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Transmission Issue - 2011 Impala LT 3.5L - Please assist

21K views 8 replies 8 participants last post by  The MexKing  
#1 ·
Thank you in advance for taking the time to try to help me figure this problem out

I'm new to the forum. Hello everyone, my name is a Chris and I am in Arkansas.
This is my first post so I wanted to introduce myself.

I have done a lot of research on this forum and all over the internet trying to figure this out.
I have seen many people with shift solenoid problems. Some explain their issue that seems kinda like what I am having problems with but not exactly.

So here is what it is doing.

When the transmission is cold it functions fine for about 10 minutes of stop n go driving. But once it warms up the problem starts.

With the shifter in D and attempting to accelerate from a dead stop occasionally the engine rpm will increase but the transmission isn't transferring power from the engine to the wheels. This happens for like 2 seconds. Then the transmission will engage suddenly and I am able to accelerate and it quickly shifts into 2nd and into 3rd normally.

I am able to bypass this issue if I just manually put the transmission into 1st before I try to accelerate. Then shift into D
If I do that then it doesn't matter how hard or softly I try to take off. It functions perfectly.
I cannot reproduce the problem when I take off with the shifter in 1. Only happens when I try it while in any other gear position.

Okay that's just half of the problem.
Like I said it functions normally from 2-3 with it in D.
But then it refuses to shift from 3 to 4.

I figured out a solution to this though. My solution is something that may be a clue to exactly what the problem is. I just don't know enough about electronic transmissions to know. I am hoping that someone who is kind enough to still be reading this might know.

Okay the solution to the transmission refusing to shift from 3-4 is weird.
If I accelerate to a speed in which the transmission would normally have shifted into 4th gear. Roughly 35mph at least under average normal engine speed/normal acceleration. If I turn the Ignition off completely at speed, and then immediately turn the key back to the run position, the engine will start back up on its own. When doing so it seems that at that point the computer senses the speed at which the car is moving and then shifts then transmission into 4 immediately without issue. Then there are no issues after that.
It will even downshift to 3rd if I attempt to accelerate quickly and back into 4th when I let up on the gas pedal. Just like normal.

Given the fact that when I turn the Ignition back on while at speed and the computer shifts it into 4th without issue, it makes me think it's something other than a bad solenoid.

When I slow the car back down to a stop and then start to drive again the issue happens again.

Anyone have any ideas as to what the problem is? Or any advice on thing I should check or try to do to remedy the problem?

BTW, I know this was a long post. I appreciate you for taking the time to read this in an attempt to help me. Seriously, thank you.
 
#2 ·
Oh, just wanted to add that the car has 211k miles. But the engine sound and runs perfectly as if it had 10k miles on it.

My mother purchased it new and maintained it very well.
The Trans fluid and filter was changed at 125k miles. I bought the car from her at 155k miles and up until about 206k miles the transmission worked perfectly. Since acquiring the car I have driven it normally, not really been hard on it. There were a few road trips where I drove it at 90 or so for a couple hundred miles but that's the extent of the abuse it has had. She probably never got it above 75mph.
The majority of the miles were highway miles. With city miles being a low average.

Thanks again!
 
#4 ·
I think you are lucky to get to 200,000 miles on an original tranny from back then, no matter how well maintained it is. The Tranny has generally been the weakest link when it comes to the drivetrain on Ford, GM, and Chrysler Corp vehicles. Though I do think it has improved over the years. Crapota and Honda of course tend to over-engineer everything which earned them their good solid reputations from the late 80s on, but even they have issues from time to time. With those kinds of miles, i'd be looking at a tranny rebuild.
 
#5 ·
Chris,

I believe you have the 4T65E transmission in your car. All of the Impalas from 06-11 had some variation of the same transmission. One of the challenges reported with the transmission relates to fluid issues with the shift solenoids. Your symptom of occasional delayed 1st gear engagement from stop has been linked to a problem with the electronic pressure control (EPC) solenoid. Reportedly the solenoid becomes magnetized, becomes contaminated with iron particles, and subsequently causes erratic behavior like you describe. It may well be that it, or a combination of multiple issues with other solenoids could be causing your problem. I understand that you feel it is unrelated to solenoids, but it sounds entirely plausible to me.

What I would suggest it take it to a good transmission shop and let them diagnose he problem for you. Unfortunately, you are likely looking at some type of work to rectify the problem. While the cost of the solenoids is not too bad, the labor to replace them is pretty steep. That and I am not sure it would be wise to invest that much into a 200k mile transmission.

Best of luck to you.
 
#6 ·
The key to preventing problems like this is more frequent fluid and filter changes. Doing first fluid and filter change at 120k miles is too late in my opinion. I do mine every 40 k miles and I bought my car new and now it has 208k miles with no transmission problems.
This of course will not help your case now. Most likely you will need to replace shift solenoid as they are likely contaminated with metallic dust in oil due to normal wear and failure to change the fluid for along time.

These transmissions are not that expensive to replace. A rebuild one from GM is only about $2k. But installation will be another $1k unless you can do it yourself.