AT trans seem very rough
Thread Starter
Instructor
Joined: Oct 2012
Posts: 134
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From: Fl
AT trans seem very rough
Now before I list supposed symptoms, this is not only my first V8 but first american car so I'm not sure if I'm just being paranoid.
I have a 99 with 49k and In my opinion it seems to be shifting very hard, even when I'm just cruising around barely touching 1600rpms.
Last night I gas'd it at about 60 and experienced a very rough shift.
My last car was a 06 350z at with alittle over 300whp, so it could just be rough to comparison.
So I guess my question is if the vette trans is meant to feel like a racecar because then Id understand the hard shifting, or is it just because its a 99 v8 and I'm used to newer hirev 6's???
I've also heard mixed reviews about having a tranny service, some say it can make things worse but I'm defintely willing to do it asap.
I have a 99 with 49k and In my opinion it seems to be shifting very hard, even when I'm just cruising around barely touching 1600rpms.
Last night I gas'd it at about 60 and experienced a very rough shift.
My last car was a 06 350z at with alittle over 300whp, so it could just be rough to comparison.
So I guess my question is if the vette trans is meant to feel like a racecar because then Id understand the hard shifting, or is it just because its a 99 v8 and I'm used to newer hirev 6's???
I've also heard mixed reviews about having a tranny service, some say it can make things worse but I'm defintely willing to do it asap.
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Now before I list supposed symptoms, this is not only my first V8 but first american car so I'm not sure if I'm just being paranoid.
I have a 99 with 49k and In my opinion it seems to be shifting very hard, even when I'm just cruising around barely touching 1600rpms.
Last night I gas'd it at about 60 and experienced a very rough shift.
My last car was a 06 350z at with alittle over 300whp, so it could just be rough to comparison.
So I guess my question is if the vette trans is meant to feel like a racecar because then Id understand the hard shifting, or is it just because its a 99 v8 and I'm used to newer hirev 6's???
I've also heard mixed reviews about having a tranny service, some say it can make things worse but I'm defintely willing to do it asap.
I have a 99 with 49k and In my opinion it seems to be shifting very hard, even when I'm just cruising around barely touching 1600rpms.
Last night I gas'd it at about 60 and experienced a very rough shift.
My last car was a 06 350z at with alittle over 300whp, so it could just be rough to comparison.
So I guess my question is if the vette trans is meant to feel like a racecar because then Id understand the hard shifting, or is it just because its a 99 v8 and I'm used to newer hirev 6's???
I've also heard mixed reviews about having a tranny service, some say it can make things worse but I'm defintely willing to do it asap.
The first thing to do is to check the transmission fluid level. There is a procedure in the sticky, at the top of this forum section, that explains how to check the transmission fluid level. http://forums.corvetteforum.com/c5-t...uid-level.html
If you are not the first owner, someone may have previously installed a "shift kit", or had the PCM tuning parameters modified, for firmer shifts.
Last edited by Quicksilver Vert 01; Oct 7, 2012 at 08:09 AM. Reason: Added link
Thread Starter
Instructor
Joined: Oct 2012
Posts: 134
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From: Fl
The shifts should be somewhat on the firm side, but not harsh or rough like you have described.
The first thing to do is to check the transmission fluid level. There is a procedure in the sticky, at the top of this forum section, that explains how to check the transmission fluid level.
If you are not the first owner, someone may have previously installed a "shift kit", or had the PCM tuning parameters modified, for firmer shifts.
The first thing to do is to check the transmission fluid level. There is a procedure in the sticky, at the top of this forum section, that explains how to check the transmission fluid level.
If you are not the first owner, someone may have previously installed a "shift kit", or had the PCM tuning parameters modified, for firmer shifts.
I doubt any kit or tuning was done.. Only mod on the car is flowmaster axleback. But if so is it a bad thing? Will it shorten the life?
I'll check out the sticky, but I'll probably just take it to the dealer and have the trans serviced just for the hell of it.. I have a warranty (somehow) so if they F it up or there is something wrong with it I'm covered. Figure the cars 13 years old, even though its low mileage the fluid has to be questionable by now especially since its probably never been serviced.
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Unless the car will be used for competitive racing, I would personally not make any modifications to the transmission.
Thread Starter
Instructor
Joined: Oct 2012
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From: Fl
Nah, I'm not a track guy.. too much abuse for my wallet to handle. I just like to get on it every now and again, and friendly top end race is nice when it presents itself.
