93 K1500 5.7-bone stock Recently had a reputable builder put together a basic 4L60E. I'm a 20+ year tech and simply didnt have the time to do the research nor the time to learn by mistake. Well I probably should have just done this thing myself because it's been a complete cluster. I'm going to try to skip all the drama though and get to the point.

The second rebuild is flaring in the 2-3 shift under moderate load to wot roughly 200-500rpm. I've got a oversized 2-4 servo pin coming due to excessive play. I'm of course concerned it could be friction material clearance related but at this point I'm tired of dealing with this situation and this builder so hopefully with the forums help I can put this thing behind me. If it turns out the clutches are burnt I'll deal with the builder.

I've done a significant amount of searching online about the 2-3 flare. I know there's a lot of size recommendations online but most are for modded trans with high stalls etc. I'm hoping with the correct feed and release hole sizes I can correct this issue if the OS pin doesn't help.

The current sizes are below and the build specs. Any help would be much appreciated.
1-2 .062
2-3 .081
3-4 .096
BR .096
LR .096

Parts List:
*TransTec Overhaul Kit – Rubber Seals, Metal Clad Seals, Sealing Rings, Paper GasketsMaster Rebuild Kit with all clutches and steels, name brand clutches such as Borg Warner or Raybestos
*Filtran Brand Transmission Filter
"Borg Warner High Energy 2-4 Band
"Late model 3/4 Clutch One Piece Apply Plate
*Teflon Pump Bushing
"Teflon Extension Housing Bushing
*Bronze Front and Rear Stator Bushings
"Bronze Case BushingThrust Washers
*Pump VanesPump GuideHardened Pump Rings
"Hardened Spline Sun Shell
*New Solenoids
*Aluminum 1-2 Accumulator Piston
*Aluminum 3-4 Accumulator Piston
*Bonded Pistons
Updated Sonnax TCC Regulator Valve
Updated Reverse Input Capsule
Updated TransGo Zinc Coated Separator Plate
Factory stall 1400-1600

 

I would start with installing the New Servo Pin with a Clearance of approximately 0.060" End-Play.

There is a very good chance that will solve your issue if the current Clearance is rather excessive.



Going to a Corvette Ratio Servo would also be advisable (and often helpful in this situation as well).

 

Thanks for the reply. I'm hoping the pin corrects the flare too. I installed the Vette servo and a new pin with one shim/spacer already. It still has about .125+ movement depending on how hard I leverage on the cover.

I've came across the .060 specs during my research. If i had the proper gm gauge I'd get as close to 060 as possible. But being the gauge needle can fluctuate 010-020 depending on how hard I push I was going to shoot for 075. Any thoughts/input?

Any suggestions on the feed holes. I would like to get this thing shifting firmer through all shifts but I want to address the flare first. I would image though the 1-2 062 could be opened up if I have to go back in to address the 2-3 holes.

Any input on setting the servo play or separator plate specs is appreciated.

 

Here are the TransGo HD-2-C Separator plate recommendations.

 

My only concerns due to ignorance are with the non-pwm vs with and feed holes sizes for hd2 shift kit vs without. Meaning would I still use those sizes even though I don't have the hd2 shift kit and does the non-pwm 4L60e make any difference with sizing? I don't imagine the non-pwm would but wasn't sure about the shift kit.

 

This is what I like for shift holes on a relatively stock unit but with some shift feel:

1-2: .063"
2-3: .100"
3-4: .093"
3-2: .100"
Band Release: .082"
Forward: .086"
Low/Reverse: .082"

I wouldn't go much more than .072" on the 1-2, but YMMV. I run vette servo. grind the pin to get .060" servo travel. GM tool wont be much help. most of us use a dial indicator, will be more tricky insitu, but doable usually. remove all the orings when checking, you will most likely need a new cover oring. I also block the 4th accumulator, this helps 4th out a lot.

 

Feed hole sizes would not change with PWM or non PWM

 

Thanks for the response. I've been working with nick transmissions to help with the flare. I've opened up the 1-2 and 2-3 and waiting on a boost valve and oversized servo pin.

While waiting on the parts I opened up the 2-3 to 093 from 081. The BR is 096. The 096 is how the separator plate came new. It unfortunately still has the flare. Can't really say how it effected shifting after the flare bc I let out of it once it starts. Was thinking about opening up the 2-3 to 100 as you stated. I would prefer the BR not be so large in the first place.

As far as the 2-4 servo pin goes i used a dial gauge. There's just some give depending on how much force I apply to the cover.

Any input is welcome and appreciated.

 

use an old steel check ball and place the separator plate on some flat concrete or 1/2" steel. you can then peen the hole smaller. i usually work both sides so you dont dent the separator plate.

not sure what others do, but I only open the BR hole to what you have when I block the 3-2 shift valves. or if the 3rd feed is considerably bigger.