4L60E - Lots of questions!

[primetime]

I'm attempting to increase my knowledge on the 4L60E. I know nothing about it, would like to know what it takes to make one of these live at 750hp at say race weight of 3600 lbs, spinning to 7200 rpm. No heavy N2O usage. 2000 core. Street/strip manners. I have a ton of questions, and parts that I've read that are used in 4L60E builds. Apologies that this is so long. There are numerous questions embedded in this list.

Advice requested on if any of these are typical wear items that should be replaced, or are these all able to be reused in most cases?
Input Sprag assembly, keep stock but install a new BorgWarner 29 Element Sprag 4L60E - 29236AM
3/4 clutch apply ring
Reverse input spring retainer (leave stock springs)
Low/Reverse spring retainer (leave stock springs)
3/4 clutch spring retainer (replace springs using transgo 7-CS kit)
Coast clutch spring retainer (replace springs using transgo 7-CS kit)
Sun Gear input
Forward planet
Ring Gear
Rear Sun gear
Low roller clutch inner race
CS install a new BorgWarner Lo/Reverse Roller Clutch 4L60E - 28571AM
Rear Planet (Reaction Pinion Carrier)
Rear Ring Gear
Rear hub
Low/Reverse Piston
Front Pump assembly with some mods.
Case & Bellhousing

Pressure plates/apply plates

Note that diagram below is different that wit diagram, reference this link: https://www.wittrans.com/New_link_parts.php?type=4L60E

Which get replaced with new, which typically don’t:
Reverse Input Pressure Plate (150 on wit diagram)
Forward apply plate (149 on wit)
3-4 apply plate (141 on wit)
3-4 pressure plate (140 on wit)
Forward pressure plate (148 on wit)
Low/Reverse Clutch spacer plate (155 on wit)

Wave plates – replace all with new?
Forward wave plate (129 on wit)
Rev Input Clutch wave/dish plate what to use? (131 on wit)
Low/Reverse clutch wave (135 on wit)

General
Overhaull kit – Transtec 74002EF
Steel plate kit - Transtar 74139EA (doesn’t include the 3-4 steels) good or are AC Delco or better steels needed?
Friction kit – Borg Warner B74119B
Thrust washer kit - SAP K77907
Piston kit – High performance blue – A74960EHPK
Stator Shaft Bearing - 8642066
Bearing under sprag - 8642162
Rear planetary bearing - 8642215
Reaction carrier bearing to reaction shaft (2 of these, one used in another location) - 24217327
Reaction Shaft Bearing (not needed, only 04 and up) 24217328
Durabond bushing kit TK-23HP and Sonnax 77010-01 bushing – all that’s needed for bushings?
Sonnax shims for endplay?

Case
Removed factory 3rd accumulator, install Superior K0136 directional switch valve
Block 4th accumulator with 5/16 set screw, remove piston and spring
Remove #6 checkball (overrun)
Remove low/reverse encapsulated check ball
1-2 Piston Accumulator assembly - 24219937, aluminum 2nd accumulator piston with hardened pin, blue TransGo spring, piston, then orange TransGo spring

2-4 Servo
Sonnax 77911-03K 2nd servo
Sonnax 77767K 4th servo
Sonnax 77787-02K servo pin kit
TransGo blue 2nd cushion spring inside large white factory cushion spring
Modify factory steel 2nd apply cover for quicker exhaust
Cut fluid relieve notches in the cushion spring retainer
Raybestos Pro-Series wide carbon/kevlar 2-4 Band - RPS77765
Set pin clearance to .075" for a Pro-Series Band

