Transmission "stuttering?" from a stop [Archive] - GrandAmGT.com Forum

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xsl_will
09-30-2009, 02:36 PM
So... sometimes when it gets real hot or if the car has been in stop and go traffic for a while, I will have transmission problems. If I apply partial throttle, the gear kind of engages and then it feels almost like wheel hop. The entire front end "stutters." And then within a second or two, it will subside and will continue to drive like normal until I stop, and then apply partial throttle to get going again. It seems that I don't usually get this problem when it's cooler out or if I apply full throttle. No dash lights. I have not had the oppurtunity to scan for codes.

Based on this, I don't think that it's any of my mounts, though I suppose it is possible.

What could it be? Bad MAF, TPS, or IAT sensor? Worn valve body?

I've done two pan drops and filter replacements in the last 8k miles. The trans has just under 75k on it.

Am I overlooking something very simple? It didn't start doing this until maybe 6k miles ago. Could I have over or underfilled the trans? Though I see fluid dripping out the sighthole with the car running. My PCM has been tuned by Mark at MPR.

icecats87
10-01-2009, 06:51 AM
Are you saying when your stopped your whole car shakes and you can feel it, when you press the throttle it shakes a little then smooths out? if so its what happened to me and my head gasket was blown. you should do a compression check on all of the cylinders the one that didn't work for me had the highest pressure.

xsl_will
10-01-2009, 01:33 PM
Are you saying when your stopped your whole car shakes and you can feel it, when you press the throttle it shakes a little then smooths out? if so its what happened to me and my head gasket was blown. you should do a compression check on all of the cylinders the one that didn't work for me had the highest pressure.

No. The car does not shake at a stand still. It's when it rolls off the line in partial throttle that it shakes. It feels a lot like wheel hop. If I floor it, it seems to be fine.

icecats87
10-01-2009, 06:09 PM
Oh ok yeah what it sounded like what was wrong with my car but mine was shaky at a stop and halfway through a turn then white smoke was coming out of my exhaust, which was the coolent being burned through the gasket break but i got the parts for about $500 and me and my uncle took apart the whole engine to fix it for free some shops wanted $1,500

AleroB888
10-01-2009, 06:30 PM
No. The car does not shake at a stand still. It's when it rolls off the line in partial throttle that it shakes. It feels a lot like wheel hop. If I floor it, it seems to be fine.

I hate to say it, but that was the first symptom of my tranny going out, but mine started doing it worse in reverse gear. Then it seemed to clear up for awhile. Mine finally just would not upshift at wide open throttle, first once from third to fourth, and now from first to second, getting caught between gears and overrevving. Now the shaking/wheel hop stuff is gone, but it doesn't shift right, also at part throttle, and makes a horrendous clattering sound over 1800 rpm.

Now there is a very, very remote chance a PCM issue can cause similar symptoms, I had one experience like that before, but that was due to a reflash of the PCM that failed for some reason.

xsl_will
10-01-2009, 10:28 PM
I hate to say it, but that was the first symptom of my tranny going out, but mine started doing it worse in reverse gear. Then it seemed to clear up for awhile. Mine finally just would not upshift at wide open throttle, first once from third to fourth, and now from first to second, getting caught between gears and overrevving. Now the shaking/wheel hop stuff is gone, but it doesn't shift right, also at part throttle, and makes a horrendous clattering sound over 1800 rpm.

Now there is a very, very remote chance a PCM issue can cause similar symptoms, I had one experience like that before, but that was due to a reflash of the PCM that failed for some reason.

Mine only does it in first off the line. It seems to be okay if I put the gear selector in "1." There was one time that the trans was slipping in the middle of third. Lots of revs, but no more accleration. The trans shifts fine at WOT. And it doesn't seem to be making any strange noises.

For a while I thought that it was the trans going out... but now I'm not so certain.

02silverstreak
10-01-2009, 10:43 PM
I don't know too much about the electrics on a GA but could the ETS have something to do with it.

DoCDooM
01-02-2010, 11:10 AM
When you get some kind of useful information please let me know, I have the same problem and sometimes the engine revs under light throttle going up OR down a slight hill.

I'll let you know as well, the tranny appears to be fine and the problem is intermittent and only happens on cold or damp days.
"GM, there is no excuse"

ryanbgb22
01-02-2010, 02:27 PM
It just sounds like your transmission is starting to slip to me.

GA2000GTSpeed
01-02-2010, 02:40 PM
Well whens the last time you changed your trans fluid? the easiest way to check to see if its going out is to take off the trans pan and see if theres metal shavings or anything at all in the pan, and if the fluid smells burnt. but if you have done this recently i can see u not wanting to pay for all that fluid again lol

But it will most likely rule out the trans, and if you haven't had you codes scanned, you should as soon as you can, I know one of the things we get taught is that the service lights could just be burned out (even though this always seems unlikely).

xsl_will
03-11-2010, 07:38 PM
Trans fluid and filter was changed twice in the last 6000 miles. Once was with Dexron VI, the other with Amsoil ATF. No metal, did not smell burnt.

No service lights, no codes pulled, but have not had transmission diagnostics. I have not been driving the car the last few months. I'll see if I can run a diagnostic.

No ETS on my Malibu, so that's not an issue.

PCM would be interesting... but PCM was tuned by Mark about 2 or 3 years ago, this problem just started recently.

Mike Jung
03-11-2010, 07:56 PM
Misfiring ?

How are the Spark Plugs & Wires ?

xsl_will
03-11-2010, 07:58 PM
No misfires recorded.

NGK Iridium Plugs and MSD 8.5mm wires about 6k ago. Plugs do not appear to be fouled.

Malaclypse
03-11-2010, 08:56 PM
I'd say check the fluid level to see how that is. Loss of engagement or partial engagement can be caused by a low or high fluid level. Low wouldn't allow the pump to build sufficient pressure to fully apply the clutches until higher revs or a lower gear were selected, High fluid could cause issues due to aeration. Another cause for aeration may be damage to the filter seal where it goes into the trans valve body.

If the fluid level is fine there may be issues with the friction modifiers in the Amsoil fluid you put in. Sure the fluid may say it meets all of GM's specs, but transmissions can be picky sometimes. The fact that your transmission has higher mileage on it may also have something to do with it.

Yes, the trans could be starting to slip now.. but with two fluid changes in the past 6k (very excessive), you've added two different fluids. This makes a mixture of three fluids floating around in your transmission as you can't get everything out of the torque converter. It may have made an interesting mix of friction modifiers in your transmission and could be causing clutch issues.

Basically, there are no guarantees against internal damage, but the cheapest solutions to try first are to check the fluid level, go back to Dex VI and replace the filter seal.