Another 4L60E build with questions

[jamyers63]

1969 Chevrolet C10 pickup with a mostly stock 350 (Holley Sniper efi and GM HEI ignition, otherwise a stock 250hp engine. It has a 3.73 open rear end, and a 700R4 that slips when shifting from 2nd-3rd under moderate load.

Currently the truck is my son's college daily driver, but he's going to want to rebuild and upgrade the engine in a couple years, so we decided to build a moderately-stout 4L60E with a new stock Converter (for now) that will be able to handle future engine upgrades (not more than maybe 400-425hp, if he wants to go faster he needs a different vehicle)

Picked up a 96 4L60E from a '97 C1500 with 105K miles, was told it worked fine when pulled. We pulled the pan and found evidence of water / dirt ingress (likely via missing dipstick tube hole. We then tore it completely down, and found that while there had been water in the pan, the clutches and other internal parts (except the Reverse Drum which had rust and so was replaced) were fine and it looked like the transmission had recently been rebuilt - the frictions, sprag, gears, thrust bearings, etc all showed little to no wear. We are now in the middle of rebuilding it with these parts, using info from "clinebarger" online, the ATSG Manual, and the Sonnax / TransGo Shift Kit Instructions.

Got a couple questions, of course... @clinebarger if you could take a look at this I'd appreciate you input.

1. Separator Plate drilled orifice sizes? I got those from clinebarger's posts here, but now I'm thinking some of them are too big - comments?

2. We're using the Sonnax TCC isolator - regulator valve because it specifically claims to limit the converter apply pressure. But the TransGo TCC Isolator-Conv Regulator Valve claims to be better in a used Valve Body - but I can't find anything on it's limiting the converter apply pressure... So which is the better option?