VALVE BODY - This is what was recommended, but unsure of which shift kit or combination of shift kits to buy?
Vac test valve body, address replacement items as needed
4209354 valve body
3-2 control valve blocked inboard (best way to do this?)
3-2 downshift valve blocked inboard by using a TransGo 4L60E-HD2 spacer spring
Central valve bodies .001" oversized AFL valve - 4L60E-AFL
TransGo white AFL spring inside factory AFL spring (which kit is this in?)
TransGo yellow low overrun spring (which kit is this in?)
TransGo white 1-2 accumulator spring (which kit is this in?)
TransGo 1-2 shift valve and spacer - SK 4L60E
Sonnax 77754-41 HD 2-3 shift valve
Sonnax 77754-35K forward & reverse abuse valve kits
Sonnax 77964-08K o-ringed end plugs
Sonnax 77754-03K TCC regulator & isolator kit
Sonnax Pinless Forward Accumulator Kit 77987-01K
#2 check ball removed, hole plugged
TransGo seperator plate w/ steel reinforcement corner plate 46-PLT-96
GM OE plastic 6L80E Checkballs

Orifices drilled to:

Band release - .104"
Rev input - .104"
3-4 clutch and 3-4 clutch signal - .110"
1-2 shift - .096"
2-3 shift - .140"
3-4 shift - .110"
Low/reverse - .093
Forward clutch - .086"
AFL factory size

Electronics replacement – OEM for shift solenoids and Rostra for all else?
Pressure Switch Manifold - 24219581
Harness - OTS-77995E
Shift Solenoids -24230298
Pressure control solenoid -24220158
3/2 downshift solenoid - 24212327
TCC PWM solenoid - 24227792

Pump:
2420661 pump
Re-seat pressure relief ball
Wide bronze inner and outer stator bushings
10 vane rotor
13 vane slide w/ new pin
Slide/rotor at .002" minimum and .003" maximum clearance to pump body
Delco Rotor & Slide part numbers & nominal thicknesses information needed!
TransGo hardened retaining rings - 700 PKH
TransGo high RPM priming spring - 700 PKH
TransGo .500 boost valve - 4L60E-BOOST
TransGo orange bumper and orange main regulator springs (which kit are these in?)
Sonnax 77805E-K TCC o-ringed apply valve kit

Lower unit of Case:
Factory lower 4 pinion carrier
Borg warner HD low/reverse roller clutch (already mentioned) 28571AM
Borg Warner low/reverse clutches
Raybestos "turbulator" steels (needed, or use Transtar steels?)
Sonnax 74678L-HD billet output shaft 2WD

Upper unit of Case
GM factory 4 pinion upper carrier
Sonnax 77010-01 wide sun gear bushing (already mentioned)
Sonnax 77749-02K smart shell
Sonnax 74602-01K HD reaction shaft kit

Input Drum
4L79.com drum kit with Sonnax 77733-11S billet input shaft pressed in (non reluctor 300MM)
4L79 custom 3-4 apply plate .180" (comes in 4L79 kit)
8 Raybestos custom wide 3-4 clutches .062" (comes in 4L79 kit)
8 4L79 custom wide 3-4 steels .072" (comes in 4L79 kit)
Set the 3-4 clutches at .025" minimum and .040" maximum
5 4L79 custom load release springs (comes in 4L79 kit)
Sonnax 77733-51K reinforcement sleeve kit with billet overrun piston
Hi-per blue molded 3-4 and forward piston
TransGo 7CS hi-rev forward and 3-4 springs
Borg Warner overrun clutches
AC Delco overrun steels (needed, or use Transtar steels?)
Borg Warner forward clutches
Raybestos forward steels (needed or use factory steels?)
Sonnax 74574-HD sprag clutch hub
Borg Warner 29 element dual cage forward sprag (already mentioned) 29236AM

Reverse input drum:
Reuses stock reverse input drum
Borg Warner clutches
Raybestos "turbulator " steels (needed, or use Transtar steels?)
Alto lower wave plate (replaces beveled plate) part number needed.
Replace outer bushing to except roller bearing to replace plastic thrust washer

Suggestions that I’ve come across

Leave the reverse/input piston alone "no restrictor" in the aluminum piston.
Block the checkball capsule completely and add a .035" hole at the bottom on the input drum just below the outside seal area on the 3-4 apply piston.
Tig tack welded the low reverse drum snap ring in place
Block 4th accum by driving a check ball into the feed hole in the case. Peen the edges for insurance against popping out
1-2 accumulator needs to stay active
Target more than 220 psi line pressure on the pump

