Geartrain noise in 4L60E second gear causing "knock" retard

[Fast355]

I've built 700's for 502, supercharged 383's (600 rwhp) and nitrous cars... have had a couple issues, but they're still running....
the planets are actually bigger than 4L80E, but the hard parts actuating things are different, and the 80E does have an extra planet in front for overdrive, it for sure is heavier duty. Will be good to know how stuff works out...

I tore the case lugs off the side of the case in one. Broke the "beast" sun shell in another and broke an aftermarket input drum in another. Each time it looked like a grenade had gone off inside. The weakest point gave out and when it failed, took the whole unit out. I had one that cracked in the bellhousing area as well on a stock 2.8 S-truck.

I picked up the ATSG manual on the 4L80E and plan to build it myself. I will let you know how it works out. The beefier OD is one of the main things I am after, since I plan to swap either 4.10 or 4.30 gears into it and will be towing in OD.

[greggbruceauto]

I tore the case lugs off the side of the case in one. Broke the "beast" sun shell in another and broke an aftermarket input drum in another. Each time it looked like a grenade had gone off inside. The weakest point gave out and when it failed, took the whole unit out. I had one that cracked in the bellhousing area as well on a stock 2.8 S-truck.

I picked up the ATSG manual on the 4L80E and plan to build it myself. I will let you know how it works out. The beefier OD is one of the main things I am after, since I plan to swap either 4.10 or 4.30 gears into it and will be towing in OD.

very cool -- not too difficult to do, the 60's and 80's are easier than the other brands (engineered WAAAAYYY better)...and practice makes you better....
I figured out on a couple of them the reverse boost valve "upgrade" made too much pressure and broke things.
also the pressure regulator spring "upgrade" in some of the shift kits do the same thing. I lowered the pressure (stock spring) a little and hit the magic button, things stayed together better.....

[RobertISaar]

I had one that cracked in the bellhousing area as well on a stock 2.8 S-truck.

you know something is awesomely engineered when a ~125HP/~155TQ engine in a ~2700 lb vehicle can kill it.

i've had bad experiences with 700R4s in the past.... not so sure i would want to deal with another or something that was derived from it.

[Fast355]

Gotta love it...Knock retard entirely in 2nd gear but absolutely none at the 2-3 shift. I ran it 107 mph in 3rd gear at 4,500 rpm with the converter force locking at 85 mph and had less than 2* of knock retard and was pushing 200+*F coolant temps. That was as fast as the brick would roll into the wind up a slight grade.

[EagleMark]

And you can't hear a noise of feel a vibration in second gear?

[Fast355]

And you can't hear a noise of feel a vibration in second gear?

It does have a slight whine/vibration that is most noticeable in 2nd gear.

[Fast355]

As a few may know, I nuked first gear in the 60E on wednesday. Not having built my 4L80E core yet, I picked up a 97K mile used 4L80E from a 2002 Express G2500 with a 4.3 for $625.00 with a 6 month warranty.

[pmkls1]

Dang, $625 seems high even with the warranty, but they are a little tough to find.

After thinking about my post way back about just building a good 4L60E I realized that I hadn't taken into account what you drive and what you use it for. Having something that big and heavy and towing with it does make swapping in a 4L80E the better choice. That brings me to a good point, though. Most people don't understand the way that a transmission's rating is calculated. It isn't just horsepower that is taken into account. Actually, horsepower isn't taken into account, torque is. But torque is just part of the equation, gross vehicle weight is the other part. Lets say you have a 500 horsepower engine for example. If it's in a 2500lb car it still isn't going to place the same strain on the drivetrain as if that same engine were in a 5000lb van. Then add the towing weight on top of that and you have more strain with the same engine. That's how GM rates their transmissions and that is why you can have a 180hp 4.3 in a van and they put a 4L80E behind it, but you can have a 400hp 6.0 in a vette with a 4L65E behind it.

My point is, the 4L60 variants are more than capable and adequate for performance use and are often underestimated. But, it your particular case Fast355, you were right that a 4L80E is much better suited for your application. Good luck and I hope that the swap goes smoothly.