I just ordered a Torque drive package for my 4L60E. Here's what they say about it.

700R4 / 4L60E Extreme Duty Torque Drive Package. You get a hardened input shaft and drum assembly plus a hardened reaction shell and bearing. Every time you think there's nothing else that can be done to a 700R4, here it comes. These parts are made to with-stand way over 600 foot pounds of torque. Fits late 1987 up.

Drum: Starting with select cores, the input shaft / drum assembly is disassembled and visually inspected. Then super heated until fully expanded and then X-rayed for internal cracks. Heating the drum collapses any carbon pockets thus ultimately strengthening the cast and stabilizes it. This process is followed by a flux test to determine if any external fractures are present. If all checks well a specially machined alloy support ring is then married to the drum.

Shaft: The shaft is cold and hot chemically forge treated to a military standard Rockwell 38 hardness. Then stress relieved which gives the shaft double the strength of its stock counterpart. The parts are reassembled and spun balanced at 9500 RPM. This step insures that this assembled unit will spin true with absolutely no harmonic vibrations to disturb engaging parts (stock factory units were never balanced to this degree). The input shaft / drum assembly comes with a specially machined over-run piston and high temperature seal.

Heavy Duty Shell / Bearing Assembly: A new reaction shell is provided with a reinforced hub that is approximately twice the thickness of an OEM reaction shell. The reaction shell is hardened then spun balanced at 9500 RPM. We replace the OEM plastic thrust washer with a roller thrust bearing to reduce heat. A specially machined and hardened rear planetary inner race is included to complete the assembly.

 

I got mine from Chuck Johnson at Finish Line Transmissions.

 

This is what FLP

says bought level 5
4L65E includes the above Level 4 parts with the addition of:

GM 5 pinion planet assemblies front and rear
GM reaction shaft with bearing
FLP's extreme duty sun shell with bearing which is stronger than GM's 4L65E shell
Cryogenic treated input shaft, output shaft, & reaction shaft


That is different than billet,cryogenic means they freeze it.

 

Soooooooo maybe I should still get an aftermarket Hardened Shaft of some sort? "Survey says..."!!!

 

I got it for mine i Have heard of too many people toasting these parts atleast in the 60e mine is upgraded to a 65e now. I got the above mentioned torque drive kit on my truck but Im also making nowhere near the horsepower that you are. I would do it if I were you. Just my .02

BTW mine was the shot peened one I beleive didnt want to spend the $400 for the billet

 

I hear you... I will definitely get it if that's what is being recommended. It seems the 4L65 already has an "upgraded one" but it may not be enough.

 

What you have is the OE hardend shaft,thats good,the next step would be the reinforment kit.A sleave goes over a hubbed area,it keeps things tight so the shaft splines cant turn and break the aluminum drum.Next is the TQ drive kit,its a finished input drum inspected and balanced and has there own special treated shaft along with the reinforcement sleave (once the sleave is on it needs a special apply piston which is part of the kit).Now I am guessing but FLP sends out OE shafts and has them cyroed or frozen treated.It will be news to me if FLP takes billet steal and carves out there own or has it done.I have an email to them now.there stage 5 trans says they cyro theres.

 

I got an email from FLP,and if I undertood correctly they just recently made availible a billet output shaft only,for 4x4 or AWD units only and that single piece sells for $800.So the input is either shot peened or hardend or cryogentic or a combo.

 

Wow, $800!! I wish someone knew what was really required for any given amount of power. If, for example, "billet is required for 600hp" then everyone that had 600hp would know to use it. Of course it's not that easy so we all have to go with whoever we want to listen to and feel comfortable with. I'm definitely going with an aftermarket hardened shaft ($350). I'll just have to assume that's going to be strong enough!

Thanks for the good info Gonzo!

 

I just got an email from FLP.He said the 4x4 output shaft is $500 not $800.He also said they are currently looking for someone capable of making them a input shaft out of billet.