Additional questions:
1. Any lubrication mods, additional machine work, rollerizing areas to be mindful of?
2. How does one prep new inner and outer races as I’m told they need to be prepped properly if using new? (or just keep old races?)
3. Any items circled in red on diagram below typically replaced? Tried to circle the parts that I think can be re-used, and are not "replace no matter what" type of parts. This obviously assumes planetary gears are in good working order with less than .025" play. I also need advice needed on the common wear items and what to look out for on the hard parts.
4. Delco Rotor & Slide part numbers & nominal thicknesses information needed!
5. Prefered front and total endplay specs for rollerized and non rollerized?
6. For rollerizing the 4L60E, what areas are machined, and what bearings are used in the pockets?
7. As the 4L79 drum from Mason includes the clutches and steels, what is the best part numbers to use for sorcing the other steels and frictions such that you can ensure that clearances are correct without having to machine any pressure plates.
8. Installation of the shaft into the drum requires correct supporting of the drum, but not something to worry about as the whole assembly would be purchased from 4L79.
9. I see that pressure places are available in varying thickness, idea would be to measure stock pressure plate thickness and replace with new whatever is closest in thickness.
10. What is the recommended clutch pack clearance for each clutch pack for this particular application?
11. Is the sonnax sun shell or the beast sun shell better?

 

[Brian123]

Turbo400 with a Gear vendors Overdrive

 

[paulo57509]

When I lost 3rd gear in the Safari, I purchased a heavy-duty kit for the Safari from Dana at Pro-Built Automatics. It's not cheap (was a lot cheaper in 2014) but it takes the guess work out of mixing and matching parts to get something that works together.

Pro-Built

Welcome to Pro Built Automatics

probuiltautomatics.com

Eight years and 40k miles without any issues on the rebuild (100% Dexron VI). I used all the kit parts except for the new stator; I couldn't find anyone local that would R&R the part from my pump.

I picked Pro-Built because of his positive presence on thirdgen.org. Tech support is a phone call away; it may take 24-36 hours for a response - he's a one-man operation. I picked them because they're West Coast (no time zone differences, etc.).

 

[clinebarger]

I'll have to get my Pump Rotor notes for the gear thicknesses....Be patient.

You do not need a Sonnax Input Shaft, It's splined into a aluminum Input Drum & the drum will always be the weak point no matter what you do (Heat treating, Reinforcement sleeve.
Though I do recommend a Sonnax Output Shaft or have yours Cryo treated....A stock one at this power level can spiral fracture & take out the Carriers!!

Replace the Reverse Input Drum with a Delco one, Wide Bands need a new Drum!!

Sonnax Smart Shell is the only shell I use on performance builds. Beast shells are trash with a capital T!

The Durabond bushing kit comes with a wide sun gear bushing, No need to buy the Sonnax one.

Replace the Reaction Shaft (602) with a rollerized version.....GM discontinued the early style compatible with a 2000 Input Carrier, The Sonnax one works with both early & late Input Carriers.

4L60E wave plates can generally be reused, Use "Turbulator" steels in the Reverse Input & Lo/Reverse.

There are only three 3-4 Apply Plate I would consider using......
Stock 4L60E.....P/N 8685044
Stock 4L65E.....P/N 24217451 (Marked HD)
The Apply Plate out of Sonnax P/N 74140-01K
*Listed thickest to thinnest....If you need actual thicknesses of the 2 stock plates....Let me know.
**EDIT.....I see the 4L79 drum comes with a apply plate**

If you're going to manually shift this unit.....Remove the wave from the Lo/Reverse Clutch, You will need the modify a couple old steels to take up the space from removing the wave.
TH350 Lo/Reverse Frictions are .099" And 700R4/4L60E Lo/Reverse Frictions are .087".....The two interchange if you need some fine adjustment.
Shoot for @ .090" clearance with this clutch.

