LS2__GTO

i have a 2006 Pontiac Gto, and last week i had 3rd and 4th go out.
so without thinking i bought a rebuild kit and rebuilt the transmission, after i rebuilt it, changed out the solenoids and fluid the car still does the same thing.
1st and 2nd are fine, when it trys to shift into 3rd it revs freely like its in neutral.
ive seen threads about this issue many times, but i still cannot find the exact issue to fix it.

Anyone else having the same issue or know what the problem could be?

Thanks.....

mrvedit

Did you air test the 3/4 clutch after assembling the input drum?
And again placed into the pump for a test?
Did you carefully check that the input shaft is tight in the input drum and not leaking?
Did you test the 3rd accumulator check ball cartridge for leakage?
How much clearance was there in the 3/4 clutch?

There are many places the 3rd apply fluid can leak and they all need to be checked during a rebuild.

performabuilt

iTrader: (25)

Agreed on checking all stuff mentions but a simple way to check mechanical function is to unplug trans harness and then manual shift the 2-3. You will not be able to get 1st or 4th gear but if the 3-4 clutch is functional you should be able to do a manual only 2-3 shift ,
Note this will set codes that must be cleared after.

Jays_SSZ28

iTrader: (2)

I take it you didn't look for the problem the first time?
When a trans has a problem figure out what it is during the first rebuild, saves time and money.

ebeard

I'm having the same issue in a k10 with an 07 5.3 and 4l60. Can command 4th with hp tuners and it will shift to 4th but telling it to shift to 3rd doesn't work, just revs freely.

mrvedit

Having 4th and not 3rd is very unusual; I would like to confirm whether you have 2nd gear. And that you are testing correctly.

With the rear wheels off the ground...
From a dead stop each time, command different gears and note the speed at e.g. 1500 RPM. I want to be sure you aren't simply overrunning lower gears because OD and D3 do not provide any engine braking as you downshift via commands - it will feel like neutral.

If you can reach the trans harness connector, removing it and tell us what gear, if any, you think you are then in. See post #3 for details.