4L60E - Lots of questions!

I will go with the sonnax pinless 4th then and use the sonnax 4th gear servo and drill the 3-4 hole to .093 in the plate along with the other suggestions you provided. Thanks again Chris!
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More dumb questions....

1. Are all the 4th gear sections of the OEM servos pretty much the same, or do they also have variance in them like the 2nd gear section? Meaning if I get a 8642079 or 8673039 Corvette servo, is the 4th gear section the same as what you would find in a Trailblazer SS, Standard V8/truck V6 piston, Small V6/I4 piston 4L60E... or is there variance on the 4th gear section as well? I know that the 2nd gear servo has pistons with numbers ending in 093, 95-1, 159, 553, and 554 which all have different diameters (both corvette 2nd gear servos being 1.75 dia), just wasn't sure if the 4th Gear section is different also?

2. I see there's like 10 different codes for the 1-2 OEM accumulator sleeve. A, AX, B, BX, YZ, C, CX, D, DX, R which all have different large and small diameters. Is there a reference which states which vehicle year and models/trim that have 4L60's came with which code, and can they be determined by just looking at the code stamped on the transmission itself?

"A" accumulator sleeve in 700R4's
"B" accumulator sleeve in 700R4's & early 4L60E's
"C" & "CX" accumulator sleeve in 4L60E's in the late 1990's
"D" & "DX" accumulator sleeve in 4L60E's late 1990's through 2005?

3. I'm seeing quite an assortment of 1-2 and 3-4 OEM 4L60E accumulator springs. Orange outer, Orange inner, no color outer, pink inner, purple outer, red outer, green outer, no color inner, yellow outer, white outer, blue outer... has anyone come up with a reference for spring rates on all these and/or what vehicles they come out of? GM part numbers for all of them are listed in the wit catalog. Some of them I found:

1-2 accumulator orange cone shape 1.485" outside diameter X 1.288" tall X .160" coil thickness. 35371A 8663385
1-2 Accumulator Spring red 1.485" outside diameter X 1.656" tall X .114" coil thickness. 35371B 8634703
1-2/3-4 Accumulator spring, purple 1.401" outside diameter X 1.308" tall X .131" coil thickness. 35371C 8634163
1-2/3-4 Accumulator spring, white 1.485" outside diameter X 1.342" tall X .138" coil thickness. 35371D 8654183
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All stock 700R4/4L60E 4th servos are the same.

There are a ton of Accumulator Bushing/Sleeve/Valve codes if you want to span 700R4 & 4L60E. From my experience.....
All trucks with V8 or Large V6 (4.3L) got D/DX code bushings.
All cars with factory Vette Servos got C/CX code bushings. (Vette, V8 F-Body, GTO).
Many 60° 4L60E's got B/BX code bushings.....Used behind I4, I5 S10 & Colorado, 3800/3400 powered F-bodies.
All other codes came in 700R4 or Early 4L60E's

Largest to Smallest.....I'm going to use the single letter codes for simplicity.....
I know there's a YZ & R code listed.....But I don't remember seeing one in the wild.

Don't know of any good references for Accumulator valves or Housing springs, Though year specific GM reference manuals usually listed the 2nd & 4th Accumulator Spring Color Codes.....Someone would have to compile all those manuals & test spring rates of all the springs.

I like using Green Outer Spring 24219942 or Purple Outer Spring 24209794 along with Green Inner Spring 24220145 or Yellow Inner Spring 24220146. Depends on availability not so much on preference.