Mohammed_z

A friend owns a C5.

Changed the trans fluid. And the day after the transmission acts crazy.

it acts like slipping clutch in manual transmission and then it wont shift to 4th. and sometimes to 3rd. Then tranmission high temp message appeared.


Some say , changing the fluid will cause this. But I don't agree since changing fluids is a routine maintenance in the owners manual.


The main question is , what cause transmission failure after fluid change ?

choosing the wrong oil ?
using the old fluid ?
using the same filter ?

other than that ?

ZeeOSix

Did he use the correct auto transmission fluid? If so, I can't imaging changing the fluid would hurt the transmission unless he under filled it and it burned up the clutches.

Mohammed_z

Thats what I was telling him, either under filled or wrong fluid !

Dcollins3208

I'd assume under fill. After an initial fill, he should have turned on the engine, let trans temp reach somewhere within the 80-120 ball park, shift through all gears, shift back to park and top off. Just did it recently while installing trans cooler.

Clyde2

It's been my experience that most times people don't change the fluid and filter in the transmission as a maintenance thing... Usually they were having a problem before the service, always test drive to verify a problem or just maintenance .

Mohammed_z

Good point !!

C5Natie

You'd be surprised how interchangeable these atf fluids are so I would say he underfilled it or maybe theres an obstruction somewhere. Also I always change the filter when I service the trans. The corvette filter has a long tube under it to suck up fluid. The regular filter for a 4L60E does not. This can also cause the trans to starve for fluid.

TEXHAWK0

How many miles since the fluid had been changed, if ever?
Sometimes if you wait too long, then fresh fluid can free up deposits and cause an obstruction in a passage.

dankhts

big time! if the fluid is dark, burnt, thick, has a lot of clutch material floating around in it, never been changed etc, best to leave it alone or it'll likely cause a failure quicker by changing it! Hopefully though it's just down a bit....

Bluefire

Re-check the fluid level. The service manual strictly states that the fluid temp MUST be between 86F - 122F when doing a level check.

I checked mine when it was hot and it was "full". I then waited until it cooled to the proper temp and I found I was 22 oz. low.

HTH

jim993

There have also been reports of new filters that are not vacuum tight. A vacuum leak in the filter will starve the transmission of fluid.

A new filter should be vacuum checked before installation by sucking on the round tube that goes into the transmission while at the same time sealing the oval filter inlet with the palm of your hand. A good filter will hold this vacuum.

OneFast1

Could it be an improper filter install? It reads as though the transmission is starving for fluid. Assuming that fluid level is correct, I would pull the pan to be sure the filter is tight and not pulling air. If the filter was not changed, could it have been hit or jarred?

jim993

The fluid level must be checked with the engine RUNNING. Transmission in park.

bracketshark

I'd bet the wrong filter is installed.

reactor2

My uncle owned a small local courier company that owned several Chevrolet vans, equipped with TH350s. They found that if they did not change the transmission fluid ever, the transmissions would last the entire service life of the vehicle. However, if they changed the fluid (I think it was around 100k miles) the transmissions would fail within 5k miles. It happened frequently enough to make them change their policy.

Mohammed_z

I think putting new oil and let it drain again will take away those deposits !?


This is weird !
Then why there is a fluid change service !!

Evil-Twin

something was wrong before the fluid change that prompted the owner to change the fluid, or the wrong fluid was used. or it was an error in the correct fill capacity.

cv67

most change due to a problem and of course blame fresh fluid for the problem.

Keep the trans fluid serviced dont buyi into that 'good for 100k' bs like I did. It costs

Dave02C5

in autos i'd drop the pan every 30-40k. never a problem here. either the trans is roached or the fluid is low and by having low fluid and having intermittent pressure on the bands, probably roached it as well.