Rarely do you need to adjust the Forward, Overrun, Or Reverse Input Clearance.

There is no front & rear unit endplay for this unit.....Total endplay only...... .005"-.012" is fine, With new Torrington's & good components, Having to adjust endplay isn't usually needed.

Anywhere the Pinion Gears run needs to be looked at closely after cleaning for wear, All inner & outer splines for wear.

No need to mod the reverse input piston with cup plugs, GM corrected the issue long ago.




VALVE BODY - This is what was recommended, but unsure of which shift kit or combination of shift kits to buy?
Vac test valve body, address replacement items as needed
4209354 valve body
3-2 control valve blocked inboard (best way to do this?) Grind a 5/16" bolt down to fit
3-2 downshift valve blocked inboard by using a TransGo 4L60E-HD2 spacer spring
Central valve bodies .001" oversized AFL valve - 4L60E-AFL
TransGo white AFL spring inside factory AFL spring (which kit is this in?) Both the SK & HD2 kits
TransGo yellow low overrun spring (which kit is this in?) SK kit only
TransGo white 1-2 accumulator spring (which kit is this in?) SK & HD2
TransGo 1-2 shift valve and spacer - SK 4L60E HD2 only, Not needed if tuned to hold Manual Lo via the PCM
Sonnax 77754-41 HD 2-3 shift valve
Sonnax 77754-35K forward & reverse abuse valve kits
Sonnax 77964-08K o-ringed end plugs
Sonnax 77754-03K TCC regulator & isolator kit
Sonnax Pinless Forward Accumulator Kit 77987-01K
#2 check ball removed, hole plugged
TransGo seperator plate w/ steel reinforcement corner plate 46-PLT-96
GM OE plastic 6L80E Checkballs

 

[mattd]

Chris I commend you for spilling all your secrets.

 

[supton]

All of that is over my head—so apologies if I missed it. Was the stock 3.06:1 first gear being kept? I see it is street/strip but 7,200 rpm and aiming for 750hp. I’m not sure the big 1-2 shift is great.

Dumb question: can this be manually shifted, and used like a ‘glide at the track, and normally on the street?

 

[primetime]

Chris, thanks again for taking the time to get me squared away! I just got a hard copy of the hydramatic technicians guide to study up on the lube circuits! These are getting harder and harder to find in hard copy form.

 

[clinebarger]

A Sonnax 2.84/1.55 Input Carrier is $800, I'm running one in a 4L65E in my Camaro, I really like the tighter ratios. The pinions has to be reduced in diameter quite a bit forcing them to a custom 6 Pinion design.

4L60E & their derivatives either need a different 1-2 Shift Valve (Shift Kit) OR tune the PCM to no longer force a 1-2 upshift electrically.

The Wave/Cushion Plate needs removed from the Lo/Reverse Clutch to allow for a cleaner 1-2 shift out of Manual Lo. In Manual Lo.....The Lo/Reverse Clutch is on to provide engine braking, Then when shifted into 2nd.....The Lo/Reverse Clutch needs to come off BEFORE the 2/4 Band comes on for 2nd gear, The wave plate will cause the Lo/Reverse to release a little too slow causing a bind in the unit which burns frictions.

There is an alternative of not having the Lo/Reverse come on in manual lo which requires milling & plugging of some passages in the Valve Body, But you lose the extra support that the Lo/Reverse Clutch gives the Lo/Reverse Roller Clutch.

 

[primetime]

All of that is over my head—so apologies if I missed it. Was the stock 3.06:1 first gear being kept? I see it is street/strip but 7,200 rpm and aiming for 750hp. I’m not sure the big 1-2 shift is great.

Dumb question: can this be manually shifted, and used like a ‘glide at the track, and normally on the street?

Haven't gotten that far yet into the gear ratios, but I'm assuming it can be wired to manually shift (or to rule out electrical issues) similar to the 4L80E.

