When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Slide locked for maximum volume
7 vane rotor
properly sized separator plate orifices
7-cs springs in the 3/4
I'd run stiff springs in the reverse drum with an added bleed hole
extra bushing support in a couple key areas...mainly both sun gears, case, and stator tube
Kill the 4th accum and use the additional spray lube to help the rear
a little extra 3/4 clearance won't hurt as long as you properly time the 2-3 shift
Slide locked for maximum volume
7 vane rotor
properly sized separator plate orifices
7-cs springs in the 3/4 I'd run stiff springs in the reverse drum with an added bleed hole - What springs do you use for stiffer ones? extra bushing support in a couple key areas...mainly both sun gears, case, and stator tube - can you elaborate on this? Are you talking installing wider bushings? If so, didnt know there was room for wider in the upper sun gear? At least dont remember there was? As well as case?
Kill the 4th accum and use the additional spray lube to help the rear
a little extra 3/4 clearance won't hurt as long as you properly time the 2-3 shift
There are different Reverse Input Piston Return-Springs that can be used...
I have used many different Springs that were sold for Power-Glide, THM200-4R, and THM350 Trans-Brakes.
The Rear Sun-Gear Bushing ends-up being one of the most-important Bushings as a "Floating Gear-Train"/ Center-Supprtless Design Transmission.
On every unit, I would Install Two Factory Bushings on-top of one another...
Instead of the Sonnax Wide Bushing (that can be problematic with fitment).
Two OEM Bushings creates a slightly wider surface area over the Sonnax Bushing.
Be mindful of the Lube-Holes!
The Case Bushing width fits the Rear Ring-Gear VERY well... I am happy with it.
The case could possibly accommodate a wider Bushing... if desired.
Sonnax offers Wider Bushings for the Stator-Support that work well.
Something that I usually do away-with is the Front Sun-Gear being retained by the Tabs of the Sprag-Assembly.
I almost always enlarge the Output-Shaft Lube-Passages for the Sprag-Assembly...
and ensure that the Front Sun-Gear Bushing placement is ideal for proper lubrication.
The Lube Oil between the Output-Shaft and the Reaction-Shaft can also be increased.
More Lube between the Output-Shaft and the Reaction-Shaft...
as well as the Reaction-Shaft, and the Rear Sun-Gear.
More or less... this should suffice for Higher RPM Builds.
Centrifugal apply of the Reverse-Input Clutch, and Pump Volume are the two more important things to deal with.
I was hoping that Maroon Monster would still add to this further
...as I believe he is the most experienced builder on the forum, of high-performance 4L60E Units.
I always find his contributions to be of value.
Even when he is just breaking-*****/ havin' fun!
I feel like he has not been receiving as much credit as he deserves recently...
So if you guys see him Posting, it is always nice to receive a: "Thank You", in this Business.
Thankyou for all the replies , the trans will be purely used at the strip, engine is making peak power @ 8400rpm and shifting @ 8700rpm. Still tossing up whether to stick with the 4l60e or convert to th400.
it's a 355 cube holden engine , 685hp , 493 ftlb naturally aspirated.
If it’s just strip go turbo 400. Then you don’t have to worry how many passes it will stay a live. Also the amount of money to keep that trans a live at that rpm is not worth it imo
I am assuming you are referring to the Input-Drum Check-Ball Capsule that is under the 3-4 Clutch Piston.
I have seen some of the Aftermarket replacement Check-Ball Capsules be too tall and interfere.
What is your recommendation here?
Only after sealing-up the many, many leaks in the 3-4 Clutch and 3rd Accumulator Circuits:
I personally add a 0.060" bleed under the 3-4 Clutch Piston (in addition to the Check-Ball Capsule) for Higher RPM Units...
as well as a bleed under the Reverse-Input Piston (I see more issues here with unwanted centrifugal-apply).
The TH400 would be more problematic at those higher Engine Rpms...
Unless going to lighter aftermarket Forward, and Direct Drums.
If any of you are looking to go with a THM400, and have a high-Reving Engine...
There is an amazing Aftermarket Forward-Drum/ Direct-Drum, that has been around for over 20-years now.
Look up John Kilgore Racing/ THM400 Transmissions.
He is an amazing Builder! ...and has designed his own Drums, that I am referring to.
(John Kilgore Super-Lite THM400)
Otherwise, more traditional Drums are also produced in Alloys of Aluminum, and some in Titanium.
If any of you are looking to go with a THM400, and have a high-Reving Engine...
There is an amazing Aftermarket Forward-Drum/ Direct-Drum, that has been around for over 20-years now.
Look up John Kilgore Racing/ THM400 Transmissions.
He is an amazing Builder! ...and has designed his own Drums, that I am referring to.
(John Kilgore Super-Lite THM400)
Otherwise, more traditional Drums are also produced in Alloys of Aluminum, and some in Titanium.
It's a modified TH180 drum, Kilgore has always been an innovator in the transmission field. I remember running into John at the Long Beach performance swap meet held here in Cali when he introduced this set up.
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.
7 Most Reliable High-Performance Engines GM Has Ever Built
Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