3. I'm planning on blocking the 3-2 downshift valve inwards, unless in this application it's best to leave as is?

4. The total end play is within the ATSG specs, but I'm thinking it could be tighter - is it worth tightening it up?

5. Anything else I should address?

Group	Brand	Parts	Specs	Source
Accumulator Mod	TransGo	1-2 Accumulator Spring from kit, based on 093 piston and DX bushing	White	TransGo
Accumulators Parts	GM	1-2 Accumulator Housing and plastic piston, part #24226359 (supercedes GM24227711)		Amazon
Accumulators Parts	GM	1-2 Outer Cushion Spring, part #24209794		Summit
Accumulators Parts	GM	3-4 Accumulator Spring		Core
Accumulators Parts	Sonnax	3rd Accumlator Checkball Capsule		Amazon
Accumulators Parts	Sonnax	3-4 Accumulator Pinless Piston Kit		HP-4L60E-01
Accumulators Parts	Sonnax	Forward Accumulator Piston with OE Spring		HP-4L60E-01
Accumulators Parts	Sonnax	Forward Accumulator Spring		HP-4L60E-01
Clutches / Internal Parts	Alto	Kolene (nitrided) Clutch Steels, all, kit #		Ebay
Clutches / Internal Parts	Borg Warner	HE Frictions, all		Ebay
Clutches / Internal Parts	Durabond	Seamless PTFE-coated Bushings		Summit
Clutches / Internal Parts	GM	Reverse Input Drum / Housing, part# 24245624		Amazon
Clutches / Internal Parts	GM	3-4 Clutch Apply and Backing Plates		Core
Clutches / Internal Parts	GM	3-4 Clutch booster springs		Core
Clutches / Internal Parts	Sonnax	Sonnax Wider, PTFE Rear Stator Support Bushing, Part No. 77002BT-01		Durabond Kit
Clutches / Internal Parts	Sonnax	Sonnax SmartShell Heavy Duty Reaction Shell Kit, Part No. 77749-02K		Summit
Clutches / Internal Parts	WIT	Hi-perf Blue Apply Pistons, all		Amazon
Clutches / Internal Parts		Low-Reverse Clutch Height	1.220	ATSG
Clutches / Internal Parts		Forward Clutch Clearance	0.045	ATSG
Clutches / Internal Parts		3-4 Clutch Clearance	0.065	ATSG
Clutches / Internal Parts		Reverse Input Clutch Clearance	0.045	ATSG
Clutches / Internals		Total End Play before and after rebuild	0.030	ATSG
Electrical Parts:		Wiring Harness and TCC Solenoid		Amazon
Electrical Parts:		5-piece New Solenoid Kit		Amazon
Electrical Parts:		Pressure and Temp Switches / Sensor		Amazon
Gaskets and Seals:	Transtec	Gasket / Seal Kit (gotta love the lip seal installer tool!)		Amazon
Pump:	GM	Pump Vanes		Core
Pump:	Sonnax	Boost Valve with O-Ring .490"		HP-4L60E-01
Pump:	Sonnax	Elevated Pressure Regulator Spring		HP-4L60E-01
Pump:	TransGo	Hardened Pump Rings and Hi-Rev Spring, part# 700RK		Summit
Pump:		Rotor and Slide Clearance	0.001	clinebarger
Separator Plate Mods		Drilled Hole A (3-2 shift) = .101	0.101	Clinebarger
Separator Plate Mods		Drilled Hole B (2nd Clutch) = .076	0.076	Clinebarger
Separator Plate Mods		Drilled Hole C (3rd Clutch) = .139	0.139	Clinebarger
Separator Plate Mods		Drilled Hole D (4th Clutch) = .093	0.093	Clinebarger
Separator Plate Mods		Drilled Hole E (AFL Balance oil) = .052	0.052	Clinebarger
Separator Plate Mods		Plugged PWM Hole according to Sonnax TCC instructions		HP-4L60E-01
Separator Plate Parts	TransGo	Separator Plate, part #46-PLT-96		Summit
Servos / Band Mods	TransGo	added Servo Cushion Springs	Blue and Black
Servos / Band Mods	TransGo	4 notches ground into Servo Steel Cover
Servos / Band Parts	GM	2nd Apply Piston, 093 'Corvette'		Amazon
Servos / Band Parts	GM	Servo Cushion Spring	OEM	Core
Servos / Band Parts	Raybestos	Pro-Series wide band, Part #RPS77765		Amazon
Servos / Band Parts	Sonnax	SuperHold 4th apply piston, part of kit# 77767K		Amazon
Servos / Band Parts	Sonnax	Servo Release Check Valve (helps with 2-3 shifts and band release)		HP-4L60E-01
Servos / Band Parts	Sonnax	Extra-long Band Apply Pin, part# 77787-02K	.076 clearance	Summit
Skift Kits:	Sonnax	Performance Pack, Part No. HP-4L60E-01		Amazon
Skift Kits:	TransGo	SK4L60E series L (1993-2002)		Summit
Valve Body Mod		"Special Pin" for Accumulator Bushing, allowing easier changes		TransGo
Valve Body Mod		Installed yellow spring on Low Overrun Valve	Yellow	TransGo
Valve Body Parts:	Sonnax	Sonnax Heavy Duty 2-3 Shift Valve Part, No. 77754-41		Amazon
Valve Body Parts:	Sonnax	TCC Pressure Limiter Valve & Spring (eliminates PWM/EC3 function)		HP-4L60E-01
Valve Body Parts:	Sonnax	Pinless Forward Accumulator Piston		HP-4L60E-01
Valve Body Parts:	Sonnax	Plastic (Delrin?) Checkballs (8)		HP-4L60E-01

 

[clinebarger]

I'm going to use GM Orifice numbers......This is for Both 3-2 Valves active, Vette Servo, 3-4 Clutch Clearance @.025", 2-4 Band Clearance @.040".
Orifice #16 (2nd), .073"
Orifice #12 (Band Release) .086"
Office #13 (3rd Exhaust) .093"
Orifice #28 (3rd) .093"
Orifice #7 (4th) .101" (Edit....., .086" is great with a 4th Superhold Servo & blocked Accumulator)
Orifices #8 & #32 (AFL) .040" to .055"

You don't need a Sonnax Performance Pack, Just buy a Boost Valve & PR Spring separate (LB1 Line Booster Kit). Aluminum TransGo Forward Accumulator Piston is fine....No need for a pinless one (4R6-FWD).
Sonnax also has a pin version (74927-AP)
I've had issues with the Sonnax Servo Release Check Valve.