 

[clinebarger]

Primetime.....If the pump body/cover/rotor/slide are in decent shape, Take it all apart, Clean each component, Install the Slide & Rotor in the Pump Body.

Place four strips of Plastigage evenly spaced on the Slide & Rotor faces, 8 total, Torque the pump halves together.....Let in sit 24 hours, Then measure the the plastic strips.
I'd like to know what clearance you have now & it will make picking a new Slide & Rotor a lot easier!

Do Not install the O-Ring or Support Ring in the Slide when measuring clearance via Plastigage!

 

[clinebarger]

I prefer to use a good outside micrometer to measure the slide & rotor, I don't find digital calipers to be accurate enough for this.

 

[primetime]

Primetime.....If the pump body/cover/rotor/slide are in decent shape, Take it all apart, Clean each component, Install the Slide & Rotor in the Pump Body.

Place four strips of Plastigage evenly spaced on the Slide & Rotor faces, 8 total, Torque the pump halves together.....Let in sit 24 hours, Then measure the the plastic strips.
I'd like to know what clearance you have now & it will make picking a new Slide & Rotor a lot easier!

Do Not install the O-Ring or Support Ring in the Slide when measuring clearance via Plastigage!

Thanks again Chris!

 

[dfarr67]

750hp ??tq I think this exercise is a waste of time- far better choices of trans out there. 4/6L80E, Allison?

 

[primetime]

750hp ??tq I think this exercise is a waste of time- far better choices of trans out there. 4/6L80E, Allison?

4L60E's can live at that power level if built right. I have a 4L80E that will see 1200 rwhp already built with the much needed help from Chris in a different car.

 

[primetime]

I prefer to use a good outside micrometer to measure the slide & rotor, I don't find digital calipers to be accurate enough for this.

I have Mitutoyo digital calipers and micrometer. Will get a non digital as advised.

Chris, do you know if the overrun spring in the VB of a 4L60E is prone to breaking? The one that Transgo recommends replacing with a yellow spring found in step 6 here: https://res.cloudinary.com/transgo/wbiss/rk/4L60EHD2.pdf
If not, what is the purpose of replacing? From what I've read many guys don't buy the Transgo HD2 kit and address the issues a different way. Where would one source the replacement spring instead if stock is really an issue?

Also for high RPM applications, I've read that a common go to approach is to use the orange and blue springs from the Transgo kit on either side of an aluminum piston in the 1-2 accumulator, with no shims. The theory is that the 2 springs will limit piston travel and limit volume and firm the shift because rpm will be climbing rapidly through the range that the 1-2 shift needs to happen. If skimping on the HD2 kit, is there an alternate source for other springs with similar spring rates or a different way to address this while keeping the 1/2 accumulator active?

Just seems like rather than a transgo HD2 kit, one is better off buying these separately and saving $$:
-The High RPM (3-4/FWD) Clutch Spring Kit - 7-CS - $30
- The boost vale and spring - 4L60E-BOOST - $21.79 (or the sonnax option)

Then for dealing with TCC valve/bore wear, just block it with a longer spring so that it's ON/OFF.
No need for the white spring inside the other spring in the AFL, as I read a stock 3-2 downshift spring can be used there to net around a 6 PSI increase?

 

[clinebarger]

I have no issues using stock 2nd Accumulator Housing Springs, A White 24 oz. TG Accumulator Valve Spring.....Then adjust 1-2 firmness with the 2nd Feed Orifice, .086" is usually more than enough with a Sonnax Superhold Servo Piston. Then if you want to calm it down a little, Take the Accumulator Valve Spring completely out.

Or you can run a smaller feed orifice, Say .082", Run a heavier Accumulator Valve Spring, Say a Blue 56 oz.
If you want a little bit more firmness....Step-up to a Yellow 72 oz. Spring.

I like using the TG SK kit because it comes with a assortment of Accumulator Valve Springs & the Pin to make Accumulator Valve Spring changes possible without dropping the Valve body.
Has the 2 extra Servo Cushion Springs needed.
I like running the white spring inside AFL spring.
If I need to block valves.....I machine spacers.

