Poor Shift Feeling
Test drove it and none of the shifts felt as firm and positive as they did before.
The changes made were:
New 3/4 clutch setup
2 5/8 wide band
77701-076 sonnax
Revmax 3600
Transmission was pulled due to a 3/4 issue.
Who ever put it together before had way way too much clearance, even before clutch wear.
Used a 8 disk 7 kolene steel setup
8 Friction with GPZ105
.215 Apply
8x .066 Friction GPZ105
7x .078 Kolene steel (TranStar part #74120AK)
.157 Backing
.092 Snap ring (stock)
was .032 wet after air check
Any help would be appreciated.

As Revmax said, a higher stall will soften the shifts.
Do you have a 0.500 Boost valve in it?
This will firm up the shifts and reduce the chance of any clutches slipping.
The 2-3 shift will never feel as firm as the 1-2 shift anyway.
See this thread:
https://ls1tech.com/forums/automatic...-question.html
The suggested Sonnax boost valve can be installed after only dropping the pan and filter.
So whatever boost valve that is.
I think it needs some tuning for the converter. It shifts, but feels like a weak stock transmission.
Under more throttle it feels like a cvt
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Now just mush.
Does just a tune seem realistic?
I suspect you are losing pressure somewhere. Start by checking the line pressure with a gauge. Get a gauge ($45 on ebay) or have a trans shop check it for you.
Getting about 45 psi at idle in park.
At 3,000 rpm getting about 150 psi.
This is using my snap on scan tool. I can hook up a mechanical gauge later.
What is the procedure to do this?
The driver side of the case has a "port" normally plugged. an 11mm or 7/16" wrench removes the plug. Then I think is is a 3/16" pipe thread.
Search ebay for a "Transmission pressure gauge" - you only need the single 300psi gauge. I have the "ATD-5550" one for $50.
(Due to my experiments and mixing of parts, your idle_in_park pressure might be a bit lower, but should still be over 90.)
BTW - Where are you in Michigan? I am in Ann Arbor.
I assume you are mostly referring to the 1-2 shift. A 0.093 drill for the 1-2 feed hole should be plenty. If this shift feels soft, possibilities are low line pressure (which you are checking soon), a leak in the 1-2 accumulator such as a cracked piston or torn gasket, a leak in the servo, or excessive play in the band.
You mentioned installing the Sonnax 77701-076 Check valve. The instructions specify a .130 drill for the 2-3 apply hole for performance apps. (1/8" is .125 which is close enough) The orifice also needs to be drilled according to which servo you have. All this will only affect the 2-3 shift, which will always feel pretty soft with a 3800 staff. It should sound like a fast shift though.
I will wait for the result of your line pressure test.
Took the car to a tuner to see if it was the tune being the issue.
Still felt like crap.
Tuner agreed that it was not normal what so ever.
He sent me to a performance trans guy.
They suggested it could be a converter issue.
Since it is the only new part that is a component in all gear.
I had no issues before with 1-2 shift.
Has anyone had any similar issues?
They have my transmission out and are inspecting it.
Once they're done I will try the converter again. If it's the same mush, I will put my 2500 stall back in. If it fixes it that would rule the rest of the transmission out.