The TransGo TCC Regulator Valve works great, While it doesn't limit TCC pressure.....I've been using it for over 20 years without a single converter failure associated with TCC Pressure!

A OE/Borg Warner hi energy 2-4 Band is good to 600HP with a Vette 2nd Servo!!!!

Block the 4th Accumulator in the Case with a steel checkball, Omit the 4th Accumulator Piston & Pin......Accumulator oil with now lube the Lo/Reverse Clutch at all times.

DO NOT tighten the Reverse Input Clutch Clearance......045" is way too tight. Using OE friction's will set the clearance just right.
DO NOT tighten the Lo/Reverse Clutch Clearance, Using OE friction's will set the clearance just right.
Same with the Forward & Overrun clutches, Using OE friction's will set the clearance just right 99.5% of the time.

Saw no mention of a Forward Sprag or a Lo/Reverse Roller Clutch?? New Borg Warner for both. GM part# 24237394 is a little stronger than the Borg Warner Forward Sprag.....But they run $200 & not really needed at your power levels.
*Sonnax Heavy Duty 2-3 Shift Valve......Not needed at this level with a good Forward Sprag!

 

[jamyers63]

Thank You!

I should clarify though, we've already assembled the geartrain inside the case and the servos with the parts above - but I'm perfectly willing to dive back in there, lol. The valve body is still on the bench, and I already have the above listed parts on hand.

My philosophy was to build an overkill transmission that would be pretty much bulletproof well beyond the expected future power levels (Son has mentioned swapping a mild Buick 455 that I have sitting in a crate, but that'll be years down the road lol), so that no matter what happens in the future the trans will NOT be the weak link. Was I off base? Will a transmission like I'm envisioning be a harsh beast for daily driving?

To clarify more and ask yet more questions:

"I've had issues with the Sonnax Servo Release Check Valve."

Just curious, what issues? We put in a new GM checkvalve and it tested good, fwiw.

"The TransGo TCC Regulator Valve works great, While it doesn't limit TCC pressure.....I've been using it for over 20 years without a single converter failure associated with TCC Pressure!"

I'll go with the TransGo Iso-Conv valve - possible to use the Sonnax regulator spring with the Transgo valve? (edit, NOPE the transgo valve is longer and has additional lands compared to the Sonnax valve.)

"A OE/Borg Warner hi energy 2-4 Band is good to 600HP with a Vette 2nd Servo!!!!"

We replaced the Reverse Input Clutch Housing, so I picked up the wide band while I was at it, following my overkill philosophy – any downside to the wide band with a Vette 2nd Servo and a Sonnax 4th?

"Block the 4th Accumulator in the Case with a steel checkball, Omit the 4th Accumulator Piston & Pin......Accumulator oil with now lube the Lo/Reverse Clutch at all times."

Given the above, still recommend disabling the 4th Accumulator? (just curious how the lubing works, is it from the Accumulator exhaust?)

"DO NOT tighten the Reverse Input Clutch Clearance......045" is way too tight. Using OE friction's will set the clearance just right.
DO NOT tighten the Lo/Reverse Clutch Clearance, Using OE friction's will set the clearance just right.
Same with the Forward & Overrun clutches, Using OE friction's will set the clearance just right 99.5% of the time."

Those Clutch clearances above are what we measured using the Alto steels and BW frictions (then compared to the ATSG book specs). Looks like I need to revisit them – what are your recommendations on specs and methods to attain them? Do I need to chase down new OEM frictions for everything except the 3-4s?

"Saw no mention of a Forward Sprag or a Lo/Reverse Roller Clutch?? New Borg Warner for both...."

The existing Sprag and Low/Reverse Roller Clutch looked great (no wear marks at all on the races or dogbones / rollers, so we re-used them - but I don't mind swapping in new Borg Warner bits.

