abdulroof-alkhoja

hi for all
anyone tel me about this delay shifting 2 - 3
my trans is 4l60e
Zpak 3-4 clutch. HD 2-4 band. shiftkit transgo HD2


i rebuild the trans also i changed all internal parts and found this problem

note
the shifting point is 6300 but the rpm jump more than 7000 then engage 3th gear

also same problem happen if i shifting manually



thanks

mrvedit

I would need to see a logging file, but it looks like there is slippage during the shift.
At WOT shifts take place when BOTH the tuned rpm -AND- the tuned MPH are reached. You only mention your shift-RPM, but not the shift-MPH.

Is the only thing you changed the trans or did you also change the tune?

I suggest you connect a trans pressure gauge to see what the line pressure is during the shift. You can buy one on Amazon for $34 - search for "ATD 5550".

What is the clearance on the Zpak?
(I don't think any pro builder/sponsor still uses the Zpak, there are better alternatives.)
How much HP is your engine putting out?

abdulroof-alkhoja

i tried more times to change the shifting point RPM and MPH no any result
today i changed 2 solenoids front of valve body and manifold pressure sensor .
no result ....................

about the clearance i used Zpak installation sheet and i am sure from the clearance its correct

my car HP???????
we dont have dyno in my area but i think its around 700+ also i can go up by increasing the boost to 900+hp



thanks

mrvedit

At 700+ HP you are exceeding the capability of most 4L60E.
Take a look at the parts in e.g. the FLT Level 7 or the Performabuilt Black edition, which just had a detailed writeup in the current edition of Super Chevy magazine.
Both use the Sonnax SmartTech input drum, which is the only way the 3/4 clutch can handle that power level. Billet input and output shafts are also highly recommended.
At 900HP you need a 4L80E plain and simple.

Patro46

Just went through this very issue. Lazy shift into 3rd. 1st and 2nd hit hard and fast. Once i had about 1000 miles on the engine and transmission, I hit her pretty hard. When she hit 3rd, she hit hard then the rpm's shot up and she was slipping. I pulled the transmission and sure enough, my new Z-Pack was cooked. I might add when I bought the transmission, I gave 75 bucks. Guy said it was a fresh rebuild, and when he hit it hard (his was a nitrous car) the same thing happened to him. Coincidence? I doubt it. Once there, we confirmed a defective 2-3 shift solenoid and a lazy pressure solenoid, which makes perfect sense. Seems it was a pressure issue due to the cooked 3 gear clutches the first time around. Same thing happened the 2nd time around and was finally traced down to the pressure solenoid.