I haven't seen a Low Valve(Overrun) Spring break on late model 4L60E's. But it comes with the SK kit so I use it.

 

[primetime]

Thanks Chris, makes perfect sense! So in theory, it would also be possible to achieve more firmness by experimenting further with a different 1-2 orifice hole and leaving the 1-2 Accumulator Setup mostly stock as follows:

*Updated accumulator housing 24227711
*Transgo 4L6-2ACM 1995-03 Type 2 aluminum piston
*Both both springs in the housing stock (GM 24209794 and 08685656)
*Accumulator Valve spring stock
*Accumulator Valve sleeve stock
*Low overrun Valve spring stock

But since the TG SK kit allows accumulator valve spring changes much easier without dropping the VB, it's better to address it that way and just purchase the SK kit. Got it!

One thing that was throwing me off on the kit offerings was that the HD2 kit contains the orange and blue springs for use under the 1-2 accumulator housing along with spacers and then it has 88oz and 24oz spring offerings for accumulator valve springs, while the SK kit uses 3 springs (orange white and red for a type 2 aluminum piston setup) along with 5 different springs for the accumulator valve springs and it has 1st type and 3rd type 1-2 accumulator options as well. Different ways to achieve the desired effect based on my very limited understanding of the hydraulics, but surprised they didn't just include the parts from the SK kit mentioned above in the more expensive HD2 kit to offer more adjustment?

https://res.cloudinary.com/transgo/wbiss/rk/4L60EHD2.pdf

https://res.cloudinary.com/transgo/wbiss/sk/SK4L60E.pdf

 

[clinebarger]

The SK 2nd Accumulator Springs are meant to soften the 1-2 shift as much as possible.....I don't use those springs mostly because they break far too often & tears up the Accumulator Housing.

I'm with you on they should've included a full range of Accumulator Valve Springs in the HD2 kit along with a quick change pin.

Of coarse neither of these kit take in account for a 2nd Servo larger than a Vette Servo., That's you need to be prepared to do your own calibration.

Transgo 4L6-2ACM isn't technically compatible with Housing 24227711, TransGo 4L65-2ACM is the correct replacement. 4L6-2AM will bottom out before fully loading the Inner spring causing a firmer 1-2 shift, But if that's is want once the Band is seated in.......It's just another Tool in the Toolbox!

That's also another thing to know when building 4L60E's......The 1-2 shift firmness will change over the first 200-500 miles, if its a little soft at first....Wait 'til the Band gets seated before making any changes.

 

[primetime]

I read that it's best to use the "updated 1-2 housing", but it didn't even cross my mind that it's the 4L65E! I incorrectly assumed that the 24227711 was a later 4L60E part and didn't cross reference the part. Thanks for the correction! So maybe as an initial attempt, I'll try the following in terms of accumulators, case, VB, servo, and the pump. What are your thoughts on blocking of the 3-4 accumulator?

1-2 Accumulator Setup
* Updated accumulator housing 24227711
* TG 4L65-2ACM 1995-03 Type 2 aluminum piston
* Both both springs in the housing stock 05-06 Vette springs
* White 24 oz. TG Accumulator Valve Spring
* 2nd Feed Orifice, .086"

3-4 Accumulator Setup
*Block the 4th accumulator feed hole with a brass 1/16 - 27 NPT fine thread set screw with Loctite
*Won't install anything here, remove piston and spring
*Will leave the 4th accumulator check ball out as well

Forward Accumulator Setup
*Replace plastic piston with aluminum piston 4L6-FWD, keeping everything else the same.