To confirm part numbers, Forward Sprag = 29236AM, and L/R Roller Clutch = 28571AM ?

"Sonnax Heavy Duty 2-3 Shift Valve......Not needed at this level with a good Forward Sprag!"

Any downside to using the Sonnax HD 2-3 valve? (I already have it, plus I hate how my 2000 Silverado freewheels in 1st and 2nd, seems like a lot of abuse on that sprag when driving around pastures...)

 

[jamyers63]

Also, given that I'm going back into the case, would I be smart to just replace all the bearings with new? They looked and felt great, but...

 

[clinebarger]

Didn't know you already bought parts......

When using a Pro Band.....Set Band clearance to .065"-.070"

Go ahead & keep the Sonnax 4th Accumulator piston......093" 4th feed will be fine. If you look at the bottom of the 4th Accumulator, You will see a Orifice Cup Plug, This to lube the Lo/Reverse Clutch while in 4th gear. If you were to block 4th feed & install a piston.....The Lo/Reverse will not longer get lube oil.
That's why I omit the piston when blocking the 4th Accumulator as it allows Accumulator Oil to feed the lube circuit.


"Just curious, what issues? We put in a new GM checkvalve and it tested good, fwiw."
***Slight bind-up....Especially on 3-2 downshifts.

"Any downside to using the Sonnax HD 2-3 valve? (I already have it, plus I hate how my 2000 Silverado freewheels in 1st and 2nd, seems like a lot of abuse on that sprag when driving around pastures...)"
***Not when notching the 2nd Servo Cover per TransGo instructions, Helps with the "Clunkiness" associated with having the Overruns on all the time.


"The existing Sprag and Low/Reverse Roller Clutch looked great (no wear marks at all on the races or dogbones / rollers, so we re-used them - but I don't mind swapping in new Borg Warner bits."
***Was the Forward Sprag a Dual Cage design?

"Those Clutch clearances above are what we measured using the Alto steels and BW frictions (then compared to the ATSG book specs). Looks like I need to revisit them – what are your recommendations on specs and methods to attain them? Do I need to chase down new OEM frictions for everything except the 3-4s?"
***Borg Warner is OE, They're a light Red before soaking them. Do the Alto Steels have "Turbulator" holes in them?
How did you measure the Reverse Input Clutch clearance?

 

[jamyers63]

Okay, We'll reset the band clearance, keep the Sonnax 4th Accumulator piston and 093" 4th feed, and leave out the Servo Release Check Valve.

IIRC, the sprag was a single cage, I've ordered BW dual cage one as well as new BW L-R Clutch and will swap them in.

Okay, the frictions were light red, but the Steels do not have any holes in them that I recall. I'll let you know when we get back into there.
I got them from here: https://www.ebay.com/itm/222525235611
Googling up "4L60E Turbulator Steels" I see that they have 4-6 holes/slots in them - if mine don't have them, why not drill/deburr/chamfer them?


We measured the Reverse Input Clutch with a feeler gauge between the Backing Plate and the Snap Ring, making sure the snap ring was at the top of it's groove. Now that I look back at both the ATSG book and the ATRA .pdf 'book', I see that they both have the same procedure EXCEPT that the ATSG book adds in "air-check the Reverse Input Piston to check for leaks after installation" before it says to check the clearance. We assembled those bits a couple weeks ago, I honestly don't remember air-checking the piston - could be that everything wasn't seated properly if I didn't?

Additionally, since I'm going back into the case, I've ordered new bearings and thrust washers what sort of total end play would you like to see with the Sonnax Smart Shell and it's roller bearing?

 

[clinebarger]

They're not holes, They're rounded slots, Non directional on the Reverse Input & Directional on the Lo/Reverse.

These slots allow extra oil to flow through the clutch pack when they're Overrunning & the above 2 clutch packs do ALOT of Overrunning.

.045" clearance & lack of Turbulator Slots will cause the Reverse Input Clutch to run hotter than I'd like.

Yes, Always seat the clutch before measuring clearance.

