Harsh 1/2 shift --- 4L65e

[slowfive0]

I pulled the trans to have the converter tightened up and since I was there I had the trans ckd out. Found that there had been some slippage in the forward clutch and the band so I had my trans rebuilt with billet input and output shafts, billet 2nd and 4th gear servos, etc. Previously, it had a corvette servo (nice crisp shift), but this time we went with the billlet 2nd gear servo along with all of the other mods. The trans shifts great, but the 1/2 shift is really firm at moderate to heavy acceleration. The builders intent wasn't to create a firm or harsh shift, but he was trying to increase capacity/holding force.

The trans is in an AWD Silverado SS that currently runs 12.20's. I will be dropping those times down into the 11's and I'm afraid with the firm shifts I have now, it will break stuff.

I would like to soften up the shift by one of the two methods:

1. Reduce the values in the 1/2 shift pressure table
2. Go back to the vette servo

I would prefer #1 but I'm afraid of reducing the pressure and potentially damaging the band.....Maybe a normal practice though hence my question....

Thoughts?

[Dusty05]

Are your pressures at stock level right now?
I agree with you on not wanting to cut the pressure in half, I'd just go back to the vette servo.
I can't wait until I can control the slushbox in my truck

[slowfive0]

Pressures are elevated over stock. Around 225-230psi. I agree that the vette servo is looking to be the best option.

Right now, if I understand how this table is working corrrectly, I'm cutting my line pressure down xx% at the time of the 1/2 shift. If I understand that correctly, that is not only cutting my pressure for the 1/2 shift, but pressure in the trans overall. In other words pressure to the forward clutch which I can't think is good.

There is another table besides the "Shift Pressure" table that can be used to make adjustments to the 1/2 shift. It's called "Shift Pressure Modifier Upshift" table.

I would like to know what that table does specifically different than the "Shift Pressure" table?????? Thanks for the feedback.

Are your pressures at stock level right now?
I agree with you on not wanting to cut the pressure in half, I'd just go back to the vette servo.
I can't wait until I can control the slushbox in my truck

[gman4dx266]

I think that the new servo is whats cranking your pressure up.

If other gears are okay, I would do a trial and error test on taking about "10" off from 200ft lbs and lower from your NORMAL shift table. If you're running in to it bottoming out @ zero in your pressure table and still being too much, then your only options are:

1) Replace that solenoid with a vette
or
2) [if thats not an option] take the left half of your force motor table and add 150 or 200 to it, fade them together to get a ramp, then go back and firm up the 2>3 and 3>4 shifts.

Personally, I wouldnt think that servo would do that to you to that extent but anything is possible.

[zippy performance]

If you'd like, send it to me and I'll see if I can fix it for you.

[slowfive0]

Thanks Zippy. E-mail sent your way.

If you'd like, send it to me and I'll see if I can fix it for you.