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Discussion Starter · #1 ·
Hi all,
I have a problem with my transmission that nobody can figure out for me and Im hoping somebody here has an idea. I purchased the 07 impala 3.5 new and the transmission worked fine until 105k. It very intermittently wont release a higher gear when I come to a light. When I go to take off from the light the car moves very slowly forward (Not slipping, but rather in a high gear so it cant move) and bam it downshifts and takes off. It happens about once every 350 miles. The other times the trans shifts as it were brand new.

Background info:
I changed the fluid and filter at 50k and 110k with gm filter and gm fluid (which is crazy expensive) both times I disconnected a line and pumped the old out and poured in new and repeated until clean came out of the line. (about 20 quarts!)

The car was only driven on the highway from Cleveland to Detroit daily.

There are no codes in the computer, 2 GM dealers, 2 local tranny shops, and a local aamco checked out the car for the problem and dont know how to fix it.

I looked at all the TSBs with the dealer and none of them describe my problem...

The car now has 155k on it and the problem hasnt gotten any worse, hasnt changed, and hasnt gone away.

The GM dealer suggested a new trans for $3,000, but it shifts like new other than the once every 350 miles, and sometimes it does it 4 times on one trip and not for a month. There is no pattern at all. It does it stone cold, hot, around town, just whenever.

Everybody talks of a slipping out of gear at N problem on this forum, but this definitely is stuck in a higher gear at take off. The car growls very slowly forward for about 5 feet (2 seconds of time elapses and the tach doesnt rise) and bam, into first and away it goes.

Aamco suggested a computer reflash? this doesnt make sense to me, but they said the tranny shifts perfect so it has to be something like that...

This car has been terrible, headgaskets, intake manifold, front seal, ac compressor, wheel bearings, purge valves, oil pan gasket, both front speakers, vent solenoids, control arm bushings, rack leak, power steering pump shaft leak, rear main seal, and the tranny problem that nobody can fix...thats just off the top of my head...

Any ideas?

Thanks,
 

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New car, when it start have you tried to manually shift car into 1st?
Sound like solenoid sticking but we have some trans guys on here that should be able to help.
 

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Discussion Starter · #3 ·
I tried shifting manually to first every time while I was sitting at a light and it did not act up. I did this for a few days. But, since the problem only happens like once a week, maybe it just didn't act up in that time frame...
 

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This is the typical problem. I believe many have done solenoids and it fixes it.

I have 2 Impala's that do this at very irregular times. One of them started it at 75K miles, and with 230K now, haven't done anything, just live with it. It actually rarely does it now with the higher miles, so saying it needed a rebuild at the 75K mark is BS, unless you like perfection.

To say you need a rebuild is probably not true, but sometimes, depending on labor required, you might as well. TO me a rebuild implies, you wasted clutches, steels, and seals, which is seldom the case.

Low fluid level does this as well. I wish I knew an additive to help the solenoids, and I may try one in my 08, but it only happens once a week or so.
 

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I had problems very similar to what you describe. My 2006 LTZ has 85K. I first had the filter replaced and added fluid that was lost dropping the pan. Everyone in here says to NOT do a tranny flush. I added a 12 oz bottle of Marvel Mystery Oil. I have had the tranny act up only once in 7 months so I don't even worry about it. Marvel Mystery Oil is ok to add to tranny but no more then 12 oz and do not over fill tranny. This stuff is the best for unsticking things that are stuck.
 

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My car is doing the exact same thing after I got the trans rebuilt. I have a warranty on the rebuild so its going back to him today plus my fluid is constantly low. I posted my problem on here and someone asked if he used the same torque converter so that may be the problem. As far as the fluid being low I was told that the trans cooler may be leaking the engine coolant since the trans cooler is inside the radiator.
 

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My '06 LT tranny did that for a while and finally went out on me completely on the on-ramp to the interstate this past March. Cost me roughly $3K to fix.
 

