To Change Tranny Fluid or Not To Change Tranny Fluid?? HELP!!
 

Hello all. I have been having an issue with my '03 Impala LS 3.8L Transmission. It started in December and some shuttering pulling out from a stop. Also, it was shifting quick up through the gears. I put an OBD II Scanner on it and it gave me a PO742 Code "Torque Converter Clutch Solenoid Circuit Stuck On". Well, I parked the car for the winter and just got it into the Chevy dealer near me. They ran a diagnostic on it and took it for a couple long test drives and could not get it to throw a code and could not seem to find anything wrong with it. They said that if it was the Clutch Solenoid, that it might have been stuck from the cold and it worked itself free. They set me up with a Vehicle Data Recorder (VDR) for me to use for a week and if it started acting up, to hit the button and it would take a snap shot and hopefully catch a code and what is wrong with it. They said the tranny fluid is very dark to an almost black but does not smell burnt. I don't know what burnt tranny fluid smells like myself but I can vouch that it does look almost black. Now I did tow about 3,000lbs about 2,800 miles back in May of 2009. I have also been involved in an accident on the front passenger side between front quarter panel and passenger door back on July 21st 2009 and had that repaired. The Chevy dealer said it may have to have that Solenoid replaced or could even be a torque converter that needs replacing, but they don't want to be guessing and do unneeded work, hence the VDR. They said the tranny really needs to be serviced as in fluid and filter change and that maybe they would help the issue. My question is, if push comes to shove and my car still doesn't show a code and they are still baffled... should I have the tranny service done? I have just heard stories about how messing with the tranny as in doing a tranny service can make things worse. It is about $150 for the service. I told them I am worried about back flushing or having particles getting up into the tranny from doing the fluid change or even film that is built up over time getting cleaned off from doing this and they said that they do not back flush it and the particles will not get back up into the tranny. Now, given all this info, should I get the tranny service done?? I know you guys know your stuff. Please help me on this decision. Thanks!

my 92 astro awd was giveing me problems with shifting awhile back so i went and had a tranny flush done and it solved the problem for awhile but now its even worse granted i have put alot of miles on it since and has 233,000 miles but to answer your question from what i have read in the past yes it is possible by doing a tranny flush you could make it worse but at the same time it could be that you fluid is just so broken down that its usless and changeing it could maybe solve your problem i mean it might be worth a shot if its still acting up and not throwing codes i know if my tranny fluid was almost black i sure would..

Changing the transmission oil will not stop your problem that thousand of impala owners went throught with the T65 hydramatic. I have been changing my oil every 50,000 miles including the filter and I was going throught the same problrms with delays at start up and sometimes the transmission was going in high pressure mode after the hick up. It is a lost case. They need to be opened and probably the solenoids replaced following with others items as well. Count 3000$ for this job and this is not a D>I>Y> sunday job either. Good luck. Note. This problem usually occurs on high millages cars ( 80,000miles and up)

If trans fluid smells burnt or the trans is having a problem it should not be flushed unless you are prepared to buy a new trans.

Don't flush anything. Change the filter and fluid in the pan.

Did the ghost of Oral Roberts happen to touch your Impala this winter....sound like a cure to me. Any way to drain the converter? How ya doing DHS??

Taking VDR and Car Back To Dealer Today...
 

Haha! I am not sure on that. They told me when I take the pan off that it will only drain about 45% to 55% of the fluid and I still have all that other fluid up in the transmission, which sounds like it makes sense. Does that sound right to you? I am doing very good, thank you.

Trans fluid is very dark to an almost black, but does not smell burnt at all. I doubt it will come to buying a new trans just from changing out the trans fluid. I have been told by a couple mechanics who do various engine and tranny work on a daily basis, not to touch the transmission fluid if there is nothing wrong with the transmission or if the fluid looks and smells alright and told not to flush it with a flushing solution. When I took it home from the Chevy dealer last Tuesday, it ran like a swiss watch. I could not get it to act up at all and neither could the Chevy dealer when they tested it. Then my fiance took it to work on Wed. or Thu. of last week and it was shifting quick and bucking and jerking at least half a dozen times on the way home when she pulled out from a traffic light or stop sign. I seriously think all that is wrong is the Solenoid Pressure switch keeps turning on and staying on due to it being bad and that has to be replaced. Hopefully the Vehicle Data Recorder they hooked up caught it.

I don't think it has gotten to the point of a lost case... yet. No damage has been done to the transmission... yet. I caught it just when the problem started and parked it for the winter till now so I could go get it fixed. Worst case I think at the moment is maybe a torque converter issue as well. I don't think it has got any worse than that yet. Anyway, when they change the trans fluid, they are not back flushing it. They said the machine just pushes out the old fluid and then replace it with the new fluid once all is put back together. I told them I was very unsure about having it done due to particles getting back up into the transmission or the film that builds up on it getting cleaned off. He said they don't flush or back flush it like some oil & Tranny quick change places do. Anyway, if the solenoid has to be replaced, the fluid has to come out. If in the end, months down the road the tranny has to be replaced after all that I am doing now fails to cure the issue, then I will buy a newly rebuilt tranny. Well, I am due to take it back today so wish me luck everyone. I will let you know how I make out in this thread. As always, thanks for all the advice.

Back in the olden days, there was a plug on the torque converter (or a stamped place to drill and tap a drain hole). Now-a-days who knows? If you can afford it I hear the synthetic stuff (tranny fluid) Dextron VI won't break down under intense heat. But remember, I'm old and not a mechanic or automotive tech and could be talking through my a** on this. Good to hear from you and stay in touch.

Fred