99' Monte Carlo 3.1

[KdogTN]

I'm having a transmission problem and wanting to possibly get some ideas.

It's a Monte Carlo 3.1 with 170k miles on it. I had a transmission flush performed at about 80k and again at about 160k. Almost all of these miles are highway miles. I noticed the other day that on the highway I was turning up over 3k rpms at about 70 mph. That seems a bit high for me. It goes through the gears without fault but it feels as if when it goes into third, it makes its way into fourth but there is very little RPM change. When I am no the highway doing 70mpg, I can take it from overdrive back into D and the RPM's maby go up 100 but not enough to make a difference. When I take my foot off of the throttle the rpm's drop to idle until I give it gas again and they race back up to 3000k or so before engaging and driving the car forward again. Also, for some reason now, when I am driving in town and at about 30 mph, it argues within itself what gear it should be in. It pulls strong on a take off and doesn't seem to hang between gears. I put a computer on it and this is what I have been able to see. At 70mph the slip is at about 800rpm's. I watched the shifting action between 1-2 2-3 and they are going from on to off. For some reason my computer will not show a 3-4. I have no leaks and the fluid looks like it was just changed. I am not sure what else I need to look for on here. The motor of the car is in perfect condition never going more than 3k miles between oil changes. I would really like to keep this car in service but if it looks like I'm about to detonate a transmission it's time to go.

[wafrederick]

You made a huge mistake,getting your transmission flushed with the machine and you are looking into a new transmission.GM does not recomend flushing a transmission and it says in the factory service manual.The best thing to do is change the fluid and filter in an automatic transmission.

[blazes9395]

Are you getting TCC lock -up? Are you getting any service codes popping up? 800 rpm is too much, either your not going into 4th gear, 4th is slipping, or your not getting a TCC lock-up.

I agree with wafrederick, getting a flush is not always the best idea. Sometimes it can cause more harm than good.

[wafrederick]

I know a transmission shop that does valve body cleanings due to someone getting their transmission flushed and my father has seen this happen while visiting to get a part for a transmission or advice on a transmission problem.Dirt gets stuck in the valve body when it is flushed and you do not want that.I had to replace one transmission in a 1998 Monte Carlo due to being flushed.It was acting up,repaired it once and did not fix it.