 

[clinebarger]

When using the Sonnax Smart Shell you got to watch your 6 on Output Shaft Endplay.....

 

[jamyers63]

Aha! Thank you again for the input.

(Age-restricted video, lol)

 

[jamyers63]

Turbulator steels should be here this week and we'll swap them in as well as the sprag, one-way roller clutch and all new thrust bushings and bearings. Will also go with the TransGo TCC Isolator-Conv Regulator Valve, and NOT use the Sonnax Servo release valve.
Will also look at tightening up the band clearance.

* What sort of clutch clearances (all clutch packs) would you like to see here - same as posted above, except a wider Reverse Input?

* If a clutch pack clearance needs to be opened up a little bit, could I take a steel and thin it on a wide sander or surface grinder?

* Are the Separator Plate Hole Sizes I've got above ok?

* Any reason to leave out any checkballs?

* Anything else we should address?

 

[clinebarger]

Yeah I'd like to see at least .050" on the reverse input clutch, .045" is fine on the Forward Clutch, .025" on the 3-4 clutch, .065"-.070" for a wide Pro band.

Machining the Reverse Input Piston is the best way to gain clearance.

Use the Plate Hole sizes I listed in post #2.

You can remove the captured checkball in the case down by the Lo/Reverse Clutch if it's still there, Other then that....Install all of them......1 in the Case & 7 in the Valve Body.

 

[Merek]

Good luck with it, you really can't build a 4L60E enough, it needs all the help it can get. Mine is still doing good in my truck but if something ever happens I'll either have it rebuilt stronger or go with the 4L80E. I guess depending on how it was abused or not they seem to last anywhere from 150k-200k miles give or take.

 

[jamyers63]

Yeah I'd like to see at least .050" on the reverse input clutch, .045" is fine on the Forward Clutch, .025" on the 3-4 clutch, .065"-.070" for a wide Pro band.

Just double-checking, that's .025" on the 3-4 clutch?

 

[clinebarger]

Correct.

 

[jamyers63]

Okay, after going back into the case this weekend (hard to keep focused in the shop when it's 105F and up, whew!)

All new thrust washers and bearings (except the captive bearings inside the planetary gears, but they rotate smoothly and feel like new).

Here's the closest we could get to spec with what we have on hand so far, after air testing / seating all clutches / pistons. And being super OCD about measuring 3 or 4 times, with both feeler gauges and dial indicator.

Speaking of 'specs', I find the variety of specs published to be...interesting. For instance:
Low Rev Clutch: ATSG book says 1.200-1.240", ATRA book maths out to 1.107-1.214, TransTec instruction sheet says 1.15 to 1.18"
Forward Clutch: (ATSG, ATRA, TransTec all say .030-.063)
3-4 Clutch: (ATSG says .060-.085, ATRA and TransTec both say .035-.083)

* Low/Reverse Clutch: 1.185" overall height with wave plate, OEM/BW frictions, new or old/core turbulator steels (we tried both), and OEM selective plate (Note: the core's steels are turbulators and look like new, and measure the same thickness as the new Raybestos turbulator ones. The Kolene non-turbulators measured slightly (a few thou) thicker, fwiw).

* Forward Clutch: .045"

* 3-4 Clutch: .036" w/ 6 frictions and Kolene steels, shooting for clinebarger's .025" Doing some math shows that the next thicker Backing Plate (have a 'C', going to a 'B') would reduce it too much, between .026 and .042. Ideas on how to get to take out .011"?

* Reverse Input Clutch: .050" with turbulator steels

* Servo / Band Apply pin clearance, measured as per Sonnax superhold 4th piston instructions: .070 (good thing we looked at this one, we had the washer/eclip stackup wrong).

End Clearances: Watched the video and followed along as best we could (not having an H-gauge).

* Output Shaft: added a .010" shim to the new bearing behind the SmartShell, got .015" endplay as in video.
* Total Endplay: .011" with a .015" shim on the #69 Selective Washer, measured with a dial indicator on the shaft end, everything assembled and torqued down.
* Did NOT double up the plastic thrust washer behind the pump - don't know of Kenny and never seen that anywhere else...

