How goes it guys, looking for some recommendations on feed hole sizes to a rebuild im in the middle of.....

Vehicle & specs
- 1998 Pontiac Trans Am
- 4l60e with a N/A 9.5" 4400 stall
- N/A H/C/I
- 7200 shift points
- past tranny line pressue 235 psi

Transmission mods
- 3-4 clutch clearance. 035"
- 2-4 band clearance. 055"
- 3-2 downshift & control valve blocked inboard
- 4th accumulator blocked
- Sonnax 2nd & 4th servos
- Sonnax 2-3 shift valve
- Sonnax Performance pack

I did not drill yet but here is where I was leaning...
- Band release .095" (thinking this is going to be to small with the sonnax 2nd servo)
- 2nd apply .095"
- 3rd .140"
- 4th .140"

Thanks much and I can answer any questions needed if info was left out

 

2nd feed will depend on your accumulator setup for the 1-2

the 4th feed is fine. You'll be hard pressed to ever make that shift TOO firm
I usually go .110 on 4th but .140 should be fine

 

1-2 accumulator is the one from sonnax performance pack

 

Fairly aggressive accumulator setup imo
I'd probably start with .078
no need for the 1-2 to be overly firm

 

clinebarger said long ago not to use the sonnax wave spring in the 1-2....so I dont....he also said he does not like the ..legs...on the piston....so I ground them down....I do not like the stiffeness of the sonnax springs so I use diff GM springs.....I keep the 1-2 feed hole on the small side....I love my 1-2 shift !!!!

my .02

 

ok, thanks, I do remember reading about tossing the wavy.

Don't remember the grinding of the legs part. Do you happen to know why this was done?

 

I also found this thread by bbond105 and we have very similar setups across the board and will probably follow similar recommendations as posted by MaroonMonsterLS1 in post #2.

https://ls1tech.com/forums/automatic...ld-advice.html

 

I think Cline had a issue with the size of the piston and the legs interfering with total travel in the bore.....with the legs ground you get about a xtra 1/8 inch of travel

I think the stiff inner spring limits the travel....does the piston actually compress that inner spring? if so...how much ?

using the sonnax springs the length of the outer puts the piston at the top of the bore...i see why the need for the wave spring...to keep the piston off the plate

using the GM springs that I do...inner and outer.... and the springs are not as stiff as the sonnax...the piston is lower in the bore

i had the trans go SK and always hated the 1-2 shift....i asked n asked about curing that crappy shift ....no one had a answer...this was my experimentation and fix