If it does have something done to it Id like to go back to stock. Otherwise tranny service it is.. I was just wondering if the roughness was common.
Safety Car
Joined: Aug 2011
Posts: 4,449
Likes: 409
From: Portland OR
It would be interesting to pull the DTC's from the Driver Information Center. There are a few that could command full line pressure from the trans and make it shift hard.
Do you know how to do that?
Ron
Do you know how to do that?
Ron
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
One of the better code scanners, that are capable of sampling real-time operational data, might allow you to read the actual line pressure.
I believe a Tech II tool can also read and adjust the line pressure values.
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Melting Slicks
Joined: Jun 2012
Posts: 3,163
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From: Oceanside California
I would take it in for a tranny and differential service asap. It probably has never been done. The good news is that the service interval is 75k-100k miles. So you are not due for a change even if it was driven rough. The worry about servicing trannys comes from higher mileage vehicles when the fluid is bad from neglecting ever changing, then new fluid can cause leaks and solenoids to wipe out etc.
So IMO at the first sign of any transmission problem, take it in for an inspection/ service. (new trans fluid/ filter, and diff fluid.) It sounds like its had some abusive owners in the past. But it may be savable.
A transmission specialty shop can test drive it for you and tell you exactly whats going on too. I know you have a warranty where you got it, so its your call. The dealership loses money off of warranty work, so they are much more likely to pass it off as being fine and not to worry about it.
So IMO at the first sign of any transmission problem, take it in for an inspection/ service. (new trans fluid/ filter, and diff fluid.) It sounds like its had some abusive owners in the past. But it may be savable.
A transmission specialty shop can test drive it for you and tell you exactly whats going on too. I know you have a warranty where you got it, so its your call. The dealership loses money off of warranty work, so they are much more likely to pass it off as being fine and not to worry about it.
Safety Car
Joined: Aug 2011
Posts: 4,449
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From: Portland OR
Yes, correct. The codes that raise line pressure should turn on the MIL. But, no guarantee someone didn't change the programming.
My A4 slammed the 1-2 shift when I bought the car. After a scan with HPT, P1870 Transmission Component Slipping had been set to no report.....
P0101, P0102, P0103 all set trans line pressure to max.
Just somethung to check, I had no idea someone had "been in there". It was very revealing.
Ron
My A4 slammed the 1-2 shift when I bought the car. After a scan with HPT, P1870 Transmission Component Slipping had been set to no report.....
P0101, P0102, P0103 all set trans line pressure to max.
Just somethung to check, I had no idea someone had "been in there". It was very revealing.
Ron
Tech Contributor
Joined: May 2008
Posts: 3,100
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From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Most transmission shops might even overlook that possibility before delving into a major (and expensive) rebuild.
Instructor
Joined: Nov 2011
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Check it for codes 1870 will make a harsh 1-2 most common for the code is a worn torque converter regulator valve in the valve body but can be fixed without removing the trans fits all makes a valve that doesnt require valvebody machining trans service is good preventave maintance just do a filter and fluid change dont do the flush .Donot alter the line psi threw the pcm to solften the shifts if u want a smoother 1-2 order the 1-2 accumlater springs for a s10 this will solften low speed shifts
Drifting
Joined: Jul 2001
Posts: 1,312
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From: Lake Havasu City AZ
Ok. The car only has 49K on it and it isn't showing any codes. I would say either shift kit or tuning. If you take it to dealer, they can tell you if the trans code has been changed and if there are any history codes. If they changed the program and upped the hydraulic line pressure, have them change it back.
If its none of those than its a shift kit and a good trans shop should be able to reverse the harshness by installing the standard springs in the actuator accumulators. The price to check the code shouldn't be over one hour dealer cost. The price for installing new springs shouldn't be more than 2 hours shop time and every trans shop should have the springs or go to another shop. If you have them do the springs, change the filter and install a new trans pan with a drain plug.
Good luck.
Mike V
If its none of those than its a shift kit and a good trans shop should be able to reverse the harshness by installing the standard springs in the actuator accumulators. The price to check the code shouldn't be over one hour dealer cost. The price for installing new springs shouldn't be more than 2 hours shop time and every trans shop should have the springs or go to another shop. If you have them do the springs, change the filter and install a new trans pan with a drain plug.
Good luck.
Mike V
Last edited by MikeV; Oct 8, 2012 at 04:17 PM.