I’m getting my 4l65E rebuilt and the shop guy told me to try and limit the rpm’* of my burnouts to below 5,500. Said that it activates the 3rd and 4th gear clutches without supplying hydraulic fluid. Almost immediately burning them up.
As much as I try to understand auto transmissions they still seem like automotive magic to me. So is there any validity to his statement?

Yes I know burnouts are hard on the car. Yes I expect to break stuff by driving hard. No I will not stop.

I've heard ~5,500 and ~6,000 related to drum speeds, but don't have documentation to back it up. I've never heard of the 3/4 clutch thing.

What kind of car is this in?

It’* in a 2005 GTO. A few basic mods. Just headers, exhaust, and different heads. The transmission is also stock but is a replacement with a few thousand miles on it when it went.
The shop specializes is GM transmissions.
I will say from what he said would happen it fit pretty perfectly. The transmission lost 3rd and barely found 4th. This is just a few days after doing a pretty decent burnout that hit 6k for a few seconds before shifting to 2nd.
And I’ll note that I’ve had to add fluid a time or two. But never found any drips under the car.

Moved from the 2000-2005 forum in the Pontiac Bonneville section to the Pontiac forum.

Wow, well yeah sounds like it is performing appropriately for the conditions in which it finds itself.

Okay but was it what the shop said?
I get it, that kind of stress is stressful on a transmission but for one incident to just melt it seems excessive.
This was less than 10 seconds and probably a total of 2 full seconds at that high of rpm. So if it WAS that and they ARE that fragile then I really need to know.
Not to mention if that is the reason I feel like this could save a lot of transmissions because I haven’t heard this from anyone.

I know that it wasn’t in the best health to begin with. But I feel like this should be a huge piece of information. “Probably” breaking your transmission and “definitely” breaking your transmission are very different.

Was what what the shop said? The reason the old transmission failed?

How many miles were on it?

When was the last service performed?

How has it been treated all its life?

This was on the old transmission, right?

How many miles were on it?

When was the last service performed?

How has it been treated all its life?

They are "that fragile". Now you know. In the real world, nobody does this to their 4L6x transmissions. I have a couple and they are great units. One got to 285,000 miles and still ran fine in a YukonXL when I found a few sparkles in the pan. I had it overhauled and still have it running fine at 330,000 miles right now. They typically fail at high miles and/or under high abuse. There have been millions made across 20+ years of production, and most of them have held up just fine, often under severe conditions for hundreds of thousands of miles in fleet service.

You haven't heard this from anyone because nobody treats their transmission like this. If there is a design flaw here, it is that GM put such a good engine in front of this transmission.

Like any machine, it can be used in a way that can cause it to be broken. Since it is your machine, the manufacturer knows that you have the right to break it if you want. When this occurs, the manufacturer can only protect themselves from having to repair things that people do to the vehicles they produce. To that end, check out the red circled section of your 2005 Pontiac GTO'* warranty guide:



I know your GTO is far out of warranty. This is just explaining the relationship between the design and operation of the vehicle, and where the expectations appear to have been surpassed in your case.

It wasn't?

Maybe this is related to why it failed.

For the conditions that you describe here, "probably" just bridges the gap for how many abuses it will take to break it. If you try something once, then twice, then three times, and it doesn't fail, that doesn't mean it will do that forever without failure, ergo "probably".

If you were to rev your engine to 6,000RPM and then shift it into gear, it would definitely fail.

I'm not sure there is a real need to go over this distinction here though, you already know burnouts are hard on the car, you expect to break stuff by driving hard, and you will not stop. I don't think that you can expect any guarantees from anyone on a 20-year-old car that you openly state you will treat this way.

I can't resist asking: Why is a 6,000RPM burnout so important to you? Is a 5,000RPM burnout not adequate for some reason? Or even a 4,000RPM burnout?

6k burnouts aren’t a necessity. And going forward i definitely won’t be reving it out like that. But you make it seem like driving my sporty car (I hesitate to call it fast or muscle) aggressively is something to be shamed. They knew what they were making, thus they gave it the 65e trying to beef it up.
im not driving this way in my truck because yeah, nobody does that. But nobody rips on their muscle cars? That’* the whole point is it not? Why else am I putting gas into this heavy lump of metal?
I’m not roasting the tires at every stoplight. I feel like the occasional burnout is not an uncommon thing.