strange 2-3 shift issue. rev limiter from a dig, shifts fine from a roll.

[crazyelf]

Ive been setting my shift points since the new gears are in and ive just got this left to figure out.


If i nail it and run through 1st then into second it will not shift into 3rd and hits rev limiter.

But if I nail it say 50 mph it downshifts to second and then shifts into 3rd at the commanded shift point I set.


What could cause this?

Also if I hold second to do a rolling race and shift it manually into 3rd it wont shift and hits limiter.

[mecanicman]

post the tune and a log if you have it.

[crazyelf]

I can do that later today when I get home

[crazyelf]

Here we go!
I lowered the shift rpm to 5500 to test it and got it too shift around 6100 but then rolling it shifted at 5600

[mecanicman]

Have you confirmed your speedo calibration is correct with say a gps? or anything?

[crazyelf]

according to my phone gps my speedo is off by about 1mph at 75

[98tadriver]

Im having the same exact problem with mine. everything seems to point to mechanical for me :/ Did you remove all of your torque management? a friend of mine added some tq management and it seemed to help a lil bit

[realcanuk]

Have you tried with traction control off. Is it possible you are getting a bit of tire spin which would activate TC and prevent the shift ?

[pl4yboy]

I'm having this exact issue. Only started after adding a cam and pushing the shift RPMS up to 6600 from 6000 before. First will feel like it just TOUCHES the rev limit. Two feels like it hits it good. Three literally hits it and sticks. I've zero'd the MPH tables and I'm going strictly off RPM at this time. Still doing it. Only from a dig, never from a roll.

[pl4yboy]

Anyone think this may be related to the Powerhop via spark/fuel options?

[98tadriver]

mine ended up being mechanical. had two of my buddies look over the tune. everything was good tuning wise. at the track or where you can go from a dig, no 2-3 shift @ wot is a common problem with the stock 4l60e's. mine acted up with about 85k miles on it. before i did the shift kit, i noticed when the car was cold, the 2-3 shift would flare, especially if i got on it a lil bit. I have a low mileage (23k mile) stocker with a shift kit that's going in soon. I'll let yall know how that goes. as soon as I install it, ill be sure to go to the track lol

[98tadriver]

even with the newly installed transmission, it is still doing the same thing. Im going to double check the fluid level tomorrow.

UPDATE I had some help with tuning, turns out with the corvettes, when you change the gears, you leave the stock gear number in the table alone. (reason being, the vss is in the rear, not on the trans like fbodies)then deduct the % of gear change from your current shift tables. I had 2.73 gears and went to 3.42's. i had 3.42 in the table. went back to 2.73 on the table, changed the shift points by 25% to get a baseline to work from and it helped. had a lil help with fine tuning the shift pressures and should be good to go now

[Frost]

Yeah I wish that 'wizard' was just grayed out for cars like that... so do the people buying HPTuner's from me.

[gn2beatu]

I figured it out, you forgot to change your hot shift settings. They are at 70!!

Look at your engine temperature, thats why it does it after driving it for a while and by the 4th restart, its HOT!! ;-) G/L, and PM me if it does or doesnt fix it, I dont get back to every thread, but Im about 99% sure thats it.