in this regard.

I say again ----Do you posses or can you borrow a cheap basic multi meter? If so, set it to a low AC voltage range and measure for any small level of alternating voltage/current across the battery at say 2,500 RPM. This has proven to be a successful test.

Please test everything again, with the mod. removed, and exactly advise on every item which is abnormal, including details on which lights are playing up. Your frustration is understandable but you have a lot at stake.

[svxfiles]

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