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Hi all,
I have a problem with my transmission that nobody can figure out for me and Im hoping somebody here has an idea. I purchased the 07 impala 3.5 new and the transmission worked fine until 105k. It very intermittently wont release a higher gear when I come to a light. When I go to take off from the light the car moves very slowly forward (Not slipping, but rather in a high gear so it cant move) and bam it downshifts and takes off. It happens about once every 350 miles. The other times the trans shifts as it were brand new.

Background info:
I changed the fluid and filter at 50k and 110k with gm filter and gm fluid (which is crazy expensive) both times I disconnected a line and pumped the old out and poured in new and repeated until clean came out of the line. (about 20 quarts!)

The car was only driven on the highway from Cleveland to Detroit daily.

There are no codes in the computer, 2 GM dealers, 2 local tranny shops, and a local aamco checked out the car for the problem and dont know how to fix it.

I looked at all the TSBs with the dealer and none of them describe my problem...

The car now has 155k on it and the problem hasnt gotten any worse, hasnt changed, and hasnt gone away.

The GM dealer suggested a new trans for $3,000, but it shifts like new other than the once every 350 miles, and sometimes it does it 4 times on one trip and not for a month. There is no pattern at all. It does it stone cold, hot, around town, just whenever.

Everybody talks of a slipping out of gear at N problem on this forum, but this definitely is stuck in a higher gear at take off. The car growls very slowly forward for about 5 feet (2 seconds of time elapses and the tach doesnt rise) and bam, into first and away it goes.

Aamco suggested a computer reflash? this doesnt make sense to me, but they said the tranny shifts perfect so it has to be something like that...

This car has been terrible, headgaskets, intake manifold, front seal, ac compressor, wheel bearings, purge valves, oil pan gasket, both front speakers, vent solenoids, control arm bushings, rack leak, power steering pump shaft leak, rear main seal, and the tranny problem that nobody can fix...thats just off the top of my head...

Any ideas?

Thanks,
Hey did you ever figure out the problem with the tranny? I am having the same problem on my impala and no one will help me!!
 

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I had a 2004 Buick Regal that would do that exact same thing. Slam into gear when first going forward after shifting from reverse and once in a while it would slam when taking off at a stop light. It would happen once a month to once a week at times. Never fixed it, just lived with it until I sold the car. I did find that on a section at tripleedgeperformance.com they found that the issue is the worn surface of the input clutch piston. See here No Forward Cold
My 2008 Impala that I own now, currently with 81K on it, only does the slamming maybe once a month when cold when going from reverse to drive out of my driveway and I am not too concerned about it yet.
 

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pressure control solenoid bracket

07 chevy impala transmission pressure control solenoid bracket
The transmission pressure control solenoid may fail causing erratic shifting. A partial dis-assembly of the transmission is necessary to replace a failed pressure control solenoid and or bracket. Just to let you know what we found, when we lowered the tranny down and pulled the side cover off that faces the left front wheel and I replaced the pressure control solenoid and bracket. And while I was in there I replaced the torque convertor band with solenoid just because these go bad often also but the problem was the pc solenoid, it now works great and I have no problems
 

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07 chevy impala transmission pressure control solenoid bracket
The transmission pressure control solenoid may fail causing erratic shifting. Our technicians tell us that partial dis-assembly of the transmission is necessary to replace a failed pressure control solenoid. Just to let you know what I found . I lowered the tranny down and pulled the side cover off that faces the left front wheel and I replaced the pressure control solenoid. And while I was in there I replaced the torque convertor band with solenoid just because these go bad often also but the problem was the pc solenoid, it now works great and I have no problems
Just to let you know what I found . I lowered the tranny down and pulled the side cover off that faces the left front wheel and I replaced the pressure control solenoid. And while I was in there I replaced the torque convertor band with solenoid just because these go bad often also but the problem was the pc solenoid, it now works great and I have no problems
 

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Shift solenoids for 1st gear only

https://www.impalaforums.com/8th-gen-drivetrain/diy-do-i...r-removal.html, its the shift solenoids, i had the same problem with 05 ls 3800 series II, i changed them and it was like new again. its the same transmission from 2000 - 2011. so dont worry about the model. so check out that link.
I don't have the high-gear lock up problem, but any time we accelerate from a stop with any gas pedal pressure greater than 25% it slams down into first. If I feather the gas pedal down to 50% over about 2 seconds it's smooth as silk, and I'm still not holding up traffic. Then I can push it from there to the floor and we smoothly rocket ahead.

