Put this in Drivetrain and didn't get any responses....

Car originally came with 3.23 gears, and with my current heads/cam combo I have run as fast as 12.26 @ 110mph.

Since installing 3.73s in the spring, the car has not shifted right from 2-3 at WOT.

What happens is it gets to the 2-3 shift and it will act almost like its hitting the rev limiter...studder, then shift. It is NOT the rev limiter as that is set at 6300rpm and the shift should be occuring around 6050rpm. I tried upping the limiter all the way to 6500 and dropping the 2-3 shift by 6mph that night at the track and it STILL studdered.

I had scaled the shift tables using LT1 edit, and was concerned I had some errors in the tables, so I went as far as to manually enter the values in the tables 1 at a time. At the track in March I managed only 12.50s all night at 109mph. SLOWER than with the taller gear last fall.

After that, it seemed to shift fine on the street. Yesterday I went to the track and it shifted jsut fine the first time, but my ET was a dissappointing 12.54 @ 107. There was a pretty strong headwind costing most guys 2mph in trap speed, so lets call it 12.53 @ 109.

I am flat out not getting the HP to the wheels I should be. NOthing has changed in the motor, the only change is the gears. THe trans seems to shift OK when its cold or cool, and when it gets hot is when it starts to studder.

I have a Vig 2800 and B&M tranny cooler. I've had those two items in for nearly 3 yrs and am just now having the problems since the gear install.

What is the issue here? Something mechanically wrong with the trans? Could it be slipping in 3rd gear enough to cost me ET/mph and not really be noticeable to me?

 

my tranny does something like that on the 1-2 and 2-3 shifts pissed me off, but my driveline and programming is still stock, just doesnt want to shift

 

My car does the exact same thing on each WOT gear change, if I shift a little lower it shifts fine, but if I hold it for even just 100 more RPM or so (factory tack) it snorts bucks and stutters before it shifts. What is really weird is even if I shift early it still climbs about 300 rpm more before shifting (fine). If I shift it at the 300 rpm higher manually it acts up.

I want to shift it around 6500, but I have to shift at 6200 or so for it to shift right.

 

It could be alot of different things. From what You said we can rule out programming. I would start with checking line pressure and the soleniods. Steven

 

Chris...Mine started doing that in My car...I had it pulled out and looked at...the 2-3 clutches were toast.....But hopefully thats not the case here ...Check the above first and see if you can't find another solution...Just my experience here.....BTW ....we did have a killer head wind.....No doubt....

 

All of you are experiencing the same problem...Not enough clamping force on the 3-4 clutches at high RPM's. Fortunately, I know how to fix this.

Frank
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