C5natie

iTrader: (1)

Well after 5 yrs of running strong, my built 4L65E started to act up after the last track day. It would accelerate just fine up to highway speeds. Once cruising, if I gave it more then 30% throttle, it would would accelerate very slowly and almost feel like it was in neutral. Long story short, I drained the fluid and pulled the pan. Fluid still seemed alright but I found plenty of metal chunks and shavings in the pan. Turned out to be pieces of the input drum lugs. Now I'm going through the trans and building it to be able to handle 1000hp thanks to some goodies that weren't available when I first built it 5yrs ago. The car was putting down 610/575 to the wheels but is currently on the way to making 700rwhp. Thanks to an awesome trans builder, his trade secrets and some quality parts from Sonnax, this thing should be bullet proof. A Circle D triple clutch converter helps get more power to the ground and a 11x11x1.5 B&M cooler with a fan cools the trans.

Some pics of what I found in the pan.










Just a couple of the goodies from Sonnax to help the trans handle the power. Too many parts to list. New sprag, clutches, bands....

Heavy duty 2-3 shift valves apply the overrun clutch in 1st 2nd and 3rd to add durability to the input sprag and forward clutch.


Sonnax Smart Input Drum. Stronger design and bolt on cap keep the drum from becoming distorted with high rpms and torque allowing more pressure to be efficiently applied to the clutches.






Keeping this monster cool. The idea is that at speed the air enters the front (license plate, brake ducts and fog lights have been opened up) and after it hits the intercooler and radiator its deflected up through the trans cooler. The fan assists by pulling air through as well.

mrvedit

Those items are a good start, but I would also add:
* Billet input and especially output shafts
* A new BW forward sprag (should be replaced with each major rebuild)
* The Transgo HD2 shift kit, if not already.
* The wider bushings, Torlon ***** and a few other Sonnax goodies

I used 9x Blue frictions in my Sonnax Input drum.

Comparing the internals of a 4L60E with a 4L80E side-by-side, I would not call even the best built 4L65E bullet-proof. Plus the 4L80E will be cheaper.

NorthTexasConverter

This, absolutely. I wouldn't even accidentally call any 4L6XE transmission bullet proof, however, for Vette owners a 4L80E swap is extremely expensive and not practical for many. It's a much more involved swap than an F-body unfortunately. He's definitely heading in the right direction at least as far as building the trans he has to work with.

C5natie

iTrader: (1)

Those mods and parts have been done or installed as well. 4L80E's have their weaknesses as well and aren't worth swapping over too on a C5.

NorthTexasConverter

4L80Es have no weaknesses that a 4L6XE series have if built properly, aside from slightly more parasitic power loss and added weight. For the cost associated with the swap however, I will agree that it is often not worth it although there are numerous cases where it is. Sounds like you have a pretty stout 4L65E though! For 700rwhp I can't say that I'd feel 100% confident, though if the last one lasted 5 years with ~100rwhp less than you will probably be just fine.

C5natie

iTrader: (1)

What I meant Iis anything can break. The 4L80E is definitely stronger but unless it's a full out serious race car, I can't justify the cost. The only reason I broke lugs on the input drum is because the ecu started failing and commanded too much pressure. Even after 5yrs this thing was solid so I'm pretty confident that it'll handle the 700rwhp for quite a while. ..I hope.