How do I change 2-3 shift timing only

[Black3]

What controls the part throttle and full throttle timing of the 2-3 upshift on my 87 GN? If I want to increase ONLY the 2-3 shift point by 1-2 hundred rpm or so, is it possible? All my shift points are spaced normal and appropriate except 2-3 which currently happens right after the 1-2 shift. Tightening the TV cable beyond the standard WOT adjustment process we all know how to do only increases all the shift points to too high an RPM and just about knocks the dash onto your lap on part throttle upshifts. For some reason something I did when I installed my trans kit f'd up only the 2-3 upshift and every other tranny function is perfect.

 

[darkhorsebob]

In order to increase only the 2-3 shift you will need to increase the spring tension on the 2-3 shift valve spring. I used to know the formula to calculate how much MPH a certain increase in tension would produce, but I can't remember. A very slight increase in spring tension will raise the shift approximately 5MPH. This will be a trail and error method since you don't have a spring tester to measure the tension for the spring.
The best way to alter the tension is to use thin(shim) washers to shim the spring. Use a machine screw washer with a hole in the center so it will fit on the stem of the shift valve. I would try one washer at a time.
Hope this helps.

 

[chris718]

Measure the tv upshift land on the tv shift valve and I will tell you what valve body to borrow the correct one do do what you want.The shift valve and sleeve can be replaced and later 2/3 or earlier 2/3 can be added to the shift scheduling.Changing spring tension is doable,BUT sometimes if the stack height isnt the same other problems can arise,like leaving the exhaust port under the valve open or slightly open causing slippage.

 

[Black3]

It's something that I did when I installed the trans kit last summer. Before the kit it was not a problem and it's only the 2-3 shift.

 

[chris718]

Did the kit have you change the 2/3 shift tv spring?

 

[Black3]

Did the kit have you change the 2/3 shift tv spring?

I don't remember, when I get home I'll have to check instructions. It's the base CK kit bought through you last summer.

 

[chris718]

We dont give you a spring for the 2/3 shift tv valve.Did you try retorqueing valve body?

 

[Black3]

We dont give you a spring for the 2/3 shift tv valve.Did you try retorqueing valve body?

No, but I will.