Renegade

iTrader: (1)

Well I took my car to the local drag strip tonight, which happens to be an extremly slow track due to prep and such... most guys run .5 slower then at other tracks... but am still a bit disappointed. The car is bouncing off the Rev Limiter two-three times shifting from 2nd to 3rd at WOT, if you let off it will shift quicker, but if you just keep it floored it will keep bouncing. I cut a .117 RT, 2.2 60 ft. and a 9.254 1/8 Mile, but when the car bounces off the limiter I'm thinking I'm losing quite a bit of time, my 1/4 was 14.189 @99. The fluid looks good and the tranny only has 65k miles on it, just wondering if anyone figured this could be computer related or if something was wearing out? I'm thinking I should have ran a bit faster and broke 100 if it wasn't bouncing for a couple seconds.

Any help would be greatly appreciated .

1bad71

my t/a did the same thing! had it tuned and had the shift points reset and boosted the line pressures.

find your local tuner and have a dyno pull also, will make a "big" difference.

wvutransam

Hope he is right but I doubt it. Mine did the same exact thing. Within about 2 weeks it wouldn't shift into third over 3k rpms. Took it to GM under extended warranty and came out with a new tranny...

Armyman2445

iTrader: (17)

IT's not a problem with the transmission as a whole. Mine did that with the old and new trans. The problem is your speed sensor is going bad or is bad. I thought it was the transmission itself at first, but after a good 175 shot or juice off the line well it broke. Got it rebuilt as a 4L65 and it did the same thing. Rev Limiter going from 2-3. I bought a new speed sensor for around $60 and the problem went away.

Renegade

iTrader: (1)

Speed Sensor eh? That might make sense actually, because when I go through the things that clock your speed at like 30 it says 32 etc. I don't know how accurate those are but that makes sense, I suppose the $60 is worth spending before spending 2k rebuilding. Thanks for the info, anyone else have opinions? Hoping it's not something major.

fast01

iTrader: (16)

As a police officer I can tell you that those traffic signs you're talking about are about 2 MPH off. As a 2001 Z-28 owner I can tell you that I just went through the same problem and a common one it is. Actually on Thursday I took my car to Eastside Performance and Dyno Service to sort the problem out. After some time talking with the tuner and with the tranny guy on the phone, we determined that the tranny was working correctly as far as clutches and electronics go, but the piston is not able to seal at higher RPM's. This is causing a delay in oil entering the circuit and delaying the shift even though the computer is commanding one. In this delay time the engine will rev past the shift RPM and hit the limiter. What we did to correct it was lower the commanded shift RPM and MPH and raise the rev limit for the 2-3 shift only. This seems to work and it's now shifting at 6500 RPM w/o hitting the limiter. I don't know how consistant it will be yet, but it works. Hope this helps!

Renegade

iTrader: (1)

Thanks for the info guys, basically I'm going to have to have the car dyno tuned to fix this problem?

gillbot

iTrader: (27)

I had to lower my shift points to make up for poor track prep.

PREDATOR-Z

That effect has to do with worn out clutch bands. I have the same problem with mine under nitrous. Time for another A4, this will be my 3rd in 5 years and 3 years racing.

fast01

iTrader: (16)

Mine was definately the tune. We ran some tests to see if the engine was driving through the clutches, but when they engaged, they grabbed real hard pulling around 30 hp from the motor.