Does that sound like a solenoid? Something is sticky, it seems to me.

EXTRA QUESTION: A good mechanic told me years ago that the little bottle of limited slip differential additive (from GM, I think) would be a fairly long-term fix for a slipping tranny. I thought it was called something like "PosiTrac" when I bought the first one. I put it in my Plymouth van, and in 100 km the rough shifting problem disappeared. I went back to buy a couple more for future need (about $10 a bottle), and the bottle says ACDelco Limited Slip Differential Lubricant Additive. Anybody heard about this trick?
 

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I don't have the high-gear lock up problem, but any time we accelerate from a stop with any gas pedal pressure greater than 25% it slams down into first. If I feather the gas pedal down to 50% over about 2 seconds it's smooth as silk, and I'm still not holding up traffic. Then I can push it from there to the floor and we smoothly rocket ahead.

Does that sound like a solenoid? Something is sticky, it seems to me.

EXTRA QUESTION: A good mechanic told me years ago that the little bottle of limited slip differential additive (from GM, I think) would be a fairly long-term fix for a slipping tranny. I thought it was called something like "PosiTrac" when I bought the first one. I put it in my Plymouth van, and in 100 km the rough shifting problem disappeared. I went back to buy a couple more for future need (about $10 a bottle), and the bottle says ACDelco Limited Slip Differential Lubricant Additive. Anybody heard about this trick?
I wouldn't recommend it. Dave at TEP says the Lucas additive works but I'd just replace the shift, TCC, and pressure control soelnoids along with adding the pan magnets GM called for in the TSB.
 

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Hi all,
I have a problem with my transmission that nobody can figure out for me and Im hoping somebody here has an idea. I purchased the 07 impala 3.5 new and the transmission worked fine until 105k. It very intermittently wont release a higher gear when I come to a light. When I go to take off from the light the car moves very slowly forward (Not slipping, but rather in a high gear so it cant move) and bam it downshifts and takes off. It happens about once every 350 miles. The other times the trans shifts as it were brand new.

Background info:
I changed the fluid and filter at 50k and 110k with gm filter and gm fluid (which is crazy expensive) both times I disconnected a line and pumped the old out and poured in new and repeated until clean came out of the line. (about 20 quarts!)

The car was only driven on the highway from Cleveland to Detroit daily.

There are no codes in the computer, 2 GM dealers, 2 local tranny shops, and a local aamco checked out the car for the problem and dont know how to fix it.

I looked at all the TSBs with the dealer and none of them describe my problem...

The car now has 155k on it and the problem hasnt gotten any worse, hasnt changed, and hasnt gone away.

The GM dealer suggested a new trans for $3,000, but it shifts like new other than the once every 350 miles, and sometimes it does it 4 times on one trip and not for a month. There is no pattern at all. It does it stone cold, hot, around town, just whenever.

Everybody talks of a slipping out of gear at N problem on this forum, but this definitely is stuck in a higher gear at take off. The car growls very slowly forward for about 5 feet (2 seconds of time elapses and the tach doesnt rise) and bam, into first and away it goes.

Aamco suggested a computer reflash? this doesnt make sense to me, but they said the tranny shifts perfect so it has to be something like that...

This car has been terrible, headgaskets, intake manifold, front seal, ac compressor, wheel bearings, purge valves, oil pan gasket, both front speakers, vent solenoids, control arm bushings, rack leak, power steering pump shaft leak, rear main seal, and the tranny problem that nobody can fix...thats just off the top of my head...

Any ideas?

Thanks,
Rebuild it
 
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