 

[clinebarger]

* 3-4 Clutch: .036" w/ 6 frictions and Kolene steels, shooting for clinebarger's .025" Doing some math shows that the next thicker Backing Plate (have a 'C', going to a 'B') would reduce it too much, between .026 and .042. Ideas on how to get to take out .011"?

Yet another reason I run 7 friction 3-4 stacks........080" Frictions & .077" Steels to start.....Then you have more options like a .095" Steel in place of a .077" Steel.

Are you running late 4L60E Backing & Apply Plates?

Leveling the Apply Cage (The 5 fingered cage) is easy way to gain small amounts of extra clearance.

Guessing you're running .080" frictions & .106" steels?

 

[jamyers63]

Yup, .080 frictions and .106" steels"... Looks like I'll be pulling the Apply Cage out and taking some off the fingers...

...unless you think it'd be better to get some thinner steels and run one more friction. Speaking of which, all of the kolene steels I see online are .106" - the thinner ones aren't treated (that I can tell). So is more untreated steels better than fewer treated ones? (I don't mind swapping new parts out of this trans, as I've got a 2000 Silverado that's going to need a trans rebuild one of these years and whatever I don't use here might be useful then)

The 3-4 clutch pack... I read lots of stuff about clearances vs. RPM, removing or keeping the 5 sets of release springs, different numbers of frictions, kolene vs. thin vs. thick steels, Sonnax vs. OEM apply / backing plates, etc... What's your approach (or rule of thumb) as to what mods to do at what power levels?

 

[thastinger]

Nobody makes billet input shafts, drums that hold more clutches, center supports with bearings etc for this thing? If I was going to build it, I would only do it once. Your Son isn't going to stop at 450HP, trust me on that.

 

[clinebarger]

Yup, .080 frictions and .106" steels"... Looks like I'll be pulling the Apply Cage out and taking some off the fingers...

...unless you think it'd be better to get some thinner steels and run one more friction. Speaking of which, all of the kolene steels I see online are .106" - the thinner ones aren't treated (that I can tell). So is more untreated steels better than fewer treated ones? (I don't mind swapping new parts out of this trans, as I've got a 2000 Silverado that's going to need a trans rebuild one of these years and whatever I don't use here might be useful then)

The 3-4 clutch pack... I read lots of stuff about clearances vs. RPM, removing or keeping the 5 sets of release springs, different numbers of frictions, kolene vs. thin vs. thick steels, Sonnax vs. OEM apply / backing plates, etc... What's your approach (or rule of thumb) as to what mods to do at what power levels?

7 .080" Frictions & 6 .077" Kolene Steels is my preferred set-up in a stock Input Drum.

Alto makes .076" Kolene Steels (Usually .077" actual) see picture below.

GM part# 24216939 are .095" thick & have a "LINDERED" surface treatment that is very similar to the Kolene Nitrating process.

Always use the 10 Load Release Springs around the OD of the 3-4 Clutch!, I recommended replacing them with new Sonnax Springs (10 in a kit)

OE GM Apply & Backing plates work very well! I keep 2 different thickness Apply plates & 2 different thickness Backing plates in stock.....

GM# 8685044, Apply Plate, .220"
GM# 24217451, Apply Plate, .213"
GM# 24212460, Backing Plate, .193"
GM# 24212459, Backing Plate, .157"

​

 

[clinebarger]

Nobody makes billet input shafts, drums that hold more clutches, center supports with bearings etc for this thing? If I was going to build it, I would only do it once. Your Son isn't going to stop at 450HP, trust me on that.

4L60E's are well supported, But a Sonnax Smart Tech Input Drum is $1000 & comes unloaded, Sonnax Output Shaft is another $700, 2.84 Input Carrier runs $800, Smart Shell $100, Reaction Shaft $200, Reverse Input Drum $100.

Actual rebuild parts.....$1300

Billet Front Stall Converter.....$1000

$5,200 in parts alone.