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Chevy says the 4L75E-R was designed specifically to handle the torque output from the automaker’s new ZZ632 Big Block crate engine, which is factory rated at 1,000 horsepower and 876 pound-feet of torque
Other highlights of the 4L75E-R include a strong six-pinion input carrier and sun gear
Stupid decision!
What is that thing going to cost?
I do not follow anything from GM past the Gen-4 SBC and ZF based 6L Transmission Family...
I do eventually read-up on some modern Products through a Corporate News Letter (Twice a Month).
Sometimes something catches my eye... as the 10L Transmission has.
I have not yet heard of this Transmission yet.
However with all the Aftermarket Parts thrown at the 4L75E...
I should not be too surprised that GM is attempting something like this.
I hope GM finally got things ironed-out Hydraulically.
Hard Parts alone are NOT going to do it.
Some definite Hydraulic changes are going to have to happen for those Numbers...
especially Lube and Cooling!
Its hard to believe the puny input shaft splines can take that kind of torque. At either end. Especially with a good converter
The Input-Shaft will handle that much Power with a 300M Shaft.
Even the Early-4L60E/ Late-THM700-R4 Shaft will do, when made of 300M.
The smallest of the bunch is the Early-THM700-R4/ THM200-4R Shaft... also fine made of 300M.
Its hard to believe the puny input shaft splines can take that kind of torque. At either end. Especially with a good converter
4l60e input shaft is a 1" shaft
th400 input shaft is a 1" shaft
th400 1" input in a good material will handle near 2000 hp (sometimes much more in the right combo of weight/power adder/tire/surafce/etc)
So...the input shaft here isn't my biggest worry
Something to double check ,, if a Terminator X is part of the equation the 4L7** series have some challenges, I think most have been worked out but its a heads up thing..
Stupid decision!
What is that thing going to cost?
I do not follow anything from GM past the Gen-4 SBC and ZF based 6L Transmission Family...
I do eventually read-up on some modern Products through a Corporate News Letter (Twice a Month).
Sometimes something catches my eye... as the 10L Transmission has.
I have not yet heard of this Transmission yet.
However with all the Aftermarket Parts thrown at the 4L75E...
I should not be too surprised that GM is attempting something like this.
I hope GM finally got things ironed-out Hydraulically.
Hard Parts alone are NOT going to do it.
Some definite Hydraulic changes are going to have to happen for those Numbers...
especially Lube and Cooling!
What would you suggest they do? It's probably all Sonnax parts, what hydraulic mods would you suggest, AND what hydraulic mods do you think they did or didn't do? Thanks vortec.
Looks like the Sonnax 6-pinion is 2.84. Perhaps Sonnax if producing a 3.06 6-pinion just for General Motors??
My bad... 2.48 would be super close ratio of the '60's... or TH400 I think.
Why didn't they make it closer to 3.06 from the start? They must really think the 3.06 is too wide and just a tire fryer...
I'm not an engineer like some on here; I don't know what's involved to get a certain ratio, the # of pinions may factor in, you don't really see many even #s, at least I haven't... closest was 2.75 I think... wasn't that TH200/200-4R? And 3.50 Ford 9" rearend...3.55 Chevy 12-bolt....I can't recall any whole #s.
Last edited by matermark; Jan 17, 2022 at 10:10 PM.
There is probably a limit to the size of the ring gear without re-tooling the case as well as the thickness of that ring.
I bet it takes an act of god to change some of those dimension at GM ? <vorteciroc?>
I've been looking at this transmission for a while and occasionally do a search to see if it's been released for sale yet (it hasn't) but I ran across this almost dead thread.
Has anybody heard any updates since January about this transmission?
Other forum discussions bring up the very steep 1st gear ratio (3.08). It can be cured with the Sonnax six pinon 2.48 1st/1.55 2nd front gearset but it's added expense and work-and I'd assume doing the change would void any warranty.
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Chevrolet Performance 4L75E-R 