Servo
*Sonnax 2nd and Sonnax 4th with Sonnax dual PTFE seal pin
*Use GM# 8642539 outer cushion spring & GM# 8681195 inner cushion spring.
*Cut fluid relief notches in the cushion spring retainer
*Set pin travel to .060” which should work well with an Alto 057961C carbonite wide band and Sonnax servo selection above

Case
*Remove #7 low/reverse encapsulated check ball and assembly.
*Install the Superior K0136 directional switch valve
*Delete #1 check ball, the one right by the accumulator housing
*Delete #6 check ball to allow more oil to more quickly apply the over-run clutches

Valve Body
*Remove each valve/spring and clean
*Vacuum test the valve body and address leaks as needed
*TG SK kit, using only the modifications mentioned
*1-2 accumulator sleeve and spring (see above, TG White 24 oz to start)
*Low overrun spring - use TG yellow
*Sonnax HD 2-3 valve 77754-41 to apply the overrun in 2nd and 3rd
*Tune the PCM to no longer force a 1-2 upshift electrically
*Block the 3-2 Down Shift (#389) and 3-2 control (#391) valve inboard with ground down 5/16" bolts
*Convert TCC to ON/OFF with spacer
*TG Separator plate, 46-PLT-96 is the correct one for a 2000 core
*Central valve bodies .001" oversized AFL valve - 4L60E-AFL (hopefully don't have to ream and vac test is good)
*White spring in the TG SK Kit placed it inside the AFL spring to increase pressure roughly 6 PSI
*Sonnax 77754-35K reverse abuse kit (only purchase 1 of these as 3-2 is blocked so not needed for that bore)
*4L60E‐ABUSE‐BP is an option instead of 77754-35K
*Sonnax 77964-08K o-ringed end plugs
*Sonnax Torlon Check Balls 10000-08, seat correctly in new VB by peening the holes
*Drill the orifices to the following based on the selection of other parts mentioned:

Band release - .104"
Rev input - .104"
3-4 clutch and 3-4 clutch signal - .110"
1-2 shift - .086"
2-3 shift - .155"
3-4 shift - .125"
3-2 shift to 0.120”
Low/reverse - .093
Forward clutch - .086"
AFL leave factory size

*Replace all electronics, but no need to replace the 3-2 solenoid or TCC solenoid based on mods above.
*Install a 0-300 psi. pressure gauge and note the readings at WOT at 4,000 rpm and higher. Aim for pressure to be 235 - 245 psi. If lower adjust with EPC solenoid. If higher, remove 3-2 actuator spring used in the AFL bore and possibly adjust EPC solenoid if needed.

Pump
*Clean pump screen filter, pressure relief ball and spring, converter clutch valve, pressure regulator, and filter seal all need the parts removed in the respective bores and cleaned.
*Vacuum test the various pump circuits, address as needed
*TG drop in pressure regulator valve 4L60E-PR in the pump, along with a 4L60E-BOOST boost valve kit
*Use unbreakable pump rings and spring, TG 700 PKH For use above 5400 RPM
*13 vane slide, new 10 vane rotor (match thickness), new vanes, .002" minimum and .003" maximum clearance

 

[clinebarger]

I usually leave the 4th Accumulator active when using a Sonnax 4th Servo Piston, With a .125" Feed & the Accumulator blocked.....The 3-4 shift will be on the harsh side.
When using a stock 4th Servo Piston.....I block the 4th Accumulator 100% with a .250" check ball driven into the case.

Using a Sonnax Pinless Accumulator piston in the 4th Accumulator will reduce the range of accumulation while still taking the initial bite out of the 3-4 shift when using a Sonnax 4th Servo.

Use the TransGo TCC Regulator Valve to covert to on/off.

The SK Servo Cushion Springs work well, Blue & Black springs added inside the stock spring, No need for the flat coiled spring.....It's to restore integrity to the stock-used cushion spring, But I've never found it necessary.

Both 4L60E & 4L65E were updated to the same 1-2 Accumulator Housing, Not sure why TransGo put 4L65 in the part number other than to differentiate between the Small Pin Piston with legs & the Small Pin Piston without legs.
But....Yes I would run a piston without legs with LS2 Vette Accumulator Springs.

Drill the AFL holes to .055", Reduces the chance of debris clogging them, But DO NOT drill them to .093" like TransGo advises.