4T60E in failsafe mode

I've got a 95 Buick Regal 3.8 with the 4T60E transmission. Over the
life of this car, this transmission has given me no problems
whatsoever. Recently, we were visiting some friends in the mountains
that have a very very steep driveway. We were parked on the incline to
wait for them to move a car so we could come up and park on level
ground. When they did, my wife shifted into drive and floored it so
that the tires squealed. Apparently, she was afraid the car would roll
back if she didn't floor it. When we left later that day, the service
engine soon light came on and the transmission went into failsafe mode
(3rd only during drive, can select 2nd and 3rd manually). I took it to
Advance Auto and they pulled up the following codes for me:

Current Codes:
P0640 Quad Driver Module QDM 1 Fault
P0650 Quad Driver Module QDM 2 Fault
P0755 F31 Transmission Solenoid Failure

History Codes:
All of the above codes as well as -
P0705 PRNDL Switch Failure
P0740 Torque Converter Clutch (TCC) Failure

Dealership only told me that the problem is internal and would cost
$1500 to $2500 to fix. I can install a new/rebuilt transmission myself
for much less than that. Based on these symptons, do you think I'd be
better off replacing it, or would a repair from a reputable
transmission shop likely be a better option?

I think a lot depends upon the mileage of this unit.

If you're getting up toward the 100,000 mile level, I would do some soul
searching about
whether to repair it or trade for a newer car.

Depending upon where you live, you can have that tranny overhauled in the
range of $1000-1200,
turnkey, by a reputable shop. (Forget the dealership, unless you can find
where Ian works.)

If a garage starts 'fixing at' the apparent problems, you have to be careful
that the charges don't
mount up to more than an overhaul.

Currently at 155,000 miles. Other than the above problem, it runs great.

"hoyer801" > wrote in message
oups.com...
> Currently at 155,000 miles. Other than the above problem, it runs great.

IMHO, that transmission is long in the tooth. I suspect that an overhaul
will run you in the neighborhood of a grand and change, but a patch job
alone might
approach that and you still wouldn't have a strong platform to work with.

I doubt that the 'goose' your wife gave it would have lamed a strong tranny,
but may have
been the straw that broke this ones back.

Decision time...

Fix the Quad drivers codes first. I had a 95 LeSlober. Codes indicated a
quad driver fault, an EGR fault, and a problem similar to yours {limp
home mode in trans). Dealer said replace the computer($200.00), replace
the EGR valve ($150.00), plus another 150 in labor. I told them
nevermind, and pulled out the schematics, and found that a fuse that fed
one of the quad drivers was EGR, and one fed the trans solenoids. I just
couldn't find the fuse. Finally found it behind the passenger side kick
panel. Replaced the fuse and all worked well. Dealer would have charged
me 500 for this. Quad drivers supply power (or grounds) to systems that
have a medium current requirement . The quad driver fault could cause
the solenoid failure.

KenG
wrote:
> I've got a 95 Buick Regal 3.8 with the 4T60E transmission. Over the
> life of this car, this transmission has given me no problems
> whatsoever. Recently, we were visiting some friends in the mountains
> that have a very very steep driveway. We were parked on the incline to
> wait for them to move a car so we could come up and park on level
> ground. When they did, my wife shifted into drive and floored it so
> that the tires squealed. Apparently, she was afraid the car would roll
> back if she didn't floor it. When we left later that day, the service
> engine soon light came on and the transmission went into failsafe mode
> (3rd only during drive, can select 2nd and 3rd manually). I took it to
> Advance Auto and they pulled up the following codes for me:
>
> Current Codes:
> P0640 Quad Driver Module QDM 1 Fault
> P0650 Quad Driver Module QDM 2 Fault
> P0755 F31 Transmission Solenoid Failure
>
> History Codes:
> All of the above codes as well as -
> P0705 PRNDL Switch Failure
> P0740 Torque Converter Clutch (TCC) Failure
>
> Dealership only told me that the problem is internal and would cost
> $1500 to $2500 to fix. I can install a new/rebuilt transmission myself
> for much less than that. Based on these symptons, do you think I'd be
> better off replacing it, or would a repair from a reputable
> transmission shop likely be a better option?
>

I believe I found the fuses controlling the quad drivers - rather large
60 amp blade fuses, right?. Upon visual inspection, they seem to be
just fine. Checked the electrical connectors as best I could. Again, by
visual inspection only, those look fine. Do I need to get a test light
and check these out for sure (lost my old one somehow)?

I believe I found the fuses controlling the quad drivers - rather large
60 amp blade fuses, right?. Upon visual inspection, they seem to be
just fine. Checked the electrical connectors as best I could. Again, by
visual inspection only, those look fine. Do I need to get a test light
and check these out for sure (lost my old one somehow)?

Get it scanned with a trans capable scanner, this should reveal what is
going on.
> wrote in message
oups.com...
> I've got a 95 Buick Regal 3.8 with the 4T60E transmission. Over the
> life of this car, this transmission has given me no problems
> whatsoever. Recently, we were visiting some friends in the mountains
> that have a very very steep driveway. We were parked on the incline to
> wait for them to move a car so we could come up and park on level
> ground. When they did, my wife shifted into drive and floored it so
> that the tires squealed. Apparently, she was afraid the car would roll
> back if she didn't floor it. When we left later that day, the service
> engine soon light came on and the transmission went into failsafe mode
> (3rd only during drive, can select 2nd and 3rd manually). I took it to
> Advance Auto and they pulled up the following codes for me:
>
> Current Codes:
> P0640 Quad Driver Module QDM 1 Fault
> P0650 Quad Driver Module QDM 2 Fault
> P0755 F31 Transmission Solenoid Failure
>
> History Codes:
> All of the above codes as well as -
> P0705 PRNDL Switch Failure
> P0740 Torque Converter Clutch (TCC) Failure
>
> Dealership only told me that the problem is internal and would cost
> $1500 to $2500 to fix. I can install a new/rebuilt transmission myself
> for much less than that. Based on these symptons, do you think I'd be
> better off replacing it, or would a repair from a reputable
> transmission shop likely be a better option?
>



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Wouldn't the buick dealership have done this?

Maybe they did what I am going to suggest.. I would disconnect the the
electrical connector on the trans, seem if any corrosion, record the codes ,
clear the codes and see what happens. This refers to the shift solenoid in
the trans, that is why it is in " limp mode", doesn't necessarily mean the
entire unit has failed, a bi-directional scanner can command these shifts to
confirm solenoid operation. The solenoid could have caused the quad codes by
overloading the circuit.
"hoyer801" > wrote in message
oups.com...
> Wouldn't the buick dealership have done this?
>
>



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