Transmission Question

I have a 1995 Saturn SL-2 with 115k Miles on it. I love the car and
the great gas mileage (30-35 mpg). Like all Saturns of that time it
has had the reverse slam disease since around 60k miles. I baby it
when I put it in reverse to keep from tearing the transmission up
because of this.

I now have a new problem. About 2 months ago, the transmission began
slamming into all gears sometimes. The slamming seems to be worse in
the evening and is either all or none. It either slams or does not.
When it is slamming, the hits are hard enough to bark the tires or
make you think someone has hit the car. Babying the accelerator by
backing off or releasing the pedal to force the shift will prevent the
tire barking, but cannot prevent the slams.

Now for the weird part occasionally the service engine light will come
on and when it does the transmission suddenly shifts smooth as glass
and continues until the car is turned off.

Here are my thoughts, the service engine light is probably activating
a fail safe program in the computer that ignores most of the sensor
inputs and just uses preprogrammed values. The fact that the
transmission runs fine during that time would indicate that there is
likely not a transmission problem causing this but rather the computer
is getting faulty data and giving out bad commands to the
transmission.

I have not pulled the computer code yet. I guess that is the next
step.

The transmission shop wants to rebuild the transmission for upwards of
$1000. I do not think that will correct the problem with the car.

Anybody got another thought about where to start looking?

 

Check out all of the solenoids to make sure they are good. You can do this
fairly easily using an ohm meter. The connector is easy to get at and only
has one small bolt holding it in place on the Top of the TAAT access plate.
The solenoids (there are 5 if I remember correctly) should all measure
nearly identical resistance an that was about 5-8 ohms again IIRC.

Good luck. Solenoids are not too difficult to replace if you are handy.
Read the Saturn Fans forum ... I posted a procedure a couple years back for
doing this...

Good luck!

Bob

 

Thanks for responding.

The saturn users forum has some great info, including how to get to
the valve body and replace it. I looked throught the how to archive
and I'm sorry, but I did not find the proceedure you referenced. Is
there any chance you could post a link for me.

Again, Thanks

 

Here is a post I made back in 3/2005. I know I made another with more
detail, but cannot find it any more. Basically you just need to measure the
resistance on the adjacent contacts on the connector. They should measure
4-6 ohms if the solenoid is good. In my case, the one that modulated the
shift pressure was open circuit so no longer working. There were no codes
set and all gears worked fine, but it "slammed" exactly as you described.

To measure the resistance you need not open the cover ... just remove the
connector which is held in place by one small bolt. Good luck.

Bob

HERE IS THE POST I MADE 3/2005:

MJO,

I wanted to respond to confirm your diagnosis. I took the upper transmission
cover off and then removed the solenoid cover. There appear to be 5
identical solenoids in there and one of the five measured 0.6 ohms compared
to the other 4 which were all 4.4 or 4.5 ohms. I am guessing that this
indicates a complete short in the coil windings, so the solenoid was no
longer operating at all.

From what I have learned, this solenoid modulates the trans fluid pressure
during shifting so if it was not doing its job the trans was seeing full
pressure and this was causing the extremely harsh shifting. I plan to pick
up a replacement solenoid ($56) and cover gasket ($21) from the dealer later
today.
Given that the trans was shifting at the correct speeds and all the gears
were working, I am very optimistic that this will fix the vehicle's shift
problem.

Thank you all for your replies. This is an excellent forum and from my first
posting experience, it appears there are some very knowledgeable as well as
very helpful people here.

Bob

Thanks for responding.

The saturn users forum has some great info, including how to get to
the valve body and replace it. I looked throught the how to archive
and I'm sorry, but I did not find the proceedure you referenced. Is
there any chance you could post a link for me.

Again, Thanks

 

My 1st question would be how often have you changed the fluid and filter
on this transaxle?
Also did you ever try the reverse slam fix?
(the one that doesnt involve removing the valve body)
My next question is what are the codes?

Right now my guess is the valve body is gumming up and as it got worse
the valves started to stick which can cause the ecm to ramp up the
pressure. The transaxle temp gage can give issues also...

I'm not sure what the Ohm values were for a 95 saturn but IIRC in 96 or
so Saturn changed the solenoid resistance values which may not be the
values Bob's giving. Either way they should all be very close to the
same resistance.

 

Take it to satun and have it checked. You can no longer just replace
the valve body because they only sell the whole assembly around $550.
I took mine to saturn and it turned out to be a locking ut o a output
shaft that cost a big $75 to fix. I was told this is a very common
problem on saturns and gives the slamming problem. Shotgun fxing a
tranny is never a good idea, and taking it to a tranny shop before you
really know what is wrong with it is even worse.. there business is
rebuild!