Got the 2008 4L60E pulled, Tore down, Inspected, Cleaned up & going back together.......
These "rebuilds" are a JOKE, Been that way forever but I'm still amazed at the level of hackery that goes on! Adding Insult to Injury is I saw the invoice from 2018 & they charged $3,400, I'm at $3,900 fixing their screw-up's along with replacing parts that should've never been put back in this unit!
What the previous builder did....
*New Frictions & Band....He did use good Borg Warner's.
*New Case & Pump Bushings......Two bushings total in a unit that has 12 bushings?
*Sanded all the Steels effectively ruining them. Wasn't a good job either.....Only 1/2 of most of them were sanded.
*Sanded on the Reverse Input Drum where the 2-4 Band applies......Thus ruining it.
*New Seals.
*Trans-Go SK-4L60E shift kit (I use this kit as well...Most of it anyway)
*Blocked the 3rd Clutch Release check ball capsule, Bad idea!!
*Blocked the 4th Accumulator, I do this as well when running a stock 4th Apply Servo, But he reinstalled the Accumulator Piston cutting off all Lube to the Lo/Reverse Clutch which oils in 4th gear on a stock unit.
*Rebuilt Converter that I found out today is a piece of junk....Had my Converter guy cut it open because I didn't find the smoking gun for the No Lock-up/Falling out of Lock-up HOT condition.
Back in 2018......That's $200 worth of parts.
What I'm doing....
*New Borg Warner Frictions & Band.
*7 3-4 Frictions vs 6 on a stock unit. Set at .025" clearance.
*Good used Lo/Reverse, Reverse Input, & Overrun Steels.
*New Forward & 3-4 Clutch Steels.
*New OE Reverse Input Drum....New flat surface for the 2-4 Band!
*New Bonded pistons.
*Bushings 100% replaced.
*Borg Warner Input Sprag.
*Corvette 2nd Servo Piston.
*Sonnax long Servo Pin, Trimmed to achieve .040" Band Clearance.
*Sonnax/KOYO bearing kit.
*New OE 4L65E Sun Shell.
*New OE Reaction Shaft....Original heavily worn.
*Good used Output Hub....Original heavily worn.
*Reusing the TransGo SK shift kit.
*New Pump Kit with TransGo unbreakable Hi-Rev Ring Kit.
*Sonnax .490" Boost Valve & 10% over Pressure Regulator Spring.
*New OE Separator Plate.....Modified 3rd Clutch feed & release orifices, Enlarged 4th feed, Will leave 2nd Clutch feed stock.
*New OE 2nd Accumulator Housing (loaded).
*New OE internal harness.
*New OE ISS Sensor.
*New OE TCC PWM Solenoid.
*Rebuilt Converter with a new Sonnax friction lining.
Approximately $900 in parts alone (My cost)
First picture....He went to town on the steels with what looks like Green Corps 3M sanding disc's....But only half to 3/4 of the steel. This practice goes way back & IS flat WRONG as it damages the Friction Surfaces. Replace Steels in Dynamic Clutch packs & you can reuse Steels in Static Clutch packs assuming no hot spots are present. 4L60E's only have 2 Dynamic Frictions.....The 3-4 Clutch & the 2-4 Band.
Second picture....Good used Lo/Reverse Steels after cleaning them up in the parts washer with a Scotchbrite pad.
Third picture.....Worn Reaction Shaft Splines where the 3-4 Hub rides....This allows the Hub to wobbles around causing 3-4 Clutch Drive Tang wear.
4th picture.....New Reaction Shaft for comparison.
5th & 6th picture.....Forward Clutch stacking up.
7th & 8th picture....3-4 Clutch stacking up.
9th picture....New Reverse Input Drum laced onto the Input Drum.